Drive Control over Profibus.

Hello guys,

In the past 6 months you helped me a lot and now I ask for the help again.

I have some drives controlled on profibus from PLC with a control word.

the PLC function used to control is more or less doing so : Send bit 0 to preset the drive - aka close the contactor. if I have No interlocks from other things like emergency relays then the function will enable bit 3 "Enable operation" - start/stop basically. After I send back status Magnetizing completed the plc sends me Reference enable or speed enable on BIT6.

this is the start part. now for the stop, it is a little bit different because it is not removing off(preset)1 for the drive, it is setting reference 0 and removing bit3, and it should also remove bit 6 but i am not sure if it does. And I set a minimum speed in the drive of 70%.

My question ii : Is the drive supposed to keep the motor running after I remove bit 6 which is corresponding to parameter p1142? Can it keep running at minimum speed even if RFG is no enabled?

Please help, this is hurting my brain now.

The PI (organisation for PROFIBUS and PROFINET) defines a PROFIdrive profile. In this the control word 1 is defined. You will first have to set several enables and then give the ON-command.

Generally you have to send 047E to set all enables and then switch to 047F to switch on the drive.

If the enables and the ON command comes at the same time, the drive will not switch on! 

Download the manual at https://support.industry.siemens.com/cs/ww/en/view/94020562 and look in chapter 7.3.1.1 . Even if you have a other drive, the Bits 0 to 10 are identic.