Can A Control Block (e.g. Pid) Be Inserted In A Transmitter Instead O

1.	Can A Control Block (e.g. Pid) Be Inserted In A Transmitter Instead Of In A Control Valve? If So, How Will Performance Be Affected?
Answer» Yes, it CERTAINLY can. There isn’t much difference in performance – there is one extra message per cycle, to balance the PID output value to any limits imposed by the Analog Output Block in the valve positioner (to avoid integral wind-up). In a cascade control application, it is quite likely that the primary PID will be located in the transmitter for the primary variable. Should an I/P converter be built into the (fieldbus compatible) control valve? If not, how would an I/P (from a different VENDOR) be tested as interoperable There really is no “I/P converter” any more. I would expect the “digital-to-P” FUNCTION to be built into the fieldbus valve controller, as LONG as the valve itself remains pressure-actuated. The controller might or might not be physically MOUNTED with the valve itself. (It would probably need position feedback from the actual valve stem.)

Can A Control Block (e.g. Pid) Be Inserted In A Transmitter Instead Of In A Control Valve? If So, How Will Performance Be Affected?

Answer»

Yes, it CERTAINLY can. There isn’t much difference in performance – there is one extra message per cycle, to balance the PID output value to any limits imposed by the Analog Output Block in the valve positioner (to avoid integral wind-up).
In a cascade control application, it is quite likely that the primary PID will be located in the transmitter for the primary variable.
Should an I/P converter be built into the (fieldbus compatible) control valve? If not, how would an I/P (from a different VENDOR) be tested as interoperable
There really is no “I/P converter” any more. I would expect the “digital-to-P” FUNCTION to be built into the fieldbus valve controller, as LONG as the valve itself remains pressure-actuated. The controller might or might not be physically MOUNTED with the valve itself. (It would probably need position feedback from the actual valve stem.)