In conventional applications, pumps or fan should be run at full speed, then pressure or flow should be controlled with a control valve. Hence some energy will be wasted when you are throttling control valves. One of the major usages of VFD, is cost saving through energy saving. At WEG/VJP Cost Savings Knowledge Hub learning session, we will discuss a unique angle of cost saving which is capital saving by removing some instrumentation and control valves and by utilizing VFD with built-in PLC.
If you replace one VFD with a built-in PLC, you are removing extra components that are no longer needed, such as; the control valve, independent PLC for throttling, additional sensors / transmitters for motor speed, torque, flow element / transmitters, cabling, junction boxes, installation stands for the transmitters and sensor. In addition, to some other parameters such as motor speed, motor torque, motor current which are freely available when SoftPLC code is used. There is a SIL2 IEC 61508 STO relays that can stop VFD in case of requirement for Shutdown command, from safety sensors such as vibration protection system.
At WEG/VJP Cost Savings learning session, we will discuss a few applications that can utilize built-in SoftPLC with VFD solution, such as:
- Header pressure control with Multi Pump Control: Flow or pressure will protect the pump by tripping the pump on PAHH, FALL or PALL. It can be done with one or more VFD. For zero flow control, you just need to set a protection in SoftPLC code if the torque percentage is less than a value (e.g. 20%) and motor is at certain speed. All of the auxiliary pumps such as lube oil pump can be programmed in VFC softPLC. Hence costly control valves, flow transmitters can be removed and the same for additional hook-up, cables, JB, tray, etc.
- Control of air flow/ pressure with Fan: If built-in SoftPLC with VFD is used, you can connect the pressure or flow sensor to VFD and set internal PID controller to control the fan speed with respect to the set pressure or flow rate. As VFD has DI, AI, you can have a lot of interlocks for safety and similar to pump application, you can detect the fault with the internal parameters of VFD which could be more effective in compare to some vibration protection sensors. Differential pressure of filters can be connected to VFD with SoftPLC and get respective alarm or fault trip as required.
Learn more on how to increase productive while reducing energy cost by removing some instrumentation and control valves and by utilizing VFD with built-in PLC. See you at WEG/VJP Cost Savings Knowledge Hub Learning Session!