Communication delay between PLC & robot

[DonNH]

NX1P2 PLC & LD250 AMR --

When the AMR reaches a specified goal, it sends an ARCL message over the wireless network.

The PLC sees this message and immediately sends a command back to the robot to go to the next goal.

I've looked at many of the logs from the robot, which show when the ARCL message is sent, and also when the response is received.

Typically it's about 0.3 seconds between these log entries.

A while back I was seeing delays in response up to about 8 seconds, especially in an area with poor wifi signal.

A few days ago, the robot seem almost completely unresponsive, including not responding to the drive commands issued from the iPad that we often use to manually move it around.

I checked the log, and among other things noticed that the time difference between the above mentioned entries was over 2 minutes!

Any idea how/where those wireless messages could sit for that long without being completely lost?

I seriously doubt the PLC would hang onto it, so that leaves our company network and the AMR.

Our IT dept. swears it couldn't be in the network (but they've been wrong before . . . . .)

 

In addition, I'm seeing that the robot periodically (at least once per day) is losing the wifi connection and not reconnecting - normally we see about 2 bars of signal strength. I'll try to connect and fail, then when I go to the robot it's showing zero bars.  Restart the robot and it's back to 2 bars.

 

I've contacted Omron technical help, but it took us a while to get a log file (too big to send via email) to them, now I'm waiting for a response - thought I'd ask the brain trust to see if anyone had ever seen something like this.

[photovoltaic]

How long ago did you purchase the robot?

[DonNH]

We got the robot a bit over a year ago - spent some time figuring it out & getting the other stations up & programmed, then deployed it on a limited basis at the beginning of this year.

Our initial application is moving some tooling around, where the robot doesn't actually provide much of a benefit -- if we can get the bugs worked out then we can apply it to areas where it would be more useful. That will require a fair amount of factory rearranging, so it won't happen until we can show that this is more reliable than we've seen so far.

Omron's tech people try to be helpful, but especially with the shakeup they had a few months ago, they are short on appropriate people.

There have been communications issues all along to some extent - up til now they've appeared to all be related to our network - antenna placement, network & firewall settings, etc.  

Generally we find a problem, IT says it must be the equipment's fault, then we prove that everything points to a network issue, then they fix it.

Here, I don't know what way to point. Trying to figure out what part of the system could actually hang onto a message for a couple minutes before moving it along.

[DonNH]

On 10/2/2024 at 2:27 PM, DonNH said:

 

 

On 10/2/2024 at 4:59 PM, photovoltaic said:

How long ago did you purchase the robot?

 

 

 

Update - 

 after long delays in responses from Omron (Sent them a link to an ftp site with the debug file, a week or more later they ask for the link again, then another week or so later they say the link doesn't work for them, then they send a link to their box site, which my firewall blocks , , , , , , , , ,)

Anyway, they finally looked at the debug file and came back saying the wifi card in the robot is bad.  Waiting for an RMA and instructions on pulling the core, which apparently we'll have to send to them to have repaired/replaced.

Edited November 15, 2024 by DonNH
clear out quotes from previous posts

[DonNH]

On 11/14/2024 at 8:37 AM, DonNH said:

Update - 

 after long delays in responses from Omron (Sent them a link to an ftp site with the debug file, a week or more later they ask for the link again, then another week or so later they say the link doesn't work for them, then they send a link to their box site, which my firewall blocks , , , , , , , , ,)

Anyway, they finally looked at the debug file and came back saying the wifi card in the robot is bad.  Waiting for an RMA and instructions on pulling the core, which apparently we'll have to send to them to have repaired/replaced.

Update 2 -

From the notes in the RMA portal, it appears that when they received the controller, it was tested and checked out OK. They replaced the wifi card anyway, as that had shown up as bad when the debug file was reviewed  (and I've seen some other references saying this is a known issue).

Got it back and reinstalled.

Now I'm still struggling with the connection - when I'm plugged into the maintenance port I can see all of our VLANs with 2 bars of signal strength. When I set the IP address back to what we had been using, I would see two bars on the robot's display, but now it's displaying zero bars on the robot display even though it's showing 2 bars when viewed in SetNetGo.

Potentially even more of a roadblock is that it boots up with a fault that won't go away -

When I first booted it up, one of the estops was pressed, so it came up with an estop fault. I reset the button, and it recognized that it was released, giving me the standard message:  "estop has been released, press the ON button".  However, there's also the message: " Faults: ESTOP Safety Fault (1 of 2)"  which doesn't go away. I can activate and release each of the estops and they are recognized, so I don't know if there is another input which will trigger that fault or somehow it's just not clearing a flag in the program. 

I've sent a email to the people who are supposed to be my technical contacts, but no response for a week, so I've now gone to the regular tech support email. That typically takes quite a while to get more than the automatic "we've received your request" response.

Edited January 30 by DonNH