HART-Transparent Driver (PR 9107A / PR 9107B)

Control signals to a hazardous area need the same intrinsically safe barrier as measurement signals coming out of it, with one extra requirement: the valve positioner or I/P converter at the far end has to keep its HART communication so it can be calibrated and diagnosed from the control room. The PR 9107 is the output driver for exactly this. It receives the 4–20 mA control signal from the DCS or PLC, isolates it galvanically and supplies an intrinsically safe, isolated current to the field device, and it passes the HART signal transparently in both directions.

The PR 9107A and PR 9107B differ in their approval and application details; both accept an analogue current control signal with bidirectional HART, output an isolated current signal to I/P converters, valves, positioners and indicators in the hazardous area, and are powered from 19.2 to 31.2 VDC, either through terminals on the DIN rail or from the PR 9400 power rail, which distributes power and a common fault signal to a whole row of modules without individual wiring. The detachable PR 4500-series display shows the signal and supports configuration. Protection is IP20 for cabinet mounting.

Applications are galvanic isolation, operation and control of field devices in hazardous areas across oil and gas, petrochemical, chemical, power, mining and process automation. For input loops from hazardous-area transmitters, see the PR 9116 universal converter.