SCADA Fundamentals Glossary
Supervisory control, telemetry, polling, and the core building blocks of a SCADA system. 253 terms in this topic - each defined in plain English on its own page.
SCADA is the layer that watches and commands a distributed process: field devices report measurements to a central system, operators see live values and alarms, and commands travel back down to the equipment. The terms in this topic cover that supervisory layer itself - how data is collected (polling, report by exception, store and forward), the roles in the architecture (master station, outstation, data concentrator), and the operating concepts a control room runs on. If you are new to the field, read the beginner's guide first, then use these definitions as a reference while you work.
253 Terms
What is the 3-2-1 backup rule for SCADA?
Three copies, two media, one offsite - and why the air-gapped copy is what defeats SCADA ransomware.
Read → GlossaryWhat is an adaptive poll rate in SCADA?
A poll rate that speeds up for sites in alarm or changing and slows down when quiet, cutting cellular data cost.
Read → GlossaryWhat is API pagination for SCADA bulk data pulls?
Pulling large tag-history ranges through a paged REST API without dropping rows, using cursors, resume, and backoff.
Read → GlossaryWhat Does Five Nines Availability Mean for SCADA?
How 99.9, 99.99, and 99.999 percent uptime translate to yearly downtime and the architecture each needs.
Read → GlossaryWhat Is a Bad-Quality Tag in SCADA and What Makes a Tag Go Bad?
What the Bad flag on an HMI means, the causes that force it, and how to clear it by fixing the source.
Read → GlossaryWhat Is Bandwidth?
Telemetry data rate, how it differs from latency, and how remote sites conserve it - explained.
Read → GlossaryWhat is a bare-metal restore for a SCADA server?
Rebuilding a whole SCADA server - OS, drivers, apps, config - onto blank hardware from a full image.
Read → GlossaryWhat is battery temperature derating at a remote site?
Cold cuts capacity, heat cuts life: the derate factors, temperature-compensated charging, and the lithium cold-charge limit.
Read → GlossaryBuffer MQTT Telemetry Through a Cellular Outage
Combine edge store-and-forward, a long session expiry, and QoS 1 so an outage leaves no gap and no recovery flood.
Read → GlossaryHow do you bulk-provision SCADA tags from a spreadsheet?
Import hundreds of tags from a CSV with column mapping, duplicate validation, a dry-run preview, and rollback.
Read → GlossaryWhat Is a Canonical Tag Name in SCADA?
The single authoritative golden identifier a cloud SCADA assigns above many device-native tag names.
Read → GlossaryChoose an MQTT QoS for Telemetry
Pick QoS 0, 1, or 2 per topic by matching the delivery guarantee to what breaks on loss or duplication.
Read → GlossaryHow do you choose MQTT QoS?
Match QoS to message type: 0 for frequent readings, 1 for events and commands you must not lose, and 2 only where duplicates are unacceptable.
Read → GlossaryReport by exception or polling: which to use?
Match the update model to the link and data cost, solve liveness separately, and blend the two per point-group.
Read → GlossaryWhat Is Cloud Autoscaling?
The cloud automatically adding and removing compute as load changes, so you pay only for what you use.
Read → GlossaryWhat is cold storage SCADA?
Whole-facility supervision of a refrigerated warehouse: zones, refrigeration plant, sequencing and excursion alarms.
Read → GlossaryWhat is a collector store-and-forward buffer?
Local disk or memory cache that spools historian data during an archive outage; size it right or lose the oldest data.
Read → GlossaryWhat Are Communication Retries and Timeouts?
How a master decides a poll failed, how many retries before offline, and how it affects data quality.
Read → GlossaryWhat is the difference between a comm timeout and a no response in SCADA?
No response means total silence; a timeout can also fire on late, partial, or CRC-failed replies. Each points to a different fix.
Read → GlossaryHow do you commission a store-and-forward repeater?
Verify both hops independently, set the relay mode, prove end-to-end polling, and force an outage to confirm buffered data forwards on recovery.
Read → GlossaryHow do you commission gas-lift telemetry?
Verify the casing and tubing transmitters, scale each channel, set operating-range alarms, and confirm the trends.
Read → GlossaryWhat Is a Comms-Fail Alarm?
The SCADA alert raised when a site stops responding, flagging that its data is stale and the process is unseen.
Read → GlossaryWhat is concurrent vs named-user licensing?
Session-pool counting versus per-seat assignment, and which fits shift-based control rooms vs occasional web viewers.
Read → GlossaryWhat is a configuration change audit trail in SCADA?
An immutable log of every setpoint, alarm-limit, and permission change with who, when, and old-vs-new value.
Read → GlossaryHow do you configure a comms-fail alarm?
Detect silence with a watchdog or heartbeat, set the timeout from the link, and mark the dead device's data bad, not just alarm.
Read → GlossaryHow do you configure a quality-flag strategy?
Define good, bad, and uncertain states, propagate them through calcs and history, and make alarms and displays respect quality.
Read → GlossaryHow do you configure store-and-forward buffering?
Size the buffer for the worst outage, keep source timestamps, and forward on reconnect without gaps or duplicates.
Read → GlossaryHow do you configure store-and-forward on a gateway?
Enable buffering with original timestamps, size the buffer to the worst outage, set overflow behavior, and test for no loss.
Read → GlossaryWhat Is Containerization?
Packaging an app with its dependencies into a lightweight portable unit that runs identically anywhere.
Read → GlossaryWhat Is a Control Narrative?
The plain-language document that defines how a process is controlled, what it contains, and how it drives PLC programming and testing.
Read → GlossaryWhat Is a Control Room Console?
The operator workstation of screens, controls, and comms that runs a facility.
Read → GlossaryWhat is the PHMSA control room management rule?
The eight-element program under 49 CFR 192.631 and 195.446, and how SCADA and alarm practices support each one.
Read → GlossaryWhat is a control scheme in process control?
The arrangement of loops, feedback, cascade, override, and split-range, that meets a process objective.
Read → GlossaryWhat Is a Rollback Plan for a SCADA Cutover?
The pre-agreed procedure to safely revert to the legacy SCADA if a cutover fails, with triggers and testing.
Read → GlossaryWhat is dam safety instrumentation SCADA?
The level, seepage, uplift, and movement sensors trended against thresholds so SCADA gives early warning of dam problems.
Read → GlossaryWhat Is a Data Concentrator?
The field device that aggregates many downstream RTUs and meters onto one upstream link to the host.
Read → GlossaryWhat Is a SCADA Data Dictionary?
The documented catalog of every tag's meaning - units, ranges, source, update rate - so anyone can interpret the data.
Read → GlossaryWhat Is Data Enrichment in SCADA?
Adding context like asset ID, location, and units to raw telemetry so dashboards and analytics are self-describing.
Read → GlossaryWhat Does a Data Steward Do in SCADA Governance?
The named person who owns tag definitions, approves naming and scaling changes, and answers for data quality.
Read → GlossaryWhat Is Days of Autonomy in a Solar SCADA Site?
How many sunless days a site runs on battery before hitting its depth-of-discharge floor - usually 5 to 7.
Read → GlossaryWhat Is a Dead Tag in SCADA?
A configured tag that never received data or stopped forever - distinct from a frozen or merely stale point.
Read → GlossaryWhat Is Delta-Time (dt) in SCADA Calculations?
Why rate and integral math must use the real elapsed time, how to capture dt, and the drift from assuming a fixed scan.
Read → GlossaryHow do you design a SCADA tag naming convention?
Pick the fields, order them site to measurement, fix a delimiter and length budget, and publish the standard before you build.
Read → GlossaryWhy are my Modbus polling cycles slow?
Measure the cycle, break it down per device, find time lost to scattered reads and retries, then fix the biggest contributor.
Read → GlossaryWhat Are Digital vs Analog SCADA Points?
The status, measured, counter, and control point types that classify tags in a SCADA database.
Read → GlossaryWhat is DirectQuery vs import mode for SCADA dashboards?
Live queries against the source versus cached data in the model, and why huge time-series volumes force DirectQuery or pre-aggregation.
Read → GlossaryWhat is district heating SCADA?
Supervising a heat network: substation telemetry, supply and return temperatures, and weather-compensated control.
Read → GlossaryWhat Is a DNP3 Class 0 Poll?
The full static-value snapshot a DNP3 master reads to re-baseline current state, versus incremental Class 1/2/3 event polls.
Read → GlossaryWhat Are DNP3 Master and Outstation Addresses?
The link-layer source and destination addresses that identify DNP3 devices, how they differ from IP, and why a mismatch silently drops the poll.
Read → GlossaryHow do you plan DNP3 poll rates?
Event polls or unsolicited for routine data, integrity polls on connect, recovery, and restart triggers, plus a scheduled backstop.
Read → GlossaryDNP3 Unsolicited Response
How an outstation pushes events to the master without being polled.
Read → GlossaryWhat is a dual-NIC SCADA server?
A multihomed server with one NIC on the control network and one on the business side - and how to keep them apart.
Read → GlossaryWhat Is Dual-Path Telemetry Redundancy?
Running two independent comm paths with automatic failover so one outage cannot silence a critical site.
Read → GlossaryEdge processing or central polling?
A selection guide on where computation belongs, comparing bandwidth, latency, and field complexity, with a split rule.
Read → GlossaryHow do you enable DNP3 unsolicited reporting?
Enable per class at the outstation, permit and re-enable at the master, prove the restart handshake, and keep a backup poll.
Read → GlossaryWhat Is an Engineering Unit Mismatch in SCADA?
When a tag's value and its declared unit disagree, or two systems assume different units, corrupting math and reports.
Read → GlossaryWhat Is ERP Integration in SCADA?
The two-way link that posts production data up to SAP or Oracle and brings work orders back down.
Read → GlossaryWhat Is eSIM and Remote SIM Provisioning for SCADA?
An embedded eUICC that switches carrier profiles over the air without a truck roll, with multi-IMSI roaming.
Read → GlossaryWhat Is an Event Log?
The timestamped record of alarms, operator actions, and system events.
Read → GlossaryWhat Is Fade Margin?
The dB cushion above receiver sensitivity that keeps a link up through weather and multipath.
Read → GlossaryWhat is firmware load shedding at a remote site?
A controller dropping heaters, cameras, and reporting rate in priority order as the battery sags, to keep core telemetry alive.
Read → GlossaryWhat Is First Energization During Commissioning?
The controlled first application of power to panels and control hardware, a high-risk milestone with strict procedures.
Read → GlossaryFix Duplicate Telemetry in an OPC UA to MQTT Bridge
Trace duplicates to reconnect republish, QoS 1 redelivery, or double-monitoring, and de-duplicate on a stable key.
Read → GlossaryWhat Is a Fixed-IP SIM Card?
A cellular SIM provisioned with a persistent, addressable IP so a remote field device stays directly reachable.
Read → GlossaryWhat Is a Forced Tag in SCADA?
When an engineer overrides a live value so the system reads a forced number, and the risk of forgotten forces.
Read → GlossaryWhat Is a Front-End Processor?
The dedicated comms server that offloads polling and protocol handling from the SCADA master station.
Read → GlossaryWhat Is a Future-Dated Timestamp in SCADA?
How a wrong clock, doubled timezone offset, or GPS rollover pushes data into the future and freezes trends and last-value queries.
Read → GlossaryWhat is a geofence entry or exit event in SCADA?
An event fired when a GPS position crosses a virtual boundary, for crew arrival, theft detection, and site polling.
Read → GlossaryWhat Is Geographic Redundancy in SCADA?
Redundancy across physically separate sites so a fire, flood, or power loss at one location does not end supervision.
Read → GlossaryWhat Is a Geospatial Map Display in SCADA?
A map that plots assets at real coordinates with live status for at-a-glance fleet awareness.
Read → GlossaryWhat Is a Golden Image?
A hardened, standardized OS and app template cloned to deploy identical HMI stations, edge devices, or VMs.
Read → GlossaryWhat Is a Golden Record for a SCADA Tag?
The one reconciled, trusted version of a tag's metadata, built from conflicting sources by survivorship rules.
Read → GlossaryWhat Is a HART Polling Address?
The short address where 0 means live analog and a nonzero value parks the current for digital-only multidrop operation.
Read → GlossaryHeartbeat Signal
A periodic keepalive that proves a device or link is alive, letting SCADA detect silent failures and stale data.
Read → GlossaryWhat Is a Heat Map Display in SCADA?
A colour-coded grid of similar assets that surfaces outliers across a large fleet at a glance.
Read → GlossaryWhat Is a Hot Standby SCADA Server?
A fully-running backup server that mirrors live state so it takes over in seconds with no data gap.
Read → GlossaryHow do I add a tag to SCADA?
Pick the device and register, set type, scaling, units, and name, then verify the live value before saving.
Read → GlossaryHow do I build a trend in SCADA?
Add pens, assign colors and axes, set the window and refresh, pick real-time or historical, and decimate long ranges.
Read → GlossaryHow do I build an HMI screen in SCADA?
Lay out a process mimic, add and bind display objects, add navigation, and use calm high-performance HMI color.
Read → GlossaryHow do I configure an alarm in SCADA?
Assign the tag, set HI and LO limits and priorities, add deadband and delay, write a clear message, then test it.
Read → GlossaryHow do I configure an email alarm notification in SCADA?
Enter SMTP settings, build a rule by priority, add recipients and a clear message template, then test delivery.
Read → GlossaryHow do I create a user role in SCADA?
Name the role, pick granular permissions, scope it to areas, assign users, and grant only least privilege.
Read → GlossaryHow do I import tags from a CSV in SCADA?
Build the columns from a template, avoid name collisions, validate before commit, and keep a backup to roll back.
Read → GlossaryHow do I schedule a backup in SCADA?
Choose what to capture, set frequency and retention, store a copy offsite and immutable, and test the restore.
Read → GlossaryHow do I set scan rates in SCADA?
Group tags into fast and slow scan classes, balance responsiveness against PLC load and data cost, and use deadband.
Read → GlossaryHow do I set up SMS alerts in SCADA?
Connect a gateway or provider, trigger texts by high priority, add on-call numbers, and add throttling and quiet hours.
Read → GlossaryWhat is an HTML5 thin client for SCADA?
A zero-install client that renders SCADA screens in a browser over HTTPS, with nothing local to patch.
Read → GlossaryWhat Is a Hybrid SCADA Architecture?
Time-critical control and local HMI stay at the edge while historian and multi-site views live in the cloud.
Read → GlossaryWhat Is a Hypervisor?
The software layer that runs many isolated SCADA/HMI VMs on one server, plus Type 1 vs Type 2 in OT.
Read → GlossaryHow do you inspect a battery bank?
Look before touching: cases, corrosion, torque, electrolyte, per-unit voltages, all recorded against the last visit.
Read → GlossaryHow do you inspect a solar array?
Shading survey at panel level, glass and connector checks, mounting torque, and a before-and-after current reading.
Read → GlossaryIntegrity Poll
The periodic full read a DNP3 master performs to re-synchronize with an RTU and recover after event buffer overflow or a restart.
Read → GlossaryWhat Is a Jitter Buffer?
The receive-side buffer that absorbs variable arrival timing so downstream logic sees an even, ordered stream.
Read → GlossaryWhat is a JSON payload schema for SCADA telemetry?
Designing the value, quality, timestamp, and units envelope that carries a SCADA reading to the cloud.
Read → GlossaryKeepalive
A small periodic message that keeps an idle SCADA connection open and detected as live through firewalls, NAT, and cellular timeouts.
Read → GlossaryWhat is kiosk mode for a SCADA HMI?
Runs a dashboard locked full-screen on an unattended display, read-only, no navigation away, with auto-recovery on reboot.
Read → GlossaryWhat Is a Leap Second and How Does It Affect SCADA Timestamps?
How an inserted second can duplicate or reverse timestamps and break event ordering, plus leap smearing.
Read → GlossaryWhat Is the Difference Between LEO and GEO Satellite Telemetry?
How low-earth-orbit constellations beat geostationary VSAT on latency and antenna size, and how orbit shapes SCADA design.
Read → GlossaryWhat is a license audit and true-up?
Reconciling deployed tags and seats against entitlements, the true-up bill, and how to track usage to avoid it.
Read → GlossaryWhat Is Licensed Radio Telemetry?
FCC-licensed narrowband SCADA radios, licensed vs unlicensed, and why oilfields still run private networks - explained.
Read → GlossaryWhat is better for solar SCADA, LiFePO4 or lead-acid?
Compare usable capacity, cycle life, and cost, with the freezing-temperature charge caveat that trips up northern installs.
Read → GlossaryWhat Is Listen-Before-Talk in Radio Telemetry?
How radios sense a shared channel and wait before transmitting to avoid collisions, and its effect on throughput.
Read → GlossaryLocal hand-off-auto or SCADA remote motor control?
A selection guide comparing safety, maintenance access, and automation for local HOA versus SCADA control - and why most schemes keep both.
Read → GlossaryWhat Is Master / Outstation Architecture?
The request/response roles - master initiates, outstations answer - that frame all SCADA polling.
Read → GlossaryWhat Is a Master Terminal Unit (MTU)?
The SCADA master station that polls RTUs, hosts the central database, and drives operator displays.
Read → GlossaryWhat Is a Mimic Diagram?
The schematic process graphic that mirrors plant equipment on an operator screen.
Read → GlossaryMQTT 3.1.1 or MQTT 5 for SCADA?
A side-by-side of what MQTT 5 adds, reason codes, session expiry, flow control, properties, and when each version still wins.
Read → GlossaryMQTT or AMQP for industrial telemetry?
A selection guide comparing lightweight device push against richer message queuing, with a rule that follows the layer.
Read → GlossaryMQTT or polling for a large fleet?
A selection guide comparing fan-out, bandwidth, and liveness as device count climbs, with a clear rule for when to publish.
Read → GlossaryWhat Is a Multi-Cloud Deployment?
Running workloads across two or more cloud providers for resilience, portability, and data residency.
Read → GlossaryWhat Is a Poll Collision on a Multidrop RS-485 Bus and Why Do Devices Intermittently Drop?
How duplicate addresses or overlapping replies garble each other into random CRC errors, and how to spot contention versus a dead device.
Read → GlossaryWhat Is a Tag Naming Collision in SCADA?
When two distinct points end up with the same name and one overwrites or shadows the other, corrupting data.
Read → GlossaryWhat Are NaN and Infinity Values in SCADA Tags?
How IEEE-754 special values arise in calculated tags, poison downstream aggregates, and must be trapped and flagged.
Read → GlossaryWhat Is NAT Traversal for Remote SCADA Gateways?
Why a gateway behind carrier-grade NAT can't accept inbound polls, and the outbound-initiated patterns that solve it.
Read → GlossaryWhat Is NB-IoT for SCADA Telemetry?
The low-power, deep-coverage cellular class for small periodic payloads, its trade-offs, and how it compares to Cat-M and LTE.
Read → GlossaryWhat Is NTP Time Synchronization?
Keeping every RTU clock aligned so event ordering, sequence-of-events analysis, and buffered timestamps stay trustworthy.
Read → GlossaryWhat Is a DNP3 Null Unsolicited Response?
The data-free DNP3 message that carries only status flags to prove a link is alive and signal outstation restarts.
Read → GlossaryWhat is OAuth 2 client credentials for SCADA API integration?
Machine-to-machine auth for SCADA-to-cloud REST calls using short-lived scoped bearer tokens instead of static keys.
Read → GlossaryOn-premise or cloud SCADA hosting?
Keep closed-loop control in field devices, then decide where supervision and history live: local for isolated sites, cloud for connected fleets, hybrid for most.
Read → GlossaryWhat Is Operator Effectiveness?
How well an operator detects, diagnoses, and responds - and what drives it.
Read → GlossaryWhat Are Operator Rounds?
Scheduled walkdowns where operators inspect equipment SCADA cannot see.
Read → GlossaryWhat is operator span of control in remote monitoring?
How many assets one operator can effectively watch, and how exception-based SCADA expands the ratio.
Read → GlossaryHow do you organize tags into UDT templates?
Model one asset type as a definition, instance it per device with minimal parameters, and change every copy from one edit.
Read → GlossaryWhat is an out-of-service tag in SCADA?
A whole-tag maintenance state that inhibits alarms, excludes bad data from reports, and shows a clear indicator.
Read → GlossaryWhat Is a Parallel Run During a SCADA Migration?
Running the new SCADA alongside the legacy system on the same live data to compare before retiring the old.
Read → GlossaryWhat is a Parquet file partitioning strategy for SCADA data lakes?
Laying out SCADA telemetry as Parquet by date and site, with compaction and column pruning for fast, cheap queries.
Read → GlossaryWhat are peak sun hours in solar SCADA sizing?
The equivalent full-sun hours a site gets per day, not daylight hours; the worst-month value drives panel and battery sizing.
Read → GlossaryWhat Is Pipeline SCADA?
The control-center system that runs a pipeline from one screen.
Read → GlossaryHow do you plan a SCADA tag migration?
Build a complete old-to-new mapping, decide how history follows each tag, and cut over in stages with the old system as rollback.
Read → GlossaryWhat Is Clock Drift Between a PLC and SCADA and Why Do Timestamps Disagree?
How unsynchronized field clocks slowly diverge from server time, corrupting event ordering and history.
Read → GlossaryWhat Is a Point-to-Point Checkout in SCADA Commissioning?
Verifying every field wire lands on the correct terminal and I/O channel before loops are energized.
Read → GlossaryPoll Group
A batch of device points SCADA reads in one request instead of individually, cutting round trips and speeding up polling on slow links.
Read → GlossaryWhat is a poll priority scheme in SCADA?
Tag priority tiers that poll safety-critical data every cycle and trend-only tags less often, bounding worst-case latency.
Read → GlossaryWhat Is Poll Scheduling (Round-Robin)?
How a master orders and paces polls across many devices on one shared link, with round-robin and priorities.
Read → GlossaryPolled or event-driven telemetry cost?
Polling costs tag count times poll rate regardless of activity; event-driven costs scale with real changes, so slow-moving data on a metered link is far cheaper reported by exception.
Read → GlossaryWhat is a Power BI DirectQuery SCADA connection?
Querying the SCADA historian live in Power BI, relying on query folding and aggregation pushdown to avoid table scans.
Read → GlossaryWhat is a Power BI on-premises data gateway for SCADA data?
The service that lets cloud Power BI query an on-prem historian through outbound connections, without opening inbound ports.
Read → GlossaryWhat is a Power BI push dataset for real-time SCADA?
Streaming live SCADA values onto dashboards via a REST rows endpoint, with retention limits and row-rate throttling.
Read → GlossaryWhat Is Private LTE for SCADA?
A self-operated cellular network over CBRS or licensed spectrum covering a site public carriers cannot reach.
Read → GlossaryWhat Is Protocol Overhead?
The header and polling bytes that inflate telemetry traffic far beyond the raw readings you actually send.
Read → GlossaryHow do you provision and activate a SCADA SIM?
Record the identifiers, assign APN and plan, activate on the platform, and verify the first attach and host reach before leaving.
Read → GlossaryWhat Is PTP (IEEE 1588) Time Synchronization?
Sub-microsecond clock sync with grandmaster, boundary, and transparent clocks, and when PTP beats NTP.
Read → GlossaryWhat is quiescent current in a field device?
The always-on standby draw of controllers and converters whose summed microamps can dominate a small solar node's budget.
Read → GlossaryWhat is recirculating aquaculture system (RAS) SCADA?
Supervising a land-based fish farm's water quality, treatment loops and pumps with cascading alarms.
Read → GlossaryWhat Is a Rate of Change (ROC) Calculation in SCADA?
The derived per-minute rate that alarms on fast pressure or level moves before a fixed limit is hit.
Read → GlossaryWhat Is a Rate-of-Change Limit Check in SCADA?
A validation rule that flags readings changing faster than physically possible as suspect, even when in range.
Read → GlossaryWhat Is a Reasonability Range Check in SCADA Data?
Bounding an incoming value against a sensor's physical range and clamping or flagging bad readings.
Read → GlossaryWhat is reconnect backoff for telemetry clients?
Exponential backoff with jitter so hundreds of gateways do not hammer the broker at once after an outage.
Read → GlossaryWhat is redundant polling with a dual master in SCADA?
Two masters share device scanning with arbitrated ownership so a standby takes over on failure without double-polling.
Read → GlossaryWhat Is a Redundant Server Pair in SCADA?
The two-node building block: how a primary and backup are cabled, synced, and how the pair fails as a unit.
Read → GlossaryWhat is a remote access broker for SCADA?
An outbound-only agent meets a cloud relay so technicians reach OT assets with no inbound holes or VPN.
Read → GlossaryWhat Is a Remote Desktop Gateway?
A hardened broker that terminates encrypted RDP at the OT perimeter so HMIs are never directly exposed.
Read → GlossaryRemote Monitoring
Continuously watching distributed field assets from one location over telemetry - and how it differs from remote control.
Read → GlossarySolar, TEG, or fuel cell for remote site power?
A selection guide to off-grid SCADA power comparing load size, climate, fuel availability, and maintenance across three sources - plus when a hybrid wins.
Read → GlossaryWhat is a load profile and why does it matter for remote power?
Characterize base draw, intermittent spikes, and seasonal load so average sizes storage and peak sizes wire.
Read → GlossaryWhy does a DNP3 outstation keep restarting?
Log the restart flag, read the pattern: night-time clusters mean power, regular intervals mean watchdog, one operation means firmware.
Read → GlossaryWhat is report by exception in Sparkplug?
Publishing a metric only when it changes past a deadband, the practice that gives Sparkplug its bandwidth efficiency and reshapes how you read silence.
Read → GlossaryWhat Is Reporting Deadband vs Control Deadband?
The threshold that decides when to transmit a new value versus the deadband used inside a controller.
Read → GlossaryWhat is REST API polling vs webhook push in SCADA integration?
Client-asks-on-an-interval versus SCADA-calls-on-an-event: latency, waste, rate limits, and reachability compared.
Read → GlossaryWhat Is a Reverse Connection?
The phone-home broker pattern where the field device opens the link, so no inbound ports or public IPs are needed.
Read → GlossaryWhat is a reverse proxy in a SCADA DMZ?
An application-layer proxy that publishes a web HMI safely: TLS termination, auth pre-check, and hidden hosts.
Read → GlossaryRound-Trip Time (RTT)
The there-and-back delay of one poll, which usually limits how many devices a SCADA channel can serve on slow links.
Read → GlossaryWhat Is RTU Local Control vs Supervisory Control?
Why the wellhead RTU runs pump and shut-in logic itself and keeps controlling the well when the link drops.
Read → GlossaryWhat is a SCADA runtime meter to CMMS PM trigger?
Streaming live run hours and cycle counts into a CMMS meter so a threshold spawns usage-based PM work orders.
Read → GlossaryWhat is a SAP IDoc interface for SCADA production data?
Posting SCADA production totals into SAP as IDocs, with segment mapping, RFC and ALE plumbing, and status 51 handling.
Read → GlossaryWhat Is Satellite Telemetry?
How GEO and LEO satellite links carry SCADA data from sites with no cellular coverage - explained.
Read → GlossaryWhat Is a Cutover When Replacing a SCADA System?
The controlled switch from an old SCADA to a new one, big-bang or phased, without leaving the facility blind.
Read → GlossaryWhat is a DMZ for a SCADA system?
The buffered mid-zone between plant OT and enterprise IT, what shared services live in it, and why no IT host reaches a PLC.
Read → GlossaryWhat Goes Into a SCADA Disaster Recovery Plan?
The written DR document: recovery objectives, roles and call-tree, ordered restore steps, alternate site, and comms.
Read → GlossaryHow Does SCADA Failover Work?
The failover event end to end - detection, the switch decision, the handoff, and reconnecting operators and devices.
Read → GlossaryWhy Should You Run a SCADA Failover Drill?
Redundancy is unproven until tested; how to run a safe planned switchover and the surprises drills expose.
Read → GlossarySCADA Gateway
The device that connects field networks to higher-level SCADA or cloud systems, translating protocols, aggregating data, and enforcing the OT/IT boundary.
Read → GlossaryWhat is a SCADA license server?
The service that hands out floating licenses at runtime; why 24/7 SCADA deploys it redundantly.
Read → GlossaryWhat Is SCADA Middleware?
The software tier that translates, buffers, and decouples field data from enterprise and cloud systems.
Read → GlossaryHow Do You Plan a SCADA Migration?
The discipline of scoping, sequencing, and de-risking a move off legacy SCADA across a fleet of sites.
Read → GlossaryWhat is SCADA server sizing?
Right-sizing CPU and RAM from tag count, client sessions, scan rate and alarm load, with headroom to spare.
Read → GlossaryWhat Is a SCADA Tag?
The named data point that links a field value to displays, alarms, and history, naming conventions, and mapping to protocols.
Read → GlossaryWhat is SCADA to AWS IoT Core integration?
Bridging field MQTT into AWS IoT Core, with topic rules fanning data to Timestream, S3, and Kinesis and device certs securing gateways.
Read → GlossaryWhat is a SCADA to Google BigQuery pipeline?
Moving SCADA tags via Pub/Sub and the Storage Write API into time-partitioned, clustered BigQuery tables with dedup.
Read → GlossaryWhat is SCADA to Databricks lakehouse ingestion?
Landing SCADA telemetry in Delta Lake via Auto Loader or streaming, then refining raw tags through bronze, silver, and gold.
Read → GlossaryWhat is SCADA to ERP production posting?
Posting validated production and consumption volumes into an ERP as confirmations or goods movements, after VEE and allocation gates.
Read → GlossaryWhat is SCADA to Azure Event Hubs integration?
Streaming plant telemetry into Event Hubs as the Azure front door, with site partition keys, throughput units, and Capture.
Read → GlossaryWhat is SCADA to Kafka streaming integration?
Publishing SCADA tag changes onto Kafka topics, with keying for per-partition ordering and Connect sinks to warehouses.
Read → GlossaryWhat is SCADA to Power BI integration?
Connecting historian data into Power BI via a queryable source, with pre-aggregation and a star schema so dashboards stay fast.
Read → GlossaryWhat is SCADA to Snowflake integration?
Landing SCADA tags in Snowflake via Snowpipe or COPY INTO, with VARIANT payloads and time-clustered micro-partitions.
Read → GlossaryWhat is a SCADA virtualization host?
The physical box running the SCADA, historian, and engineering-station VMs - and why it needs clustering.
Read → GlossaryWhat Is a Scan Class?
How tags are grouped by update rate to balance responsiveness against bandwidth in PLC and SCADA polling.
Read → GlossaryWhat Is Scan Overrun in SCADA?
What happens when a poll or scan cycle cannot finish before the next is due, and how to diagnose it.
Read → GlossaryWhat is a schema registry for industrial telemetry?
A shared store of Avro or Protobuf contracts that enforces safe schema evolution across streaming telemetry.
Read → GlossaryWhat is SCIM user provisioning for SCADA?
Syncing SCADA accounts from a corporate directory so roles are assigned automatically and access ends on offboarding.
Read → GlossaryWhat is SD-WAN for connecting SCADA sites?
A redundant WAN overlay bonding cellular, broadband, and MPLS with sub-second failover to keep polling alive.
Read → GlossaryWhat Is Separation of Duties in SCADA?
Splitting a sensitive change across two people so no one can both make and approve it.
Read → GlossaryHow do you set alarm priorities in SCADA?
Rank each alarm by consequence and time to act, keep the levels few, and check the distribution forms a pyramid.
Read → GlossaryHow do you set up a SCADA audit trail?
Log config and operator actions with who, old-and-new value, and when, tied to real identities, tamper-evident, and retained.
Read → GlossaryHow do you set up a tank strapping table in SCADA?
Enter the certified level-to-volume points, configure interpolation, handle deadwood and roof corrections, and verify volume.
Read → GlossaryWhat is an SFTP file drop SCADA integration?
Scheduled flat-file exports to an SFTP landing zone, with atomic rename, filename conventions, and reconciliation.
Read → GlossaryOne site or geographic redundancy for SCADA?
Node redundancy survives a dead server, not a dead site; add a second location only when losing the primary site is a credible, intolerable event.
Read → GlossarySingle SCADA server or a redundant pair?
Decide by what breaks during the outage: a single box when control lives in the field, a redundant pair when the supervisory layer is on the critical path.
Read → GlossaryWhat does SCADA look like for a small water district?
Tank level, pump status, source flow, and chlorine, with alarms to an on-call operator, are the lean core.
Read → GlossaryHow do you select wire gauge for a solar SCADA array?
Size for both voltage drop and derated ampacity, take the larger gauge, and raise system voltage to shrink the wire.
Read → GlossaryHow do you size a solar panel for a remote SCADA site?
From daily Wh load and worst-month peak sun hours, through the derate stack, up to a standard panel with margin.
Read → GlossaryHow does SPCC drive tank monitoring?
How overfill prevention and containment requirements become level and containment telemetry that supports the plan in the field.
Read → GlossaryWhat Is a Split-Brain Condition in Redundant SCADA?
When a broken sync link makes both nodes act as primary and command the field - the risk and the defenses.
Read → GlossaryWhat is single sign-on for SCADA?
Logging into a cloud SCADA with a corporate identity via SAML or OIDC, centrally managed and instantly revoked.
Read → GlossaryHow do you set alarms to prevent a sewer overflow?
Place a high-level alarm with real lead time, add an independent high-high, and alarm the pump, mode, and communications failures directly.
Read → GlossaryHow do you stage a SCADA change with rollback?
Back up and verify first, write the exact rollback, apply in a window one step at a time, and check against a checklist.
Read → GlossaryWhat Is a Staging Environment for SCADA Testing?
A non-production copy where graphics, driver, and logic changes are validated with simulated data before going live.
Read → GlossaryWhat Is Static vs Dynamic IP?
How addresses are assigned, why cellular sites sit behind dynamic carrier NAT, and why outbound connections win.
Read → GlossaryHow does store-and-forward recovery ordering work?
How a reconnecting collector drains buffered history oldest-first alongside live data, with throttling to avoid overload.
Read → GlossaryWhat Is a Stuck-at-Zero Tag in SCADA?
When a tag pins at exactly zero from a broken wire or dead transmitter, and why zero looks deceptively plausible.
Read → GlossaryWhat Is a Synchrophasor and Phasor Data Concentrator (PDC)?
How a PMU makes GPS-timestamped phasors and a PDC time-aligns streams, with the C37.118 format and TVE limit.
Read → GlossaryWhat Is a SCADA Tag Census or Inventory Audit?
A periodic full count reconciling tags across PLC, historian, HMI, and licensing to reveal the true active inventory.
Read → GlossaryWhat Is a Tag Crosswalk or Mapping Table in SCADA?
The governed table that maps the same physical point across systems and naming schemes, keeping lineage intact.
Read → GlossaryWhat Is a Tag Detail Display?
The screen showing one tag's full value, limits, quality, and history.
Read → GlossaryWhat Is Tag Mapping When Migrating a SCADA System?
The crosswalk translating every legacy point to the new system, reconciling names, types, scaling, and alarms.
Read → GlossaryWhat Is a SCADA Tag Naming Convention?
Designing a consistent scheme of segments and delimiters so a historian stays searchable across sites.
Read → GlossaryWhat is a tag template in SCADA?
A reusable definition of an asset class's tags, scaling, and alarms so new sites are instanced, not hand-built.
Read → GlossaryWhat is a tag watchlist in SCADA?
An operator's ad-hoc live list of tags from across sites for troubleshooting, separate from the permanent dashboards.
Read → GlossaryWhat is a tag-based SCADA license?
Pricing that scales with I/O point count, sold in tiers, and how it shapes architecture and consolidation.
Read → GlossaryHow Does a Cellular Telemetry Data Plan Work?
How M2M pooled data plans, caps, and overage meet telemetry traffic, and how to budget monthly bytes.
Read → GlossaryWhat Is a Telemetry Data Radio?
The purpose-built radio modem that carries Modbus and DNP3 between RTUs and the SCADA host.
Read → GlossaryWhat Is a Telemetry Repeater Station?
The relay site on high ground that re-transmits field data to extend radio coverage over terrain.
Read → GlossaryWhat is a terminal server for SCADA?
A central session host running full SCADA clients as published apps or desktops, and its density and failure trade-offs.
Read → GlossaryWhat Is a Test Plan and Test Script for SCADA Acceptance Testing?
How acceptance testing is documented with expected results, pass/fail columns, traceability, and sign-off.
Read → GlossaryWhat Is a Thin Client?
A stateless terminal that renders a server-side HMI session, plus thin vs thick vs zero client for control rooms.
Read → GlossaryHistorian & Data / Data Integrity / Timestamp Source
Device-timestamped versus server-timestamped data, why it matters for buffering and events, and clock-sync pitfalls.
Read → GlossaryWhat is traffic shaping for telemetry links?
Prioritizing alarm and control traffic over bulk historian sync so critical packets are not queued behind backups.
Read → GlossaryWhat is tunnel ventilation control SCADA?
How road-tunnel SCADA holds air quality with CO/NO2 and opacity sensors driving jet fans, and switches to smoke control.
Read → GlossaryCan two DNP3 masters share one outstation?
Yes, with separate associations and buffers, distinct addresses, and a single owner for controls and time sync - never one shared queue.
Read → GlossaryTwo SCADA servers or three for quorum?
A pair cannot break a tie alone; add an odd third vote as a lightweight witness or a full server, and choose based on whether the third node also carries load.
Read → GlossaryWhat Is the Difference Between UDP and TCP for Telemetry?
Connectionless UDP versus connection-oriented TCP for SCADA, and their effect on bytes, battery, and loss.
Read → GlossaryUnsolicited Response
The DNP3 protocol mechanism - event buffers, classes, and confirmations - that lets an RTU push changes to the master without being polled.
Read → GlossaryHow do you validate a SCADA config before go-live?
Prove every point end to end, test alarms and calcs, exercise the failure paths, and sign off only what you actually verified.
Read → GlossaryHow do you verify a fixed-IP SIM reaches your host?
Confirm the address matches the record, prove the route both ways, and check the firewall rules that name the fixed address.
Read → GlossaryHow do you verify plunger cycle telemetry?
Confirm valve state, arrivals, and pressures reported remotely match the well and tell a coherent cycle story.
Read → GlossaryHow do you verify private-APN connectivity?
Confirm the APN name, check the address is in your private range, prove the route to your host, and prove the internet is blocked.
Read → GlossaryHow do you verify time sync across the stack?
Verify the reference clock first, check each layer against it, and prove event order with one injected event end to end.
Read → GlossaryWhat Is a Control Room Video Wall?
The shared large screen showing plant-wide status, trends, and alarms so the whole team shares one picture.
Read → GlossaryVirtualized or bare-metal SCADA host?
Virtualize by default for fast snapshot-and-restore recovery; stay bare-metal for tight-timing or hardware-bound systems, and never overcommit the host.
Read → GlossaryWhat is VM resource overcommit in a SCADA host?
Oversubscribing CPU and RAM saves money but can starve a real-time SCADA VM - why control VMs need reservations.
Read → GlossaryWhat Is the Difference Between Warm Standby and Cold Standby?
The two cheaper standby tiers below hot - warm (loaded, not synced) vs cold (off) - with real failover times.
Read → GlossaryWhat Is Water Treatment SCADA?
The monitoring layer tying plant, lift stations, tanks, and wells into one cloud-monitored system.
Read → GlossaryWhat Is a Webhook in SCADA Integration?
An outbound HTTP callback that pushes an event like an alarm to another service instead of being polled.
Read → GlossaryWhat is a webhook alarm push in SCADA?
Pushing a SCADA alarm event to an external HTTP endpoint the instant it fires, with a structured payload for ticketing and on-call.
Read → GlossaryWhat Is Poll Rate & Polling?
How SCADA requests data on a timer - choosing scan rates, poll-rate tuning, and polling vs report by exception.
Read → GlossaryWhat Is Publish/Subscribe (Pub/Sub)?
The event-driven messaging pattern behind MQTT and unified namespaces - decoupled producers and consumers, and pub/sub vs polling.
Read → GlossaryWhat Is Report by Exception (RBE)?
Sending data only when it changes past a deadband - how RBE and heartbeats work, RBE vs polling, and why it saves telemetry bandwidth.
Read → GlossaryWhat Is Store and Forward?
How RTUs and gateways buffer timestamped data through comms outages and backfill SCADA when the link returns, so no history is lost.
Read → GlossaryWhat Is Unsolicited Reporting?
How DNP3 RTUs push events to SCADA without being polled - unsolicited vs solicited responses and why it speeds up remote alarms.
Read → GlossaryHow to size a wind charger for a remote site?
Overlay the turbine's power curve on the site's real wind resource, check cut-in, and pair it with solar for winter.
Read → GlossaryWind Farm SCADA System
How a wind farm SCADA aggregates turbine, substation, and met-mast data into one control view.
Read → GlossaryWhat Is a Word Swap and Byte Swap for Float Values?
Why a 32-bit float across two registers can decode as garbage or NaN, and how to fix the order.
Read → GlossaryWhat Is an XY Plot in SCADA?
A chart of one variable against another, used for pump curves, compressor maps, and spotting drift.
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