I have a group of students stuck on Lab 3- Manual Movements. When they run the manual movements code the coordinates displayed on their brain don’t match the way the coordinate system is explained in the lab. See pictures attached. The coordinates also drastically changing every time we download the code. For some reason their y-coordinates keep coming up as negative when they should be in the positive. We have remastered this thing several times and redownloaded the code. What’s the problem? Is it one of the potentiometers…if so how do I tell which one? Is it the brain? It’s updated. It’s not the software as we have tried several laptop/computer.
Hi @rcross, are you using a V1 Potentiometer for Joint 1? Identifiable by their red color and circular shape, shown below.
These V1 potentiometers may provide inaccurate values, which the arm uses to calculate these coordinates. Would you be able to swap it out for a V2 Potentiometer, shown below?
Also, check out Frequently Asked Questions of the V5 Workcell as it walks you through troubleshooting steps to determine if you have a troublesome potentiometer or not. Do you have multiple Workcells? And are you experiencing any of the same problems with them? Let me know, and sharing images / videos will be the easiest and quickest way to streamline your issue and get your Arm back on track!
1 Like
We actually started with the V2 potentiometers on all the motors and was having the exact same problem with the quadrants and readings. One of the students thought maybe it was the potentiometer on joint 1 so we switched it out. The workcell didn’t come with extra v2 potentiometers so they just put a v1 on just to see if that would fix the problem. It didn’t. The quadrant readings were similar with v2 potentiometers so that makes me think it’s not a potentiometer problem. I have 9 other workcells that seems to be working fine. This is the only one where the quadrant readings just seem completely way off. It seems to mainly be the y-coordinate that is completely off. I’m not sure what else it could be.
The Y coordinates are interpolated through Joint 1 readings, so if there is an issue with the hardware, the Y values will be off as you are seeing. I want you to test the V2 Potentiometer you removed from your Workcell. Plug the Potentiometer directly into the V5 Brain, and view the dashboard readings from it. Manipulating the potentiometer’s wiper blade similar to the image below, can you see these values change according to input movement?
If you see these values changing with movement of the inserted axle, the potentiometer should be operating normally, so please install it back onto the Arm and give it another Master. If no values change with the associated potentiometer, we’ll progress further as this may be faulty hardware.
1 Like
I’m actually having this problem with two workcells (out of the 10 I have). It seems to be the y-coordinate. Here is some images from another workcell. It has a v2 potentiometer on all motors and I checked each one to make sure it was working. I know the rubber bands are incorrect, but that shouldn’t be influencing the coordinate readings. As you can see we also tried using a new V5 brain to see if that is the problem. We also replaced all the 3 wire extenders on all the potentiometers as well and double-checked those connections.
We have yet to most past lab 3 manual movements on these work cells.
This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.