What is "Negative limit input" of servo

[vanquangtk]

Hello every one

 I got a trouble with Omron Servo, when I write instruction MC_Move Absolute in sysmac studio . an error appear to say "negative limit input was on".

Do you know what is "negative limit input" and how I can find it.

Thank you

[89GTA]

There is an input on the servo drive configured as an overtravel (limit). You either need to install an overtravel limit switch/sensor and wire it to the input, put a jumper wire on the input, or alter the input parameters so that it does not need to see a limit switch. More than likely you will need to do this for the positive limit as well.

[vanquangtk]

Just now, 89GTA said:

There is an input on the servo drive configured as an overtravel (limit). You either need to install an overtravel limit switch/sensor and wire it to the input, put a jumper wire on the input, or alter the input parameters so that it does not need to see a limit switch. More than likely you will need to do this for the positive limit as well.

I connect the servo with NJ through Ethercat, so I don't know where I should find the switch/sensor, actually I don't install any sensor with servo . Where should I alter the input parameters in Sysmac

[Michael Walsh]

Set Pn401.0, Pn401.1, Pn401.2, Pn402.0, Pn402.1 and Pn402.2 all to 0 (Disabled) as shown below:

 

You will have to cycle power to the drive in order for the changes to take effect.

[vanquangtk]

Just now, Michael Walsh said:

Set Pn401.0, Pn401.1, Pn401.2, Pn402.0, Pn402.1 and Pn402.2 all to 0 (Disabled)

Can you tell me the use of these parameter, I'm just begginer with NJ so I really don't understand these parameter at all.

Are they similar to internal relay of Mitsubishi PLC

[Michael Walsh]

They define two of the digital inputs on the servo drive (CN1 connector).  By default, they are set to be used for a positive overtravel limit input and a negative overtravel limit input.  These are usually two limit switches that keep the servo motor mechanicals from crashing into the end of travel for each direction.  If you are not using these switches, setting the parameters above to 0 will disable the functionality.

[vanquangtk]

Just now, Michael Walsh said:

They define two of the digital inputs on the servo drive (CN1 connector).  By default, they are set to be used for a positive overtravel limit input and a negative overtravel limit input.  These are usually two limit switches that keep the servo motor mechanicals from crashing into the end of travel for each direction.  If you are not using these switches, setting the parameters above to 0 will disable the functionality.

I also get another similiar problem, but this time with MC-Homing, error said , two limit signal are on, how can I resolve the problem

[Michael Walsh]

Do you have the Positive and Negative Limit Inputs logic reversed?

It should look like this (Other Operation settings under the axis setting):

[Crossbow]

As Mike said (fairly clearly as well) if you are not wiring the limit switches to the drive (see the manual for the servo amplifier) you need to disable those inputs in the servo parameters.  Factory default parameters are for a normally closed end of travel switch at each end of the servo's travel.

These are nothing like internal relays in a Mitsubishi, these are parameters inside the actual servo amplifier.

To set them, in the Multiview Explorer, go under EtherCAT, find the amplifier, click the arrow to open, and then double click on Parameters.  To be able to change them, right click on the amplifier and select Online.  This will go through the existing connection to the NJ across the network so you don't need to plug in directly to the amplifier.

If you need more assistance than that, you may want to review the free online training on Omron's website, or the NJ Motion Startup Guide (manual W514).

[vanquangtk]

Hi guys, is there anyone here know how to create and read data output from FH sensor in Sysmac. I read the manual of omron but they are so complicated for me.

Maybe I need an example for that. Do anyone have experience in it? Thank you.

[Michael Walsh]

On ‎5‎/‎21‎/‎2016 at 1:30 PM, vanquangtk said:

Hi guys, is there anyone here know how to create and read data output from FH sensor in Sysmac. I read the manual of omron but they are so complicated for me.

Maybe I need an example for that. Do anyone have experience in it? Thank you.

Why would you post this here?  This thread is about servos...

[vanquangtk]

1 hour ago, Michael Walsh said:

Why would you post this here?  This thread is about servos...

I am sorry for this. I intended to post it in a new thread. But I have many stuff small question like that about omron, NJ and FH. And I think it woul be better and convienient to post all of them in one thread

[Crossbow]

No, a thread is meant to be one topic.  If you have non-related issues, you should create new threads.  That makes it easier for others to search them in the future.  Besides that, if the title is something I don't have knowledge of, I won't bother reading the post.  I bet many others are the same.  Then we would miss the chance to assist you.

[vanquangtk]

41 minutes ago, Crossbow said:

No, a thread is meant to be one topic.  If you have non-related issues, you should create new threads.  That makes it easier for others to search them in the future.  Besides that, if the title is something I don't have knowledge of, I won't bother reading the post.  I bet many others are the same.  Then we would miss the chance to assist you.

Oh, I see it now. Thank you so much for helping me.With help of you and people here , I start know how to control servo through NJ

[vanquangtk]

Does any one know how I can be sure that my servo stopped completely after a move instruction

[Michael Walsh]

You could look at the bit AxisName.Details.Idle It is no when processing is not being performing.

Look at the variable that is created when you add an axis.  It is of type _sAXIS_REF.  You can find details in the NX-Series CPU Unit Motion Control User's Manual that is installed in the Sysmac Studio folder of the start menu.

[vanquangtk]

45 minutes ago, Michael Walsh said:

You could look at the bit AxisName.Details.Idle It is no when processing is not being performing.

Look at the variable that is created when you add an axis.  It is of type _sAXIS_REF.  You can find details in the NX-Series CPU Unit Motion Control User's Manual that is installed in the Sysmac Studio folder of the start menu.

Can I use the bit  AxisName.Status.Ready for it

[Michael Walsh]

Yes, that is a better bit. 

The best solution might be to use the DONE bit from the Function block that issued the movement command.

This is the done bit from the MC_Move FB:

[vanquangtk]

I got a trouble with drive servo, it alarm overload error with error code is 034E200. I tried to reset that error by functions: Reset MC-Error or Reset-PLC Error.

But I failed, the only way I can do to make it disappear is using reset button in troubleshooting tab of Sysmac Studio.

Can anyone tell me the reason of it and how I can fix it completely, thank you

[Michael Walsh]

Use MC_Reset to reset the servo drive, then use ResetECError to reset the EtherCAT error.

[vanquangtk]

Just now, Michael Walsh said:

Use MC_Reset to reset the servo drive, then use ResetECError to reset the EtherCAT error.

I did them all, but it didn't word

Do I need to take MC-Reset before Reset ECError

[Michael Walsh]

Just now, vanquangtk said:

I did them all, but it didn't word

Do I need to take MC-Reset before Reset ECError

Yes.  The error on the drive is causing the EtherCAT error.  So, trying to reset the EtherCAT error before resetting the drive will not work.  First reset the drive, then reset EtherCAT.

[vanquangtk]

Just now, Michael Walsh said:

Yes.  The error on the drive is causing the EtherCAT error.  So, trying to reset the EtherCAT error before resetting the drive will not work.  First reset the drive, then reset EtherCAT.

Sorry do I must take MC-Reset or MC-Reset Error, I got this error so often , may you tell me the way to prevent it. Thank you

[Michael Walsh]

I cannot find the error code that you provided.  What is the error code on the front of the drive? 

If it is a standard overload, Overload errors are caused by excessive torque.  Either something is wrong mechanically with your system, or your motor is not sized properly.  I guess that the program could be incorrect also, if it is driving the servo too far and hitting a stop (but this is still a mechanical issue causing too much torque). 

If it is a regeneration overload, then you may be regenerating too much voltage back on to the DC bus.  This usually happens in vertical applications, or if you are trying to stop too quickly.  If you have a vertical application, you may need to add a regeneration resistor to burn off the excess regeneration voltage.  If you are just trying to decelerate too quickly, then you can make the deceleration less aggressive.

This is one way that you might use the combination of first MC_Reset and then ResetECError:

The first rung issues the MC_Reset command if the drive is in alarm and the safety is OK.  Once the drive is no longer in the alarm state, the second rung resets the EtherCAT error.  This is just a quick example, you may want to add more conditions to these rungs.

[vanquangtk]

Just now, Michael Walsh said:

I cannot find the error code that you provided.  What is the error code on the front of the drive? 

If it is a standard overload, Overload errors are caused by excessive torque.  Either something is wrong mechanically with your system, or your motor is not sized properly.  I guess that the program could be incorrect also, if it is driving the servo too far and hitting a stop (but this is still a mechanical issue causing too much torque). 

If it is a regeneration overload, then you may be regenerating too much voltage back on to the DC bus.  This usually happens in vertical applications, or if you are trying to stop too quickly.  If you have a vertical application, you may need to add a regeneration resistor to burn off the excess regeneration voltage.  If you are just trying to decelerate too quickly, then you can make the deceleration less aggressive.

This is one way that you might use the combination of first MC_Reset and then ResetECError:

The first rung issues the MC_Reset command if the drive is in alarm and the safety is OK.  Once the drive is no longer in the alarm state, the second rung resets the EtherCAT error.  This is just a quick example, you may want to add more conditions to these rungs.

Thank you so much for help me, I will try to find exact code error I got tommorow when I work back. It seem that I made the servo move too fast in a short distance