Under review

XC44 HS+LS Overcurrent Update

CalebD 10 months ago in Expansion modules / XC4x updated by Gustav Widén (System support) 10 months ago 1

I am still unable to reply to previous posts with the same error being reported as before when I attempt.. 

In reply to Gustav's comment on this post: XC44 HS+LS Overcurrent Follow Up / Hardware / IQAN

"Ok, the disabling of the function group explain at least a part of the behavior you see.

When disabling the FG, the DOUT deactivate. Diagnostics is still running, so when disabled all checks for output off are running. In IQANdesign you will only see channel status disabled though.

At what events do you disable? Only before cutting the highside externaly?

Or also during normal deactivation of the output?"

The function group is only disabled on Estop. Before an estop event the output functioned as normal, the estop being triggered starts the overcurrent issue. 

Original post: XC44 HS+LS Overcurrent / Hardware / IQAN

Under review

This was a tricky one.. I would rather recommend switching off the module completely or using an FS module for the stop function. But I'd like to understand what is going on here. 

So the stop command is read by the IQAN module and this disables the FG. This switches off the DOUT. 

Since the DOUT is then off, it is the diagnostic methods for an output that is off that are now checking the circuit. 

At more or less the same time, a relay cuts the connection between the DOUT and the valve coil, so it is switched off also externally. This triggers the open load detection, but due to the output being disabled, the error is suppressed. 

In the original post, there was a scope measurement that showed the current was declining to zero over roughly 80 ms. From that I conclude it was the current through the coil that was measured, right? 

When the DOUT is switched off, one of the diagnostic checks measure current to see that there is no current out from the HS. This "off check" is one of the different methods that give DOUT status overload if it fails. 

Assuming the diode is a regular diode, I would expect the current out from the module to drop to zero in less than a ms when the output it switched off. 

Is the diode a regular diode? 

Is it possible to repeat the current measurement and measure current out from the HS?