MC050-018 C1P23 INCORRECT VOLTAGE

[Mike AA]

So I have an input port, C1P23 acting up on an MC050-018, I ran out of MC050-118 or I would be using it but doubt that's the issue, and needed something right away when I started the project.

I have this input connected to a mag flow meter with an open collector signal (grounds out when it sensed a gallon of water so  it flips a lot at 400-600GPM).

The settings
pinconfig0=1
Pinconfig1=0

I had it hooked up fine no issues for about 3 days. Around 20000 gallons per day.

Suddenly FRIDAY the signal petered off to 0 GPM While flow still going. Checked all the wiring and double checked when I was changing code I didn't do anything with flow meter.

0 freq
0 count

Strangely without anything hooked up the voltage was about 2300mv should be 5000 since pinconfig0=1 means pull high to +5.

I changed pinconfig1= 3 and got my flow working again.

What is going on with this input? Did my internal resistor go bad?

I have another flow meter hooked to C1P25 with no issues, same settings as I initially had for C1P23 and it has done close to 200000 gallons.

Thoughts?

Thanks,
Mike

[oiltronic]

At 600GPM it's only flips at 10 Hz, which is nothing.

Does the voltage measure 2300mV via multimeter or service tool?  That voltage implies pinconfig=3 with both pull-up and pull-down resistors enabled, so if you had pinconfig=1 it implies the pull-down is also active.

I don't understand how enabling both pull-up and pull-down would make it work (pinconfig=3), because then I would expect 2500mV with nothing connected, and it would never trigger the default high threshold (DigThresHigh) of 3000mV.

I once has a whisker short inside that blasted non-serviceable 50-pin Deutsch connector that caused similar problems.  So what if you removed the connector, connected only power & CAN on pins 1-4 and then checked the pin voltage when the pin config/bias is 1?

Another thought is whether the ground on the meter is the same as the MC050, which can be checked with a multimeter.  I would just measure between the signal from the mag flow meter and the ground at the MC050.

[Mike AA]

OILTRONIC,


At 600GPM it's only flips at 10 Hz, which is nothing.
I realized this after posting its nothing compared to my motor speed sensors which will run in the KHz.

Does the voltage measure 2300mV via multimeter or service tool?  That voltage implies pinconfig=3 with both pull-up and pull-down resistors enabled, so if you had pinconfig=1 it implies the pull-down is also active.
Voltage measures both service tool and multimeter at around 2300mv. pinconfig0=1 for pull up because my flow meter is open collector.

I don't understand how enabling both pull-up and pull-down would make it work (pinconfig=3), because then I would expect 2500mV with nothing connected, and it would never trigger the default high threshold (DigThresHigh) of 3000mV. Pinconfig1=3 not pinconfig0=3

I once has a whisker short inside that blasted non-serviceable 50-pin Deutsch connector that caused similar problems.  So what if you removed the connector, connected only power & CAN on pins 1-4 and then checked the pin voltage when the pin config/bias is 1?
Unfortunately I Am not around this equpment for about 2 weeks. I can double check this when I return to it

Another thought is whether the ground on the meter is the same as the MC050, which can be checked with a multimeter.  I would just measure between the signal from the mag flow meter and the ground at the MC050.
The magflow meter comes directly from the box which the controller is installed in for ground and power.

I still don't understand why its 2300mv

[ToddT]

Setting PinConfig1=3 (Range is maximum of approx. 2.465v). The maximum voltage is capped at approx. 2.465v.

PinConfig0 = 1 (Pull up resistor), when open, the voltage at the pin will be +5v, but the setting of PinCong1=3 limits the voltage to less than +5v. Set PinConfig1=0 or 2 and then check the voltage at the pin, it should be +5vdc when open.

[acmall]

I still don't understand why its 2300mv

Sounds like something is wrong if you are measuring 2300mv on C1P23 with nothing connected and PinConfig0 = 1.

Did you try measuring it with PinConfig0 = 2 to see if it pulls down to ground? I am wondering if it is possible that the circuitry that switches the various resistors in and out has failed.

[Mike AA]

acmall,

This is what I am somewhat wondering, if internally it has failed. I plan to check if changing pinconfig0=2 does bring it to zero, but I won't know for about 2 weeks yet.

  I really hope it's something I missed or something to do with the older controller. If it is indeed an issue with the controller then it will be the first failure of about 40ish components that I have installed.

Mike