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Disable open load DOUT MC42

Robin arvidsson 1 year ago in IQANdesign • updated by Gustav Widén (System support) 1 year ago 4

i'm sure i've seen it somewhere, that it would be possible to disable open load detection on a DOUT. 


But i can't seem to find it..


Is there a way to disable open load detection on MC42 DOUT ?

Answer

+1
Answer

In 5.02 - go to the output on the module in the system display and click on the output.  The property is on the right side now.

+1
Answer

In 5.02 - go to the output on the module in the system display and click on the output.  The property is on the right side now.

That's under current detection, This does not disable "Open load" error, in my application at least.


i've set this to "No" already..

By disabling DOUT under current detection, you are disabling the ability to detect open circuit when the DOUT is ON, but you still have the feature for open load detection when the output is OFF.

On the MC4x series, the Digital out HS have two ways of detecting open circuit of the load, both methods result in the same channel status, Open load

  • When the DOUT is ON, the DOUT detects open load by using under current detection, checking that the current is >60 mA. If current is below, the DOUT status is reported as open load. This is the test that can be disabled with the property DOUT under current detection on the pin. 
  • When the DOUT is OFF, the DOUT detects open load by measuring voltage on the pin. The relatively high leakage current in OFF state (up to 2 mA) is there to make it possible to measure this. When the load is properly connected it pulls the voltage to ground resulting in a voltage measurement close to zero, and the DOUT status will be OK. If there is an open circuit, the voltage on the pin will be close to battery voltage, resulting in an DOUT channel status open load. 


If you want to disable open load detection for an output altogether, you can place the DOUT in a function group, and disable the function group. This is the method I would recommend for outputs that are optional.


MC4x instruction book Appendix A