Last night I updated my PMU 24 DL to 101.2 (from 101.1). Since this, I’ve noticed that its not showing the correct current draw on output 2. I used to see around 0.8amps but now I’m seeing zero. The pump connected to this output is working as expected. I use this for am alarm to warn me if the waterpump is not drawing current.
This is data logged before the update:
Is the current measurement issue only visible on output O2? Have you tried performing a downgrade, and if so, what is the current measurement on O2? I tried to reproduce this issue on a test bench, and everything works as expected.
About downgrade firmware, simply perform “Upgrade firmware” to an earlier version, specifically to 101.1, and check if the current measurement returns to the correct values.
I have loaded your project, and it still works as expected on my test bench – current measurements are functioning correctly on 101.2.
Could you collect logs directly from the PMU instead of the EMU or DM
on 101.1, and then after the upgrade to 101.2, with logging enabled for channels related to outputs?
Have you tested the current measurements on other outputs? If not, could you check if this issue only affects O2 or if any other output shows the same behavior?
This is also 101.2, but I’ve also included in the same screenshot the current from my battery isolator. You can see where I toggle the power state of output 2. The isolator current increases by around ~6amps, but the PMU see’s an output change of around 0.04 amps:
Could you share the project and log file instead of screenshots?
How have you connected the water pump to the PMU? Could you provide the wiring diagram?
What type of water pump have you installed?
From the screenshots you shared, everything looks fine. In FW 101, there was an issue with incorrect current readings for very small currents, which is why you see the same readings for 92 and 101.2(where mentioned bug is not exists).
It seems like your pump is not powered directly by the PMU. Instead, the PMU might be acting as a switch, powering a relay or something similar.
Please provide the details requested in points 1, 2, and 3 for further troubleshooting.
The controller sends a signal to the internal pump electronics but does not directly power the water pump—it only controls it.
Therefore, the current measurement displayed by the PMU is fairly accurate. If you want to measure the current drawn by the water pump, you need to power the pump directly from the PMU.
Here is a diagram taken from the tinyCWA manual (if you have the CWA100 with a 3-pin connector, please use the appropriate diagram). Could you modify this image (in Paint or any similar tool) to show us precisely how your pump, controller, and PMU are connected? Once we have this information, we can proceed with resolving your issue.
In that case, the current measurement should reflect the changes detected by the battery isolator, as you mentioned.
For testing purposes, could you run the pump at maximum speed and check the current measurements for O2 in the PMU client?
Is it possible to connect another load to the O2 output to verify if it measures anything? For example, a 12V car bulb?
Do you have the option to temporarily use a different output for the water pump to test if the incorrect current readings occur only for O2?
I noticed in your project that O1 is used for the water pump PWM. Are you using this output even though you are using an external tinyCWA controller?
Yes I will do some test with pump running at full speed, I can also add another load to o2 to test. o1 is not being used so I can use this output and with the pump and controller and compare the results
