Siemens MM440 Inverter Drive & 1746-NI04V

The Siemens manual shows the use of an electric pot as the appropiate connection for the analog voltage input but if you are using a PLC for you speed reference than I'm thinking thats enough and the pot shouldn't be necessary (the run from PLC to inverter is not far)

Am I correct in thinking that a straight connection between my PLC card and the Analog inputs is fine or do I still require a pot and follow the Siemens recomendations.

Would of asked Siemens but there customer support is lacking.

The diagram you refer to is just an example how to provide a 0-10V reference with a simple potentiometer.
What the analog input needs is either 0-10V or 0-20mA.
The 0-10V or 0-20mA is decided by the switches right next to terminal 18.
Switch 1 and 2 are for analog input channels 1 and 2 respectively.
OFF = 0-10V
ON = 0-20mA

I suggest you chose 0-20mA for you analog output from the PLC.

Thanks for the help just 7 weeks out of school still feeling out the industrial world little nervous to make a mistake.

Normally I would use current because of the voltage drop but we are installing a Siemens drive to replace an obsolete unit and trying to keep it simple by not changing the PLC program and this function was voltage on the old drive.


Thanks again.