driving a freq var by a plc

juan · May 12, 2003

I was wondering if its possible to send certain code from the plc program to the frequency variator in variable words, in that way I use one code to drive the motor(by the freq. var)in the left direction and another code for right position. By code I mean the values in the variable words. If this is possible are there standard values? i'm using the Siemens micromaster.

Thanks

Tom Jenkins · May 12, 2003

Probably yes, but you hae to have a VFD (Variable Frequency Drive) or other device and a PLC that both have the same communications protocol and serial configuration. For example, if the VFD or control device has a serial port with Profibus cpability and the PLC has a Profibus port, the PLC can send and recieve commands and data from the VFD. You need to configure the port address and communications parameters in both devices, and you need a list of the memoryt locations in the VFD from the manufacturer that identifies the locations in the VFD memory of the data you are interested in.

juan · May 12, 2003

Which values

There is already a connection, but I don't know which values to drive the both directions. The serial port is already established and in use.

JRW · May 12, 2003

Juan,
Just buy the Siemens "Toolbox" option. This option integrates into MicroWin. It will give you the function blocks for the USS protocol.
It is very easy to use.

JRW · May 12, 2003

I understand your question now- what micromaster are you using?
MM4 or the 6SE3x model?

juan · May 12, 2003

toolbox??

Is this toolbox a extra hardware device of is it a software toolbox? Is this expensive an which possibilities are there available? Is this the only possibility?

juan · May 12, 2003

sorry

I didn't saw your last reply, I'm using the 6SE3213 type

JRW · May 12, 2003

102193a

Is the drive already running and you just need the control word
values for reverse? or is this a new application and you are
trying to run a micromaster drive?

juan · May 12, 2003

already running

There is already one direction running and we want to establish to other one. At the moment we can go to the other side but ...
In the attached file the 'V' is the direction at work but the 'k' has to be improved

juan · May 12, 2003

sorry

This file is quiet big, but the most important things about this topic are in INT0(V,K), INT3,5(resp V,K), SUBR3

Thanks a lot!

JRW · May 12, 2003

Here's a sample of USS using the toolbox.
Basically bit 14 (start with 0 through 15) of the control word needs to be ON
So-
047F-Run Forward
047E- Drive Stop
147F- Run Reverse
147E- Drive Stop

juan · May 13, 2003

drive stop

This is the way how we can stop at any moment, but if we want to stop when the current value equals to the preset value is it the same way to stop?
Sorry I keep on asking, but it interests me a lot

Thanks Juan

driving a freq var by a plc

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