# My first Post



## eng_bhs (May 27, 2011)

Hello guys, 
Im working with Baggage handling system that is running with S7-400 siemens plc and we are using "SEW's Frequency Inverter to control the operation of some motors. I have a problem with one frequency inverter from MOVITRAC 07 series. when the motor is running the inverter is giving the correct rpms but when the motor stop the inverter does not show stop or zero rpm instead its showing 1 rpm which means that supply is still reaching to the motor and its making the motor overheated and by time the motor windings is gone. I tried to replace the inverter and edit the parameters settings but still I have the same problem. Is there anyone who could have an idea about this issue. I want to make the inverter show stop or zero rpm when the motor stop.
please i need a quick help for my problem. Thank you guys and waiting for your help.


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## Wirenuting (Sep 12, 2010)

eng_bhs said:


> Hello guys,
> Im working with Baggage handling system that is running with S7-400 siemens plc and we are using "SEW's Frequency Inverter to control the operation of some motors. I have a problem with one frequency inverter from MOVITRAC 07 series. when the motor is running the inverter is giving the correct rpms but when the motor stop the inverter does not show stop or zero rpm instead its showing 1 rpm which means that supply is still reaching to the motor and its making the motor overheated and by time the motor windings is gone. I tried to replace the inverter and edit the parameters settings but still I have the same problem. Is there anyone who could have an idea about this issue. I want to make the inverter show stop or zero rpm when the motor stop.
> please i need a quick help for my problem. Thank you guys and waiting for your help.


Kind of similar to a siemens to drive issue we had. Turned out to be the program in the siemens PPCL did not have a "stop" command line It kept scanning for a run and the program looped anticipating the average run. So it would idle at about 10 Hz.

Welcome to the forum. Lots of good people here that might be able to help you better.


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## Jlarson (Jun 28, 2009)

So you replaced the drive and the problem persisted? 

What type of control signal are you sending the drive?


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## eng_bhs (May 27, 2011)

Wirenuting said:


> Kind of similar to a siemens to drive issue we had. Turned out to be the program in the siemens PPCL did not have a "stop" command line It kept scanning for a run and the program looped anticipating the average run. So it would idle at about 10 Hz.
> 
> Welcome to the forum. Lots of good people here that might be able to help you better.


@wirenuting: i was doubting the same and i will check i will try to check the program. Thank you


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## eng_bhs (May 27, 2011)

Jlarson said:


> So you replaced the drive and the problem persisted?
> 
> What type of control signal are you sending the drive?


@Jlarson: yes i have changed the drive but still I'm getting the same problem. i did not get what you mean about the control signal. the drive is controlled by siemens s7-400 plc


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## Jlarson (Jun 28, 2009)

eng_bhs said:


> @Jlarson: yes i have changed the drive but still I'm getting the same problem. i did not get what you mean about the control signal. the drive is controlled by siemens s7-400 plc


Like is the PLC sending it a 4-20mA signal, 0-5 volts, 0-10 volts, RS-484 modbus, Ethernet? How is the PLC telling the drive what speed to go.


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## eng_bhs (May 27, 2011)

Jlarson said:


> Like is the PLC sending it a 4-20mA signal, 0-5 volts, 0-10 volts, RS-484 modbus, Ethernet? How is the PLC telling the drive what speed to go.


@Jlarson: its 0-10 Volts.


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## Jmohl (Apr 26, 2011)

Siemens step7-400 with SEW eurodrive and Movitrac? Nice but :whistling2:$$$$.
Most of the stuff that I worked on that had that equipment in it was Euro. Most U.S. stuff is A/B, some Toshiba, GE Fanuc, etc.... Totally different programming structure and all.


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## Wirenuting (Sep 12, 2010)

Siemens bought out TI back in 2000-ish. 
The PlC does not use the PPCL programing language. But the PLC might have a siemens interface in the drive. 
Add the 3 together and it runs like poop. 
If the 0-10 is correct I would be leaning towards a bad sub-routine or programming loop. 
We use Siemens alot at work and their automation products always have problems interfacing with equipment. Landis & Guyers was bought by siemens in 2000 also. It's their program.
Powers Process Control Language. 
It's a C++ sytle. 
The PLC is just ladder logic isn't it?


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## Jmohl (Apr 26, 2011)

Step seven IIRC is functional block programming but I think you have the option of Ladder, BOOLean(why I can't fathom) and visual basic..... Kinda hard to get used to their conventions having worked A/B mainly.


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## Jlarson (Jun 28, 2009)

eng_bhs said:


> @Jlarson: its 0-10 Volts.


Did you but a meter on that signal and see how it behaves when the PLC tells the drive to stop?


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