Variable frequency pump signal to DCS
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This post was last edited by zhoudingshengs on 2024-1-22 at 11:32. Discussion: What signals from variable frequency pumps are required to be fed into the DCS?
The signals that variable-frequency pumps need to be sent to the DCS usually include the following: 1. Flow rate signal: Used to measure the flow rate at the pump’s outlet; this is typically measured by flow meters, with the data then transmitted to the DCS system. 2. Pressure signal: Used to measure the inlet and outlet pressures of the pump; it is typically measured by pressure sensors, with the data then transmitted to the DCS system. 3. Motor speed signal: Used to measure the speed of the pump; it is typically measured using an encoder or Hall sensor, with the data then being transmitted to the DCS system. 4. Motor current signal: Used to measure the motor current of the pump; it is usually measured through a current transformer, and the data is then transmitted to the DCS system. 5. Fault signal: Used to detect whether there is a fault in the pump; this is typically done through fault sensors, which transmit the signal to the DCS system. .
There is no fixed one; it depends on what information you need
Fault operation, remote indication, start/stop control?
The DCS is only responsible for stopping the pump; starting the pump should not be controlled by the DCS.
Commands to start/stop the pump, operation/fault signals of the pump, frequency setting/frequency feedback, and current feedback.
Depending on the requirements of your plant, it basically involves 3DI inputs for standby, operation, and fault conditions; 1AI for frequency feedback, and 1AO for frequency setting. If start/stop functionality is required, then 1DO or 2DO is used for that purpose. In some plants, DCS-based starting is not allowed, so a DO stop interlock is used instead.
Agreed, it depends on the requirements. Companies like ours also have local/remote signals (local control panels, remote DCS, switchable via selector switches), interlock stop signals, automatic switching signals for backup pumps (one in use and one as backup, with automatic switching), etc.