Altivar 31 and SLC500

Good day to all. I'm installing a new motor and control and am a little confused about how to control VFD with SLC500. All I have are 120VAC and RTD output modules. If I understand the installation manual for the Altivar, I must use a dry switch (or contact) or 24VDC. Has anyone here set up an Altivar drive with a SLC500? All i'm controlling is a push-air blower, one speed, so just a simple on/off situation. Problem is the 120VAC output from PLC to turn it on and off. Thank you for the help. Oh, and by the way, SLC500 is interfaced with MMI, which is how operator will turn the blower on and off.

ceilingwalker said:

If I understand the installation manual for the Altivar, I must use a dry switch (or contact) or 24VDC.

Click to expand...

Just use a relay with a 120 volt coil (powered on and off by the PLC) and use a contact from said relay as your contact for the VFD.


Edit: what is a RTD output module?

milldrone said:

Just use a relay with a 120 volt coil (powered on and off by the PLC) and use a contact from said relay as your contact for the VFD.

I was trying not to add another relay. Too many relays is the reason why I installed the PLC. I will just have to buy a relay module I guess. Thanks for the input.


Edit: what is a RTD output module?

Click to expand...

Oooops, my bad. It's an RTD input module.