Regarding the motor’s IO points
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For the motors we have been working on, there are two DOs for closing and tripping, as well as three DIs for the operating status, fault status, and remote/local switching status. I would like to ask everyone: which points do you usually use?
We have only two DOs and one DI: one for start/stop, and one for operation feedback; it can be controlled both remotely and locally
Our company’s standard motors are equipped with two DOs for starting and stopping, as well as one DI for operational feedback. If such a motor is driven by an inverter, an AO output is usually provided to the inverter to control its frequency. To accurately determine the motor’s operating current, an AI is added at the DCS side to serve as a current feedback mechanism. Our factory uses only one AO to control the frequency. The inverter output relay can be set to provide a fault output; by connecting the normally open contact, this becomes the fault output, and the DCS receives a DI signal. Our company does not use DCS; instead, we employ normally closed contacts that are connected in series in the control circuit of the contactor. This allows us to cut off the output of the valve contactor when the frequency converter fails.