8/9/2019 12:03 AM | |
Posts: 6 Rating: (0) |
Hello, Here are the details of my system as suggested by the new topic instructions. This machine has been my first experience with Siemens controllers so I'm pretty inexperienced.
- Simodrive 6SN1118-0NH00-0xAx 611U 2 axis Closed-loop speed control Sin/Cos 1Vpp, Firmware version 03.04.03 - Sinumerik 840DI
- NC 48.04.0216/07/02 12:50:43
-PCU50/333MHZ+MCI-Board -0.6.03.01_PCUxx
Troubleshooting/commissioning
Technician My company has a vertical lathe with the Siemens controls described above. We have replaced the old direct measurement incremental Sin/Cos 1Vpp linear scales with new incremental Sin/Cos 1Vpp linear scales on both the X and Z axes. The new linear scales appear to be scaled correctly and produce accurate readings and we are able to jog the machine without any contour or velocity errors. However, when trying to reference either X or Z axis we end up with a 20002 Alarm "Zero Mark Missing". Reading through the commissioning manual for our 840DI controller (Commissioning Manual, 05/2008, 6FC5397–4CP10–4BA0) I find in section 11.5.19 Axis Homing that there are (3) phases involved when referencing an axis with an incremental measuring system like we have. We seem to get through phase 1 without any problems, the axis travels from the starting position to the reference cam, stops when it reaches the reference cam and then travels back the other direction. We don't seem to be able to get past phase 2 however. It appears the axis travels greater than the maximum distance defined in MD34060 without detecting a zero mark which triggers Alarm 20002. The old encoders had a value of 0.2 inches for MD34060 which seemed rather large. Our linear encoders are specified to have reference marks every 20 um, so we have set the value of MD34060 to 0.00078740 inches because our machine is setup in inches. This did not help so we set it to twice that amount and still we get the 20002 alarm. We've also changed the search direction reversal machine data to a value 1, MD34050 which did not help. If someone has an idea on something else we could try it would be greatly appreciated. Thank you!! Also I attached a picture of some relevant MD values. |
8/9/2019 6:58 AM | |
Joined: 4/23/2010 Last visit: 12/31/2023 Posts: 8092 Rating: (877)
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Hello, Alarm 20002 = Zero mark of incremental encoder is not within defined section i.e. within value specified in MD 34060. In the attached data sheet distance between two refernce mark signals is not specified. I suggest you to increase MD34060[1] value from 0.00157480 to say 0.5 inch & check. HTH. |
8/9/2019 5:27 PM | |
Posts: 6 Rating: (0) |
Hi SteveA and PISCEAN 2010, Thank you, I did not catch the reference mark spacing is different than the grid spacing. Looking on Newall's website we have a SHG-VP incremental linear encoder and they are specifying reference markers ever 0.5". We increased the MD34060[1] value to 0.5 inches, but unfortunately still came up with Alarm 20002. We then increased to 0.75, 1, and 3 inches and could not get past Alarm 20002. I agree with both of your conclusions that the controller is not seeing a reference marker within the distance specified in MD34060[1]. Is there some kind of synchronization between the motor encoder and the direct measuring linear encoders so that it is important the values in 34060[0] and 34060[1] are matching? I'm curious why we aren't also getting any value in 34093[0] which should be the distance to the motor encoder reference marker. I'm also fairly convinced we are getting a reference marker signal, yesterday we swapped the reference wire pairs thinking we may have them inverted (pins 4 and 12 off the SCC200 Datasheet) and we couldn't jog the axes without getting velocity and contour errors, which tells me the controller is seeing the reference marker signal and is using it to control movement. Is there a way to jog an axis and observe a signal to verify the controller is seeing the reference markers? Could there be a setting in our 611U axis drives that we are missing? Thank you for your help so far, it's very much appreciated. |
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