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Intermittent overload COUT error

SJ L 4 weeks ago in Master modules / MC4x updated 2 weeks ago 4

Hi, I have an issue with intermittent MC43 COUT overload errors on one of our machines.

Status is OK and operates well in most conditions, but will randomly report overload (even when that function is not requested).

I have tested the solenoids, plugs, and wiring harnesses within this circuit and all looks ok.

COUT circuit C1:16, 41, 57.

Is there anything else I should check to see what might be going wrong?

For MC43 COUT-C (C1:16, 41, 57), also check the adjacent MC43 COUT-D (C1:30, 42, 58)

When an overload is detected on either of the two COUTs, the shared supply to the two adjacent channels is cut, and both get the status overload. 

Another point to check is the COUT min current. If you try to control a current too far below the specified 100 mA, the regulator could have problems. This will also affect both channels, even if one is inactive. 

Thank you for that, I wasn't aware the two COUTs shared supply. 

From that, I terminated the connections on the COUT-D circuit - they were previously optional outputs that were not being used on this machine. 

However, the issue still remains where COUT-C is getting the overload error, intermittently. 

The minimum requested current for the channel is 350mA.

Are there any other checks I could complete?

The next thing to check could be the load; if you have a large load (low resistance), the problem could be that the peak current could becomes too high. 

For example, if powering a 12 V coil in a 24 V system. 

See Maximum load in the MC4x Appendix A info: 

Image 3397

If this is the case, setting a higher dither frequency on the COUT could help. 

You find the COUT PWM frequency on the MC4x module pin properties in IQANdesign. 

Hi, I increased the PWM frequency but this still hasn't addressed the issue. 

The OVERLOAD error shows, intermittently, even when no output has been request for that COUT function. 

I am working on some logic to mask this as best I can but still need to find the root cause.