The Yokogawa DCS system control loop panel displays IMAN
Thread Content
What does IMAN mean on the Yokogawa DCS control loop panel? When IMAN is displayed, the system is unable to send a signal to the control valve for regulation. Does it mean there’s a problem with my line somewhere? The indications from the on-site locator are all normal.
It should be cascade control; it’s set to manual mode. The individual output works fine, but the cascade module isn’t functioning
By chance, I found out where the problem lay. During the debugging of another valve, after removing the wiring of the positioner, the direction of operation in case of a power loss was checked. Once the wiring was reconnected, the FIC controller of the DCS displayed IMAN, and it was not possible to restore it to its normal mode. The control panel of the FV shows normal operation, and it is able to control the valve. The manufacturer’s response was: “IMAN” means that the down side connecting function block is in MAN Mode; try to set the 713FV803 faceplate to CAS or AUT mode from the faceplate itself.
Change the cascade module from “MAN” to “AUT””
Change the cascade module from “MAN” to “AUT””
I manually initialize the status; in terms of the cascade loop, since the main loop is not set to automatic mode, the secondary loop should be in the CAS state. Normal operation: Set the main circuit to aut, and set the secondary circuit to cas! :)
What could be the reason for IMAN occurring in a single-loop system as well?