XC23 Can Error Flash Disabling Module?

Kevin 6 years ago in Expansion modules updated by Ulrik Zakariasson (Software development) 6 years ago 8

We have a system with MD4 connected by master bus to MC3. We have a XC23 connected to the MC3 via expansion on different bus to master.

On ignition switch on the system appears fine and all outputs and inputs into XC23 are OK, during engine start there appears to be a dip in voltage which causes the XC23 module to show 3 red, 1 amber LED flash (can error / timeout). When we get this error flash, IQAN run says system health is OK under the XC23 and MC3 modules and IQAN design shows the outputs on XC23 going true and false as expected. XC23 module outputs however are non functional, the module is in error state and refusing to operate outputs whilst the LED flash sequence above is active.

There are no logs in the MC3 for failed communication with XC23.

Are there any recommendations for how to resolve this? Is this normal behaviour for a dip in voltage on XC23? All other modules appear to be unaffected by voltage dip, its almost as if XC23 does not recover and outputs are non functional even though IQAN design thinks they are? Would pulsing 'enable' property just after engine start re-enable the module in event of this error flash?

Running IQAN Design 4.07 with machine voltage 24V dipping to around 10/12V on startup.

Version of IQAN 4 is 4.07.14.

The module appears to still be 'alive' with this error state present because as soon as I power the module down I get errors on MD4 stating voltage inputs are low, as expected. This however does not explain why the outputs are non functional?

Does anyone have any suggestions as to what may be the issue?

Under review

It doesn't really seem to match the symptoms you are describing, but it is worth checking to make sure it is not the interlock for reactivation of DOUT:s, this has been quite confusing to some. 

If you loose and then regain contact with an expansion module any outputs that are on will remain in the error status No contact, until the channels controlling the outputs have been false or zero. 

The block diagram would look something like this when you measure on it: 

In this situation, the LED on the master module will keep blinking the 3:1 indicating No contact, but the expansion will have resumed its normal OK blink. 

But from your description, it seems as if the XC23 is the module that keeps showing the 3:1 blink? 

Have you confirmed that the MC3 has recovered and is running? You wrote that you saw some channel values changing in IQANdesign, so I assume you were connected and measured channels on the MC3?

A more general question, what is the firmware version of the XC23?

When faulting the MC3 is always showing OK error flash on the module. Its only the XC23 that shows the error fault 3:1 just after start-up.

The XC23 module has been set to 'yes' in the enabled property in the module list for the XC23. With this property we get the following scenarios


Ignition on > MC3 OK - Blink LED on MC3 OK, MC3 module is responsive on inputs and outputs.

                     XC23 OK - Blink LED on XC23 OK, XC23 module is responsive on inputs and outputs

After engine start-up > MC3 OK - Blink LED on MC3 OK, MC3 module is responsive on inputs and outputs.

                                    XC23 Not OK - Blink LED on XC23 showing 3:1, XC23 hardware is not responsive on inputs or outputs, even after cycling outputs from true to false. No indication of communication fault on MD4 display, measuring the inputs and outputs on XC23 using IQAN design all seems normal, outputs on XC23 module when viewed in IQAN Design appear to switch true and false as expected, just the module is not switching outputs. Voltage inputs have frozen to their last value before the module faulted during engine start-up. I never get the red no contact as shown in your image above, they are green and healthy, its almost as if IQAN Design does not know the module is not responding, and thinks its OK, below is an image taken when the module has faulted (the status under diagnostic is the only thing which appears to know something isn't right).

In the latter scenario, if I disconnect the XC23 connector grey (6 pin) and reconnect, the module recovers, outputs and inputs start responding again.

I then inserted a IDC that switches the module enable property for XC23 Off when the battery voltage dips below 20V when measured from the MC3 that's using the XC23 as an expansion module. During all start-up's we now get a fully functional XC23 every time, after every start-up we get healthy LED flash on MC3 and XC23, all inputs and outputs are responsive on both modules.

MC3 running Bois 1.03, software

XC23 running Bios 1.00, software 1.02

Thank you for the very detailed explanation Kevin; I still cannot understand what it is that is going wrong but the information you provided is very useful. 

The  XC23 firmware version 1.02 on your module is the version that was used up until quite recently (modules built after 2017 week 32 have version 1.04), that I am unsure of whether this could have anything to do with the strange symptoms.

When you were cranking the engine, did you see the MC3 restarting or not? Should be possible to see in the systems log. In a 24 V system I'd expect both the MC3 and XC21 to stay on during cranking, but it is perhaps possible that there could be problems on the CAN bus. 

Can I ask one more thing of you? Is it possible to get a CAN trace with IQANanalyze of the expansion bus when this situation occurs? 


I have taken samples of the CAN expansion bus three times, twice (data set 1 and 2) with the module 'enable' property set to 'yes' so the module faults and the third time ( data set 3) with the 'enable' property set to only activate when the battery voltage is above 20V (the module did not fault this time). I can confirm all three engine cranks the MC3 did not restart according to the log files.

One thing I haven't mentioned yet is the expansion bus also has an XC10 module as well as the XC23, the XC10 functions fine every time and we do not get any issues with this module (LED always flashes normal functioning module). You may see some extra data on the bus because of this module.

I will send the files across Gustav.


Thank you Kevin! I have looked at the IQANanalyze files, and figured out a way to reproduce this problem. 

What seems to be happening is that the voltage drops very briefly, causing the XC23/22/21 to restart, but the expansion comes back online before there is a No contact. 

When I tried different combinations here on the bench, I am only able to reproduce the problem with cycle times of 50 ms and higher, for shorter cycle times the master module is detecting a No contact and deals with it.


This has been fixed in IQANdesign 5.03 (case 47187).