Hi everyone,

I'm new to Siemens and I'm trying to enable a G120VFD using SINA_SPEED on Tia Portal v17. The PLC I'm using is an S7-1200 PLC.

I've wired an ON and OFF Push Button to the PLC and 3 x 24V Digital signals to the PLC inputs to control the VFD speed. Once online I've observed that the Speed SP gets set as per the combination of the 3 x Digital bits seen in the ladder logic attached. However an output on the SINA_SPEED block viz. "AXIS ENABLED" remains FALSE regardless of the state of the input "ENABLE AXIS". At the same time an output on the SINA_SPEED block "ERROR" goes High as well.

I'm able to see the speed on the VFD screen but can't get the VFD to Run despite Enabling it.

Can someone please suggest a way ahead.

Thank You,

Anthony

the status of the SINA_SPEED FB says "8402" which means switching on is inhibited on the drive side. 

My guess would be Safety -> is STO selected on that drive? If yes the drive cannot be switched on. I recommend to go online with the drive and check its status.

Hi Rob,

Thanks for your reply. I missed adding that I haven't connected both incoming and outgoing 3 phase feed to the VFD. I've hooked up a 24V DC supply to the Control Unit (CU240E-2PN) and the PLC to validate comms between the two devices. 

Do you reckon the absence of a 3 phase supply would be the cause of this error?

Cheers,

Anthony

Hi everyone, 

I solved this months ago, but thought of posting it here in case someone new to Tia Portal also faces this problem.

I was unable to drive the motor using the SINA SPEED Block because I missed writing 003F to the config axis terminal of the SINA_SPEED block.

If you ever face  a problem please check if you've done this and also ensure that the RUN.ENABLE AXIS bit of the same block is pulled high by your program.

Hope this helps.

Cheers.