Troubleshooting Speed Discrepancy with PowerFlex 753 and Analog Input 4-20mA

Question:

I am currently using a PowerFlex 753 connected through analog 4-20mA. However, there seems to be a discrepancy between the speed reference I input from the HMI and the actual speed output. I am utilizing Automation Direct productivity hardware for this setup. To calibrate the system, I adjust the HMI command from 0-100 to the required analog card range of 0-65535, with an output range of 4-20. A Fluke clamp-on 4-20mA meter confirms the correct current output for a specific speed, such as 12mA for a 50% command. Upon checking the PLC and the drive, Parameter 522 is set to zero and Parameter 520 is set to 60. Despite this, when I command 100%, I receive only 59.9%, resulting in a speed of 35Hz instead of 50Hz. It appears there may be a parameter issue within the drive configuration, possibly stemming from the previous intervention of an inexperienced electrician. Since I am currently without the necessary serial port connection, I am unable to fully investigate the issue. Although the blame has been wrongly placed on the PLC, I suspect the root cause lies within the drive settings. Any insights or advice on resolving this technical issue would be greatly appreciated.

Top Replies

What do P261 (Analog In 0 Hi) and P262 (Analog In 0 Lo) settings signify?

I discovered the addon IO card that had been tampered with by the general manager, resulting in the ma min being set to 0.

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Frequently Asked Questions (FAQ)

FAQ: 1. Why is there a speed discrepancy between the input reference and the actual output speed in my PowerFlex 753 setup?

Answer: - The speed reference discrepancy could be related to the configuration settings within the drive, especially if Parameter 522 and Parameter 520 are not set correctly. It is essential to ensure the drive settings align with the required speed ranges.

FAQ: 2. How can I calibrate the system when using an analog 4-20mA input with a PowerFlex 753 drive?

Answer: - To calibrate the system, you need to adjust the HMI command range to match the analog card range, typically from 0-65535, with an output range of 4-20mA. Using a current meter can help confirm the correct current output for specific speed commands.

FAQ: 3. What could be causing the issue of receiving only 59.9% speed output when commanding 100% in my PowerFlex 753 setup?

Answer: - The discrepancy in speed output could be due to incorrect parameter settings in the drive configuration. It is crucial to review and adjust parameters like Parameter 522 and Parameter 520 to ensure accurate speed control.

FAQ: 4. How can I troubleshoot the speed discrepancy issue in my PowerFlex 753 setup without a serial port connection?

Answer: - If you lack a serial port connection for detailed investigation, you may need to focus on checking and adjusting the drive settings accessible through the HMI or any available diagnostic tools.

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