Using MAPC instruction to control PF527 as master slave

[themoonlight 0]

Hi there, 

I have two PF527 connected to two motors and encoders and I want to control them as master and slave both run at the same speed for some points then the master increase its speed and slave should keep its speed or dcrease at another points.

I was reading through MAPC instruction and understand that i can use this instruction to control PF527 as master slave.

The explination of this function is very dry and couldnt understand how this function work exactly.

Can anyone help and explain it to me how the this instruction works?

Thanks for your response in advanc.

 

 

 

[JRoss 84]

The MAPC is a powerful, but complicated instruction unless you use it frequently. I use it only if I need one axis to do a specific position profile following another axis.

Do you need a position profile, or do you just need speed matching? If you're just speed matching them, then here's my thought. Create a Virtual servo axis, then use MAG instructions to gear both 527 as slaves to the Virtual axis. When you command the virtual master to run, the 527 will follow. Then you can define different gearing ratios for each 527 when you want them to run at different speeds.

[themoonlight 0]

Thanks for prompt response. well I need to create position and speed profile. at certain position the speed will change accordingly! 

[kaiser_will 65]

Page 100 starts a lab example of (2) PF drives, setup as master-slave, with a MAPC block controlling them.  https://www.rockwellautomation.com/resources/downloads/rockwellautomation/pdf/events/raotm/sessions/manuals/L15-IntegratedMotion.pdf

What is your speed command feedback to the 1st VFD?

[themoonlight 0]

Jog command

 

[kaiser_will 65]

You should be good to go with the MAPC instruction to drive a pair of PF 527 VFDs as a group.

Page 162 has detail about the MAPC command; Master Reference would be the speed command.  http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/motion-rm002_-en-p.pdf

Page 170 has detail about status/control bits.  Make sure your logic properly controls the state of these bits as you can exhibit an astable condition if these bits are not in the proper state.   If you command the MAPC block to do something and nothing happens, there is a good bet that your control bits are not in the proper state. http://literature.rockwellautomation.com/idc/groups/literature/documents/rm/motion-rm002_-en-p.pdf