Problem with DO810, the chanel 4 is always on!
I have a problem with the Digital Output (model DO810), the chanel 4 state is always on, even if i set false in this output.
Could anyone help me indentify what's happening with this DO?
Voted best answer
Difficult to say from the picture, you can check the following:
- You have to check hardware connection and variable, connected to this output (on-line)
- The LED will lit ON in case for some reason 24VDC is applied to the module from outside (TU's terminals)
- Profibus is not working correctly (DO810 is disconnected) and you don't use OSP value=false (in HW configuration for the module). Simple test - connect PulseGen output (1 sec pulse, 2 sec period from test application) consequently to Channel 3, then to channel 4. Check if the outputs are blinking
- The channel is broken (output transistor is blown and always open)
If its static LED then Check the Output is not inverted on the channel level on process demand or check for the logic if any.
if its lab system then link some other variables than your logic then try download and check.
If its Chattering like 1 and 0 like that then make the setting in the hardware settings of PM866 node as "None" for copy unconnected signals this recomended for the live/production system.
Check few things...
1. check if Channel is not forced ?
2. check if this channel is written from multiple places ?
3. check logic, variable connected to this hw channel might be inverted ?
4. Check physical wiring if by mistake any souce connected to this hw channel instead of input ?
Hope that helps...
1. Remove the wiring corresponds to the 4th Channel, if it resolves then problem is on external wirings might be connected to any source
2. Even by removing the wiring corresponds to 4th channel doesn't help, then disconnect the variable connected to this 4th channel in CBM HW tree, if it resolves then problem is on connected variable.
3. If above two points not resolves, then check if channel is forced.