DO module: Detecting open load

[aharrah]

The page describing the I/O modules mentions:

Each output can additionally be configured to detect open load conditions when in high side switch mode and send an alarm to RevPi Core.

How do I read or get notified of the alarm when there is an open load condition?

Thanks,
Andy

[dirk]

Hi aharrah,
you have to read out the variable "OutputOpenLoadDetect", i.e. by "piTest -r <variable>".
Have a look at this tutorial How to Configure Digital I/O Modules

[aharrah]

That page had some good information on it.

After configuring OutputOpenLoadDetection how do I check to see if there is an open load on an output?

In digging a little bit I did come across this page: https://revolution.kunbus.com/tutorials ... iguration/ which includes the following:

OutputOpenLoadDetection has not yet been put into practice.

Is this a still a true statement?

Thanks,
Andy

[dirk]

Hi Andy, we have updated our documentation. The feature is working and the description how is available here:
https://revolution.kunbus.com/tutorials ... iguration/

[cerberus78]

Can you please show step by step for this point ?

i didn't manage to get the status. The status is always 0... when is should get some data

[cerberus78]

i have configured OutputOpenLoadDetect with value 255 so that i have the status of the 8 first outputs
but how to read the status ?

Regards

[dirk]

Hi cerberus78, it is the variable "Output_Status" which indicates a broken cable for the activated channels.

Code: Select all

piTest -r Output_Status

Here is a practical example in case you want to monitor a broken cable on output 1 using a 24V LED:

• Connect a 24V led on output 1 and switch on via "piTest -w O_1,1"

  

  DIO LED Output 1

• Configure open load detection for output channel 1:

  

  Don't forget to do the two steps in the PiCtory menu afterward: "File → Save as standard configuration" and "Tools → Reset driver"
• Continuously read the status of the outputs

  Code: Select all

  piTest -r Output_Status
  2 Byte-Value of Output_Status: 0 dez (=0000 hex)
  2 Byte-Value of Output_Status: 0 dez (=0000 hex)
  ...
  

• Then switch off the LED connection - here I just did it by removing the GND connection:

  

  DIO LED Switch of

• Continuously read the status - it changed to 1 which indicates the open load detection on channel 1

  Code: Select all

  piTest -r Output_Status
  2 Byte-Value of Output_Status: 1 dez (=0001 hex)
  2 Byte-Value of Output_Status: 1 dez (=0001 hex)
  2 Byte-Value of Output_Status: 1 dez (=0001 hex)
  ...
  

[cerberus78]

Thank you !!

[cerberus78]

after testing it is not as expected

what i wanted to do is to detect if an output is disconnected or not
the ouput can state can be on or off.

with the configuration you showed me we consider that output is always on

is there a way to do this case ?

[dirk]

No, unfortunately. You need to have a load to detect an open load and thus some electricity flowing through a cable.