What kind of command or signal PLC gives to the VFD to make the motor run ?

[dineshdeshmuk]

What kind of command or signal PLC gives to the VFD to make the motor run at a particular speed ?

 

[chuckey]

Most VFDs use an external pot to adjust the speed, so I guess a suitable voltage source would fool the VFD into thinking it had an external pot.
Frank

 

[dineshdeshmuk]

what voltage source analog or digital ?

 

[dineshdeshmuk]

Besides speed controlling what else controlling does the PLC does to VFD ?

 

[dineshdeshmuk]

What things a PLC control of a VFD ?

As far as i know , the PLC sends AO signal from its AO contact to the VFD' AI contact for the speed reference.

the PLC also send a DO signal from its DO contact to the VFD' DI contact for the run command.

the PLC behaves a master to the VFD

Other than these things what other else things a PLC control of the VFD ?