I have a basic question related to the safety output on SLX.
I have four outputs generated in SafeLogic, and two outputs have direct signal paths.
The second type safety output depends on the state of a process variable as well as the logic in Safe Designer.
Is this statement true?
Here’s what I’ve observed:
I have one output that behaves as described above. When the process variable changes to false, it directly switches off the safety output. Additionally, when the safety logic is violated, the output switches off regardless of the process variable’s state.
However, this does not seem to work for the second output, which is, in fact, the negation of the first one. While the second output behaves correctly when safety is violated (it switches on), it does not respond to changes in the process variable.
the statement seems true.
The “direct” setting means, that the standard application can activate the channel.
The “via SafeLogic” setting means, that the stardard application has no access to the channel, except the CPU to SafeLOGIC communication.
Here is the information from Automation Help.
Maybe it has something to do with the ReleaseOutput? Please make sure you use the correct channel in the I/O mapping. You might as well check the logger for any information.
The channels are identical:
I can achieve this using a simple FromCPU_BOOL variable, but it consumes some processing time, causing the output to be delayed compared to the direct signal path version. The outputs need to be released simultaneously, but I can’t find a way to delay the direct one.
It’s correct. One variable must drop to false and the other to true when safety is violated. Both are identical and are treated identically in SafeDesigner (the outputs are released in the same way).
