Tank Battery PLC Programming for Oil and Gas Producers
Key Takeaway
Tank battery PLC programming controls levels, dumps, LACT enable, vapor recovery, and high-high shutdowns that protect oil inventory and environmental compliance. Producers need reliable level strategies, fail-safe outputs, and SCADA visibility — not ad-hoc timers that overflow a tank at 2 a.m.
Quick Answer
A tank battery PLC runs the facility brain: inlet separators, oil and water tanks, gunbarrel or heater-treater interfaces, LACT enable, and vapor/flare permissives. Good programming turns noisy level transmitters into stable control and hard high-high trips that still work when cellular fails.
Core loops every battery needs
- Level measurement strategy: Radar, guided wave, or float — with filtering that does not hide a real high-high.
- Dump and transfer logic: Oil to sales, water to injection or SWD, with valve feedback and timeout faults.
- LACT handshake: Battery ready, BS&W/temperature permissives, and meter proving windows.
- VRU / flare / combustor permissives: Do not dump hydrocarbon vapor into an offline or faulted vapor system.
- Leak and spill detection hooks: Secondary containment switches and pad sump pumps where required.
Related reading: heater treater and separator automation and oilfield automation overview.
Fail-safe design that survives radio loss
If the SCADA path dies, tanks still fill. Local HH trips must open or close the correct valves without a host write. Document the de-energize-to-trip vs energize-to-trip choice for every critical solenoid. Pumpers should see “last good level” quality bits so they do not chase frozen values after a transmitter fault.
Commissioning checklist (controls + I&E)
- Simulate or water-test each HH/LL with the actual trip path.
- Verify valve fail positions match P&ID notes.
- Confirm analog scaling in PLC and SCADA match engineering units.
- Prove LACT enable only when battery conditions are true.
- Walk the pad with I&E to confirm junction box labels match the IO list.
NFM pairs oil and gas PLC programming with I&E field services so battery startups are not split across two vendors who never share a drawing set.
Need help with oil & gas field automation?
Texas-based licensed engineers — get a free, no-obligation assessment.
Frequently Asked Questions
CompactLogix and similar mid-range PLCs are common when the battery shares a pad controller with wells. Dedicated facility PLCs or RTUs appear on larger central batteries. The platform matters less than clear interlocks, owned source code, and SCADA tag discipline.
Many operators use a hardwired HH or safety relay in series with PLC permissive logic. At minimum, the trip must not depend on SCADA. Follow your corporate SIF/cause-and-effect standard and document both the device and the PLC path.
Frozen level values, inverted fail positions, and missing vapor-system permissives are classic causes of overflows and venting events. Commissioning that only checks ‘SCADA shows a number’ is not enough.
Still have questions about your setup? Talk to an engineer or call (210) 405-4248.