ABB

1.Main Functions

Multi‑range analog signal acquisition and conditioning: Receives low‑level analog signals from field sensors and transmitters. It performs amplification, impedance transformation, low‑pass filtering and signal scaling, and converts field analog inputs into standardized internal signals compatible with INFI‑90 back‑plane bus. PS851 supports expanded input signal ranges compared with PS830‑PS832A series.More products: www.plcva.com
Full galvanic isolation: Provides electrical isolation between field instrument circuits and DCS internal circuitry. It eliminates ground‑loop currents, common‑mode noise and transient surge interference caused by long field wiring, protecting downstream DCS I/O and controller hardware.

PS 851 Isolated Analog Input Signal Conditioning Module

Hardware zero‑point and span calibration: Equipped with adjustable potentiometers for on‑site offset and gain calibration. Maintenance engineers can tune zero offset and full‑scale span parameters to compensate for sensor drift and match different transducer output characteristics.
Signal‑level interface conversion: Acts as an electrical interface bridge between field‑side process instrumentation and INFI‑90 rack back‑plane bus. It adapts diverse non‑standard field sensor outputs for subsequent DCS processing modules.

PS 851 Isolated Analog Input Signal Conditioning Module

Heavy‑duty noise filtering: Implements multi‑stage analog filtering circuits to suppress high‑frequency EMI noise and signal jitter. It delivers stable analog measurement values for process control loops.plcva.com
Channel‑level signal integrity protection: Improves signal fidelity in high‑electromagnetic‑interference environments, reducing measurement distortion and enhancing overall system measurement reliability.

PS 851 Isolated Analog Input Signal Conditioning Module

Legacy INFI‑90 DCS cabinet deployment: Installed inside standard ABB Bailey INFI‑90 racks, located between field instrument wiring and DCS main processing I/O boards.
Industrial process analog measurement: Collects and conditions analog signals from pressure transmitters, flow transmitters, level sensors and analog temperature transducers in process industries.

PS 851 Isolated Analog Input Signal Conditioning Module

High‑interference heavy‑industry sites: Applied widely in thermal power plants, chemical processing plants, pulp‑and‑paper mills and metallurgical plants with long field cables and severe electromagnetic disturbances.
Plant maintenance, spare‑part replacement and retrofitting: Serves as critical spare replacement component for aging INFI‑90 control racks, used for equipment overhaul, on‑site repair and legacy‑system modernization projects.
Process closed‑loop regulation: Supplies conditioned stable process variable signals to DCS PID control algorithms, supporting reliable automatic closed‑loop control for key production loops.