Hi 

I am using a VFD i want to convert it to position control but in TIA portal there is no output configuration to control direction of motor (forward & backward) 

is anyone has an idea how to do it ?

Note: my VFD dosnt support inversion of direction by -10v 10v it uses digital input for forward and backward 

Hi,

you could use this: https://support.industry.siemens.com/cs/de/en/view/109773400/124312217739

Then manipulate the analog setpoint from the technology object within OB MC-PostServo, in order to have the right signal, as well as direction bits which you could directly generate yourself based on the analog setpoint value that comes from the TO.

Regards,
daviso

Hi 

Thanks for answer 
i read how to create MC-PostServo but i couldn't understand how to do it 
could you make a simple example to get an idea 

What exactly is the issue?

Basically you only need to add the OB MC-PostServo (like you add any other OB), then in the OB process the analog setpoint from the TO as you want / need, and from this setpoint generate your direction bits (simple compare function). Then write the values you generated to the process image, and from the program side this is it.

Just ensure at the module to which you write the setpoint and direction bits, that this is assigned to the process image of OB MC-Servo, so that the values you write into the process image in OB MC-PostServo get automatically written to the device.

There isn't really something special about it, basically this is just normal programming and taking care of the process image.

Regards,
daviso

Hi 

I am created MC-PostServo but i dont undurstand how to process analog set-point from TO & How to set direction digital output

could you take a screen shot 
Thank you

C'mon...

You connected the technology object to a PLC-tag. To this the TO provides the analog setpoint value.

What do you want?

-> generate direction bits and send them to the drive

How to do it?

-> process the PLC-tag to which the TO writes the analog setpoint. This is simple processing of analog values. Then just use a compare on this value, so that you generate the direction bits based on the result of this compare.

Really, this is neither something special, nor something very advanced. I'm sorry to say, but it really is only processing of one value, doing a compare on this, and based on the compare result you set two bits.

Regards,
daviso

Thank you for help it's worked for me 
Another issue is that when i move the motor from commissioning panel it workers fine  

but when i use user program it give me this Error 

I read the help but i don't understand what it means 

Is the PLC tag to which the TO's actor is connected really pointing to an address of an existing module?

My guess is, that you have connected the TO to some PLC-tag that does not point to existing hardware, and therefor you might get this error message.

Regards,
daviso