SEW Servo drive with plc M340

[Hakim Eng]

Hello guys,
Please i need help about SEW Servo drive controlled via SBus & Field Bus Modicon M340 PLC.
The problem is, when the motor reaches its desired position, the homming request still be on and the status word.0 ( motor is turning ) is sent to plc in a flashing manner (On/Off).

What could be the reason of the homming request even the target is reached ?

 

[RedSnake]

Hi,
Would need a little more info to be able to help.
What SEW drive is it ?
Are you driving it from the PLC program MOVI-PLC?
Have you used any manuell overide program for commisioning?
Have you requested homming?
What is the name of the signal you call homing request? AM_HOMING?
Or have you asked it to go to position with set speed ?

Best Regard A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Hakim Eng]

Hi,
I would like to thank you for your reply, and this is my situation


- SEW Movidrive MDX61B, programmed with IPOS.
- Fixed speed with a fixed target position.
-controlled via plc M340.using i/o scanning via ethernet.
- Homing means moving toward the target position ( when target position reached, homing = 0, and when moving, homing = 1).

- as a Hint, when using the Jog mode, everything works properly, but when using Automatic mode ( control words ), eventhough target position is reached, but the drive still looking for the home (stay moving with small displacement steps ).

- my question is, what should we do to prevent the motor from moving once target position is reached ?
My case, target position=1709.
i want the motor to stop at 1709 until next cycle is started.

Thank you so much for your help

 

[RedSnake]

Have a look at chapter 6.7 Modulo function if you are not already using it.

https://download.sew-eurodrive.com/download/pdf/11645415.pdf

BR A

 

[Hakim Eng]

Hi,
yeah i am agree with you, the homming is like the initial position, in my case i have a rolling chain with product on it, once it travel from initial position to target position it has to be re-initialised.means every time the motor turns 1709 and start again from zero.

i hope it can be understood.
Thank you so much.

 

[RedSnake]

Okay I understand.
I'm not sure that homing can be used that way if homing has the value 0 and the target position is 1709.
The drive should try to go back to 0 when you set homing.
But as I said, I'm very unsure here.
Does the operation have an external absolute encoder or is it possible?

A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[itsmoked]

Generally you need to home all drives when they get powered up. They are not happy until that is done. It may be the drive goes to the location asked (somehow) but is still complaining because it hasn't been homed.

Also, frequently the system isn't supposed to use "home" normally as a frequently visited location as that has additional motion control involved. Normally there is home then a location like '2' and then your target position '235' then you return to the '2' position not ever 'homing' again.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Hakim Eng]

Maybe we are confused using this keyword homing, just forget about it,
- a sin/cos encoder is connected to the DEH11B card of the servo drive.

Can i configure it in an openloop control ( neglect the encoder ) and just use a limit switch or a photocell to ensure that the product reaches the target to restart the cycle again ?

 

[RedSnake]

Have a look at chapter 6.7 Modulo function if you are not already using it.

https://download.sew-eurodrive.com/download/pdf/11...

BR A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Hakim Eng]

Thank you so much, i will check it soon.

 

[RedSnake]

If you are only going to transport one thing at a time from the beginning of the conveyer to the end, you probably only need something that detects that something has been put at the begining and that something has arrived at the end. Set Run and Speed, Reset Run and Speed when it arrives.

I guess it depends a bit on how accurate the position must be at the end.
But often things have a tendency to slip on chain tracks so a photocell at the end of the conveyer is probably a safer solution than just going on pulses.
I would probably always have a photocell/sensor at the end even if I used an encoder for the actual positioning as extra security.

If you want to transport several things at the same time on the conveyer, positioning in steps, it will be a different thing.

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[RedSnake]

Come back and tell us how it works out for you

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[Hakim Eng]

yeah i will,
Currently i am in holidays, once i get back i will return you the feedback