Having trouble with DeviceNet on my 1756-L55 setup, where a PF700 recently malfunctioned. I am now trying to commission a new PF753 with a 20-Comm-D module to replace it. Additionally, a 2262D-2R is installed for a remote Auto-Off-Hand selector switch. Despite setting up parameters for the Hand function and remapping Inputs and Outputs for the PF753, the commanded speed remains at "0.00". The controller is sending a reference of 3300, but it's not translating to 33 Hz as expected. P545 is configured for Port 4 Reference, while P874 shows 0.00 for Port 4 Reference. Despite extensive manual review, I'm unable to pinpoint the issue. Why is the speed reference not reaching the drive effectively?
The PowerFlex 700 series utilizes a range of 0 to 32767 for adjusting speed from minimum to maximum. What value does parameter 2 show when sending the speed reference to the Variable Speed Drive (VSD)?
It's been a while since I worked on this type of interface, but it appears that DPI Port 4 is indeed the correct option module slot on the PowerFlex 753. The drive is receiving start/stop commands from the network without any issues, ruling out any problems with the DeviceNet network protocol or connectivity. Parameter 545, known as Speed Reference A Select, determines the speed reference for the drive in Auto mode. You can choose between Speed Reference A or B using discrete inputs or network command bits. To set DeviceNet as the speed reference, Parameter 545 should be set to "874", corresponding to the Port 4 network module reference value. Parameter 930 should indicate the parameter actually being used for the Speed Reference, which should display a value of 874. The PowerFlex 750 series has moved away from the traditional method where 0-32767 represented Min Hz to Max Hz, a system used by A-B drives dating back to the days of the 1336 Classic on RIO. After researching in the Knowledgebase and user manuals to confirm my understanding, it became clear that for those using a 20-COMM-D, the speed reference units are integer numbers in 1/100 Hz, with a value of "3300" translating to 33.00 Hertz. However, when utilizing a 750-COMM-D option module, the value is a REAL. To copy a REAL tag with a value of 33.00 into the DINT element of the DeviceNet scanner linked to the Reference for the drive, COP (not MOV) must be used.
I mistakenly had the 20-750-Dnet module installed, but I knew it was the correct one. It had to be a genuine module to resolve my issue. Special thanks to Ken for helping me solve the problem.
From what you've described, it sounds like there might be an issue with the communications data path from your controller to the PF753 drive. While it's hard to pinpoint without checking your exact setup, it seems like the command value being transmitted isn't getting interpreted correctly by the 20-Comm-D module or the drive. One potential cause could be an error during the remapping process. It might be worth double-checking your I/O mapping settings in your controller to ensure they match the drive's expected input format. Also, verify if P545 and P874 are correctly set for your speed reference value. Sometimes, simply re-initializing these parameters can solve such issues. Just some areas to explore.
It sounds like you've done a thorough job troubleshooting the issue. Considering that you have already checked the parameters and remapped the inputs/outputs without success, I suspect the problem might be with the 20-Comm-D module. Sometimes the speed reference fails to reach the drive if the communication module isn't functioning properly. It's also possible that there could be an issue with the DeviceNet's configuration. Lastly, make sure the P874 is configured correctly - it should reflect the speed reference being sent. I'd recommend checking these first. Do also make sure the cables at both ends of the DeviceNet are connected securely. Even a tiny loose connection can disrupt the overall operation.
It sounds like a complex issue, but I'd first suggest checking if you have the correct assembly instance numbers and sizes in your I/O configuration for the PF753. This tripped me up in the past with DeviceNet and Allen-Bradley PLCs. If your configurations aren't aligning with what the 20-Comm-D expects, it could cause the drive to not receive the speed reference correctly. Also, it could be beneficial to verify P851 "Speed Ref 1 Select" and P852 "Speed Ref 2 Select" - these parameters should point to your desired reference source (like DN/NetRef). Lastly, do a double-check on your programming that sends the reference (the 3300) to the drive to ensure it’s addressing the correct location.
It sounds like you're deep in the weeds with that setup! One thing worth double-checking is the communication settings between the 20-Comm-D module and the PF753. Make sure that the I/O mapping on the module aligns perfectly with what the drive expects. If you're getting a reference back of 3300 but it's not translating correctly, there could be an issue with how the scaling is set up, or possibly a configuration mismatch in the drive parameters. Also, have you verified that the drive is actually in a mode that accepts external references? Sometimes it's a simple parameter that can cause the entire thing to get out of sync. This can be a real puzzle, but I hope some of those angles help you troubleshoot!
It sounds like you're dealing with a pretty tricky situation! Have you double-checked the DeviceNet configuration for the PF753 to make sure it's correctly set up to receive the reference from your controller? Sometimes, missing a small setting or mismatch in the mapping can lead to the speed reference not being translated properly. Also, verify that the baud rate and network parameters match between the devices, as a discrepancy there can often cause communication issues. If everything seems correct on that end, consider looking at the diagnostic codes on the PF753; they might provide useful insight into any underlying issues. Good luck!
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Answer: Answer: The issue could be related to incorrect parameter settings, communication configuration, or wiring issues between the controller and the drive.
Answer: Answer: You can start by verifying the parameter settings for the Hand function, checking the mapping of Inputs and Outputs, ensuring the correct configuration for Port 4 Reference, and confirming the communication setup between the controller and the drive.
Answer: Answer: Possible reasons for this could include incorrect parameter configurations, communication faults, wiring problems, or compatibility issues between the devices.
Answer: Answer: You may need to review and adjust the parameter settings, check for any communication errors, inspect the wiring connections, and ensure proper mapping of Inputs and Outputs to troubleshoot and resolve the speed command issue.
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