I purchased a few of the PR55-4A current monitors. Most of them work as expected, reporting a reasonable number of amps without adjusting the calibration (60.6). One unit however, consistently reports very high values (reaching past 15000), while another (working) sensor on the same line reports near 8A consistently.
I tried swapping the current clamp with the working unit, and even the internal cable. Neither helped the issue.
Finally I tried reducing the calibration down to a negligible value 0.035), but the reported values now range between 1850 and 1855. It seems there is not just a calibration issue but an offset.
I did notice that inside the enclosure of the faulty unit, the unused input connector has been removed. Is this a faulty unit, or is there something we can do to recover it?
I retrieved the sensor and opened the lid. The connector was not seated as poorly as in this photo (photo was taken at an earlier date during testing).
I unplugged the identified cable and reseated the connectors at both ends. No change in measurements.
In the plot attached you can see measurements in application. Starting on the left (while clamped to line with ~8A draw), then you can see where I disconnected the current clamp, and then where I disconnected the internal cable briefly. Finally you can see a drop when I plugged the current clamp back in.
Calibration is still at .035. The values reported at the beginning and end are about 1855.
Not really no. it is reporting a value of 1855, but that is not calibrated to any particular unit.
I have at least 3 more of these around the shop and they work as expected.
With a default calibration of 60.6 on a 120v line drawing 8A, I see a value of 8.something.
With this particular unit, when the calibration is set to the same default value of 60.6, I see values in the thousands. I’ll attach some graphs measuring the same line over the same time range for comparison.
The Node Red version is 3.0.2
Or are you asking about the NCD pallet? (0.1.13)
Sensor Firmware version is 2 (all Current Monitor devices)
First try i performed the factory reset with the current clamp disconnected. After that, with clamp and load connected, every read brought in a value of 0A regardless of load.
Then I did a factory reset again, this time with the current clamp connected but not attached to any load. Now when connected to my line with 8A, I am seeing values around 10.something Amps, and 0 when I turn off the load. The readings are much more reasonable and consistent now so I’m confident that I can use the calibration factor to fine tune the current measurement the rest of the way.
I think this issue is resolved.
Next I’ll have to figure out why current change isn’t working on this device.
