Not reproducible

XC44 HS+LS Overcurrent

CalebD 2 years ago in Expansion modules / XC4x updated by Gustav Widén (System support) 2 years ago 10

We are experiencing a problem with the HS+LS outputs on an XC44 module connected to an MC43 as the master running IQAN 6.07. Pin C1:46 as the HS and pin C1:41 as the LS.

The outputs are being used to activate a solenoid. The circuit was wired to run through a relay latched by system estop, with a diode placed across the solenoid to protect the outputs as in the documentation.

Image 2927

This circuit is able to latch and unlatch the solenoid with no problems, and this was repeatable many times. However when the system estop is pressed for the first time and the relay unlatches and breaks the circuit there is no error. When the relay is energized and the circuit is connected again, when the output is turned on a message is displayed reporting that the LS pin is overloaded. This message then triggers on either side of the estop from that point on. Key cycle is able to "reset" to the first estop cycle. This behavior happened ~9/10 times the cycle was repeated. There were some occasions where the error did not trigger.

The overcurrent error will only trigger when the output is requested, the estop relay can be re-energized connecting the circuit and no overcurrent is reported. 

Current measurements were taken on the HS+LS wire to investigate. The current on this wire never approaches or exceeds the listed 2.5A. This is the only load on that pin grouping, the other 3 LS pins were not used.


Image 2928

I'm experiencing the same problems, on a XC44 

DOUT (C2:47 & C2:67 is connected too a hydraulic valve with a 24v/1.3A coil and clamping diode. When switched on a overload accurse

Running 6.06, On MD4-7, XC43, XC44


The case you describe sounds different, C2:47 & C2:67 are Digital out HS. For a Digital out HS that report an overload when activating, the first thing I would check is if the diode is fitted the right way. 

Under review

There are multiple diagnostic tests that get reported as status overload on the DOUT HS+LS, both for the case when the DOUT is on in the application, and when it is off. 


Where does the relay cut the circuit? Between HS pin and coil? 

As you write there is no error reported when the circuit breaks, it seems as if you have DOUT undercurrent detect set to No in IQANdesign and keep the DOUT on in the application? Otherwise there would have been an open load reported when cutting the load externally. 

On the other hand, it seems from the description as if the overload is only reported when re-activating the DOUT? So I think it should have reported open load at some point. 

This might be an unrelated wiring issue, but I have a machine that has started reporting overload on all the COUT with loads connected since 6.07.

It is an MC43FS and it happens about one in five times the machine is started, mostly I think it is after a longer shutoff maybe when all capacitors in the module has discharged.

The machine is powered by an isolated converter from 96V->24V.


For the machine where you see overload, what type of loads do you have on the COUTs? 

It is mostly Parker P70 and L90 valves. It happens to all the COUTs on the module and only at power up when all outputs are off.

I am still getting overload on boot even though the outputs are not active. Is it possible that a voltage drop or voltage spike could cause it?

There are three big 24V contactors activated by inverters approximately 300-500ms from boot.

It also happens with 6.06, and we tried replacing with a different MC43FS.

1 or more (upto all) COUT get overload on boot, but only if the machine has been shutoff for more than a few minutes.


Right now I have the feeling that the COUT overload you are seeing is different from the DOUT HS+LS issue Caleb saw, but I do not know. I will contact you separately for more in-depth troubleshooting.

Not reproducible

The continued discussion on original post ended up here: XC44 HS+LS Overcurrent Update / Hardware / IQAN