Servo Axis reverse direction

Hello everyone,

I'm currently working on software which has to be mirrored. The simple way would be to reverse the direction of the servo axis then the software would be unchanged. I'm using a L71 plc from rockwell. I have found something like Motion Run Hokup Diagnostics (MRHD)
Motion Apply Hookup Diagnostics (MAHD) but i don't know if it actually starts to move the axis or if i can simply reverse the direction of the servo axis. Can anyone give me some info on this? And how to use it maybe?

Kind Regards,


Bob

open the axis in the and perform the feedback and hookup tests - this is where you can reverse the motor direction without changing the wiring
The test open a popup with a tickbox to reverse direction

If this is a regular occurrence then this solution is not the best

I've never used the MRHD and MAHD instruction pair, but it appears that it is just a programmatic way to do as MichaelG describes manually in the Hookup tab of the servo axis properties. I've always setup my axes using the manual hookup test, as it usually is just a one-time set it and forget it deal.

If you are just copying code to an otherwise identical but opposite handed machine, then I would say why not just keep the same code but run the hookup test and set the rotation opposite there (or just set "Drive Polarity" to negative instead of positive in the Hookup tab)?

But as Michael said, if this is a frequent change on a piece of equipment, where you just want everything to move backwards, then you may need to look at mirroring your code based on whatever condition causes the machine to need to run backwards...just depends on how your motion instructions are set-up that determines how simple or complex this might be.

my understanding is that MRHD and MAHD instructions are only used for testing and tuning

MichaelG said:

open the axis in the and perform the feedback and hookup tests - this is where you can reverse the motor direction without changing the wiring
The test open a popup with a tickbox to reverse direction

If this is a regular occurrence then this solution is not the best

Click to expand...

Hello all,

First of all thank you for your reactions. Second i would like to ask you why this is not a good solution? Its just reversing it right so what is so bad about just changing the polarity?

Kind Regards,


Bob

I don't have a great understanding of the technical side of what you're doing here, but I think Michael's point is that if this is something your operators want to reverse every other day, you don't want to have to call the technician and get him to do it on a laptop every time. You want some way for the operators to be able to do it themselves with a switch or a HMI login.

If it's something that happens every couple of months, not such an issue. It's just about operator friendliness I think.

ASF said:

I don't have a great understanding of the technical side of what you're doing here, but I think Michael's point is that if this is something your operators want to reverse every other day, you don't want to have to call the technician and get him to do it on a laptop every time. You want some way for the operators to be able to do it themselves with a switch or a HMI login.

If it's something that happens every couple of months, not such an issue. It's just about operator friendliness I think.

Click to expand...

exactly - even though I would use a operator accessible (ie programmed) if the direction change time was months.

SSJVegetto said:

Hello all,
First of all thank you for your reactions. Second i would like to ask you why this is not a good solution? Its just reversing it right so what is so bad about just changing the polarity?

Click to expand...

Getting out my laptop to regularly change a setting for an operator is
a) a waste of my time.
b) Dangerous for the company if I am the only one who knows how to make the change (eg on holidays, sick or quit)

MichaelG said:

exactly - even though I would use a operator accessible (ie programmed) if the direction change time was months.



Getting out my laptop to regularly change a setting for an operator is
a) a waste of my time.
b) Dangerous for the company if I am the only one who knows how to make the change (eg on holidays, sick or quit)

Click to expand...

Ok well in this case its just about a machine that is either going to run in reverse or in forward polarity its not changed during operation at all since the machine is simply mirrored. So therefore i would ask, this is a safe procedure to do it then i guess?

SSJVegetto said:

Ok well in this case its just about a machine that is either going to run in reverse or in forward polarity its not changed during operation at all since the machine is simply mirrored. So therefore i would ask, this is a safe procedure to do it then i guess?

Click to expand...

Yes. This is what I was saying back in post #3. Just set the servo to the opposite polarity in the Hookup tab.

What we all were saying was that if the rotation needed to change semi-frequently, then you would want to make the change programmatic, via an HMI and an SSV to the DrivePolarity attribute.

bmacattack33 said:

Yes. This is what I was saying back in post #3. Just set the servo to the opposite polarity in the Hookup tab.

What we all were saying was that if the rotation needed to change semi-frequently, then you would want to make the change programmatic, via an HMI and an SSV to the DrivePolarity attribute.

Click to expand...

Well basically i would want to make an option for the admnistrator that when the software is downloaden the choice is there to set the machine into the other direction. But i will keep this in mind. Thank you all for your time and information.