PDP Reading Incorrectly over CAN

[canine505]

We are trying to use the PowerDistributionPanel Java class to read the current from the PDP. The Current readouts are much, much higher than they should be, but only on channels that seem to be incorrect at random. For example, the overall current for the board is usually around 30 amps, with channel 2 around 23 Amps. The temperature and voltage readouts seem correct. Any ideas?

[Jon Stratis]

You need to provide some more information. What values are present for all the channels at any given point in time? What is hooked up to each channel, and what is it doing? Do you have a meter to independently measure the current for a channel you believe is reporting incorrectly?. By itself, a single channel pulling 23 amps while the overall is at 30 amps could easily be done with a motor under load hooked up to that channel, and little activity on the other channels of the board.

[canine505]

The values change apparently randomly, and nothing is hooked up to the channels reading high. It should be drawing 0 amps, correct?

[Ether]

Originally Posted by canine505

We are trying to use the PowerDistributionPanel Java class to read the current from the PDP. The Current readouts are much, much higher than they should be, but only on channels that seem to be incorrect at random. For example, the overall current for the board is usually around 30 amps, with channel 2 around 23 Amps. The temperature and voltage readouts seem correct. Any ideas?

Which thread would you like the responses to be posted to?

This one:
http://www.chiefdelphi.com/forums/sh...d.php?t=133169

or this one?
http://www.chiefdelphi.com/forums/sh...d.php?t=133172

[canine505]

Originally Posted by Ether

Which thread would you like the responses to be posted to?

This one:
http://www.chiefdelphi.com/forums/sh...d.php?t=133169

or this one?
http://www.chiefdelphi.com/forums/sh...d.php?t=133172

This thread, thank you.

[ozrien]

Be sure to update PDP firmware.
Instructions for updating the firmware are here: http://www.chiefdelphi.com/forums/sh...ht=pdp+current

The ship firmware does not zero the currents, so they can wiggle by a couple amps.

[Jon Stratis]

Unfortunately, the PRO user manual doesn't state any expectations for reading channel current.

I would guess that, in this case, this current sensor is essentially floating, which means the value it returns is meaningless. Try putting a breaker in the channels that are reading incorrect and let us know if they are still incorrect. Then try hooking up a low-current device to the channels and see if they still read incorrect. It's just a guess, but I think putting a breaker in will be enough to stabilize the current sensor and give you the expected result.

[Jared]

Originally Posted by Jon Stratis

Then try hooking up a low-cost device to the channels and see if they still read incorrect. It's just a guess, but I think putting a breaker in will be enough to stabilize the current sensor and give you the expected result.

Be careful and don't plug a motor straight into the PDB, it'll fry the current sensor!

[Tom Line]

Originally Posted by Jared

Be careful and don't plug a motor straight into the PDB, it'll fry the current sensor!

Have you tried this already? It sure seems like the breaker should protect it against over-currenting the sensor, though I don't want to be the guinea pig to prove it.

[ozrien]

Do not connect a motor directly to the PDP...

Warning: Inductive loads (motor, compressor) must have a power management device (motor
controller, PCM, spike) between itself and the PDP. No inductive loads (motor, compressor)
may be directly connected to the PDP channels as this can damage current sense circuitry.

Bottom of section 2.2.1 and 2.2.2.
PDP User Manual
http://www.crosstheroadelectronics.c...ol_system.html