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Varec 8200 COT

Drop-In Current Output Transmitter

Varec 8200 COT

The Varec® 8200 Current Output Transmitter (COT) is designed for terminal instrumentation engineers, control systems integrators, and maintenance supervisors managing aging 8200 Current Output Transmitters on 2500 and 2520 float-and-tape gauges at petroleum terminals, fuel facilities, and industrial tank farms.

Unlike a full gauge replacement that adds new tank penetrations, fresh conduit runs, and an extended tank outage, the 8200 Electronics Upgrade is a drop-in retrofit: an 8920-class capacitive absolute encoder and electronics package that fits inside the existing 8200 COT cast aluminum enclosure and reuses the current mounting, conduit, and junction boxes.

The upgraded instrument delivers ±1/16 in (1.58 mm) level accuracy, a capacitive-touch LCD for local configuration and diagnostics, and a standard 4–20 mA output for PLC and DCS integration. Level ranges reach up to 120 ft (36 m). An optional second 4–20 mA loop adds temperature via 3-wire RTD, optional 2 or 4 SPDT limit switches add alarm and relay outputs, and HART output is planned for a future firmware release.

Loop-powered DC (20–48 VDC) and active AC (85–305 VAC) variants cover two-wire and AC-powered sites, with the upgraded instrument feeding FuelsManager® and SCADA via RTU analog input.

Varec 8200 COT
Varec 8200 COT
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Features

Drop-In Retrofit Design

Fits inside the existing 8200 COT cast aluminum enclosure and reuses mounting hardware, conduit, and junction boxes, so tank, gauge, and wiring stay put.

8920-Class Absolute Encoding

Capacitive absolute encoder with direct-drive gearing delivers ±1/16 in (1.58 mm) accuracy across ranges up to 120 ft (36 m) on one central shaft.

Tank-Side LCD Display

Capacitive-touch LCD provides local level indication, output scaling, parameter setup, and diagnostic status, adding visibility to instruments that previously had no local readout.

Flexible Power Options

Loop-powered DC (20–48 VDC) or active AC (85–305 VAC) variants cover two-wire loop sites and AC-powered instrument locations without redesigning the cabinet.

Standard 4–20 mA Integration

Primary 4–20 mA level output delivers PLC- and DCS-ready signals, with an optional second loop for 3-wire RTD temperature and HART in future firmware.

Integrated Alarm Switching

Optional 2 or 4 SPDT cam-operated limit switches add high-level alarms and relay outputs without a separate alarm transmitter in the loop.

Applications

  • Legacy COT Modernization: Aging 8200 COTs on 2500 and 2520 float-and-tape gauges are upgraded in place — no new tank penetrations, no conduit runs, no extended outage.
  • PLC and DCS Migration Projects: Control-system migrations that require 4–20 mA analog input receive consistent level signals from upgraded 8200s across mixed legacy fleets at a single site.
  • Tank-Side Visibility and Diagnostics: Adds local LCD indication, configuration, and diagnostics to instruments that previously offered no tank-side readout, supporting faster routine checks.
  • Combined Level and Temperature: The optional second 4–20 mA loop adds temperature alongside level on one instrument, reducing the need for a separate temperature transmitter in the loop.
  • Audit and Documentation Practice: Refreshes legacy 8200 installations with auditable measurement records and tank-side diagnostics, supporting documentation practice aligned with EPA SPCC programs.
  • Asset-Life Extension Programs: Reuses mechanically sound 2500/2520 gauges and housings, extending the life of the installed gauging while bringing the electronics into current control-room standards.
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Specifications

Parameter

Specification

Accuracy

±1/16 in (1.58 mm) level

Repeatability

≈0.16% of full range

Level Range

Up to 120 ft (36 m)

Primary Output

4–20 mA (level)

Optional Output

4–20 mA (temperature via 3-wire RTD); HART (pending future firmware)

Power — DC variant

20–48 VDC (loop-powered)

Power — AC variant

85–305 VAC (active power variant)

Enclosure

Existing 8200 cast aluminum housing retained

Display

Capacitive-touch LCD for local configuration and diagnostics

Alarm Options

2 or 4 SPDT cam-operated limit switches

Configurations

External and junction-box configurations

Host Integration

FuelsManager® and SCADA via RTU analog input

Host Gauge Compatibility

Varec 2500 / 2520 float-and-tape gauges with existing 8200 COT

Contact Support
2026 COST ESTIMATE

Contact Support

If you have questions not covered here, please contact the Cognesense support team for assistance.

What does the 8200 Electronics Upgrade actually change?

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It replaces the encoder and electronics inside the existing 8200 COT housing with an 8920-class capacitive absolute encoder, a capacitive-touch LCD, and current 4–20 mA output. The housing, conduit, junction boxes, and mechanical gauging stay in place.

Will the existing approvals be maintained after the upgrade?

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The retrofit retains the original housing and existing conduit and junction connections. Whether the upgraded assembly continues to carry the original jurisdiction approvals depends on the approval basis, the local regulatory authority, and any changes in hazardous area classification since the original installation. Confirm with the site compliance team before returning the instrument to service.

Do I need to pull new cable?

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Typically, no. The DC variant remains a two-wire 4–20 mA loop using the existing cable. Verify allowable loop resistance with MAX RESISTANCE = 50 × (V_supply − 15) and confirm the receiver load. Field wire must be 22 AWG or heavier.

Can I add temperature measurement later?

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The optional second 4–20 mA temperature output requires the dual-loop variant, which must be specified at time of ordering. The RTD input terminals are not field-retrofittable on single-loop units.

What if my site uses limit switches for high-level alarms?

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Select the 2 or 4 SPDT cam-operated limit switch option when ordering. Switches are positioned at the required set points during installation and setup — no separate alarm transmitter is needed in the loop.

Is the 8200 Electronics Upgrade suitable if the mechanical gauge is also deteriorating?

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No. The upgrade assumes a mechanically sound host gauge. If the float, tape, sprocket, or housing has deteriorated to the point where accuracy or reliability is compromised by the mechanical components, a full gauge replacement is the correct path.

What level range does the upgrade support?

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Up to 120 ft (36 m), with ±1/16 in (1.58 mm) accuracy and repeatability on the order of 0.16% of full range — sufficient for inventory and operational use, and aligned with what the Varec 2920 FTT and 8920 LPT deliver.

How does the upgraded 8200 reach FuelsManager® and SCADA?

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The 4–20 mA level output (and optional temperature loop) feeds FuelsManager® and SCADA via an RTU analog input — typically the Varec 8810 RTU or 9810 miniRTU at the tank farm. HART digital output is planned for a future firmware release.

Summary

With over a century of tank gauging heritage, Cognesense brings the Varec 8200 Electronics Upgrade to operators extending the life of installed 2500 and 2520 float-and-tape gauges. An 8920-class capacitive absolute encoder drops into the existing 8200 COT housing to deliver ±1/16 in accuracy, a tank-side capacitive-touch LCD, and standard 4–20 mA output for PLC, DCS, and FuelsManager® integration — all without new tank penetrations or conduit. It is a legacy-preserving path to current control and measurement standards, trusted wherever you need to measure, monitor, and protect what matters most.

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