P & I D - GE Baker Hughes Masoneilan SVI FF Installation And Operation Manual

P & I D
Figure 50 shows, in schematic form, the physical devices and indicates the measurement and
control functions that reside in each device. The flow of control information between devices is
indicated by dashed lines.
The coolant flow control valve, FV 101, has a PID control function block, one DI block
and an Analog Output block (AO), all located within the valve positioner. The DI block
can set either a high limit, a low limit or both the high and low limits.
The coolant flow transmitter, FT 102, has only a transmitter function. It has Analog
Input function block (AI) implemented in its firmware.
The temperature transmitter TT 103 contains one Analog Input block and a PID block.
The PID blocks in TT 103 and FV 101 devices are scheduled to work in cascade as
shown in Figure 51. The AO block in the FV 101 receives the output from the FV 101 PID
block and via the transducer block transmits it to the control hardware of the valve.
The condensed fluid flow control valve, FV 201, has a DI block and an Analog Output
block, all located within the valve positioner. Liquid level is controlled by a remote
controller LC201 to demonstrate Remote Cascade operation.
The level transmitter LT 202 includes an Analog Input block. The flow controller in LV
201 receives the process measurement from level transmitter LT 202. The PID control
regulates the valve LV201.
The DI block ZSL 101, depending on the wiring, serves as low and/or high stem position
limit switches in the control valve positioner FV 101.
The DI block ZSL 201, depending on the wiring, serves as low and/or high stem position
limit switches in the control valve positioner FV 201.
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BHGE
Figure 50 Piping and Instrumentation Diagram
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