All,
I have a hopefully simple question regarding programming safety routines.
Say we have 2 EStop loops wired in parallel configured to be dual-channel inputs. They are wired to points 0 and 1 on a 1734-IB8S module.
In the module configuration, I set these inputs to be dual-channel equivalents with a discrepancy time of 250ms. They are powered from a power supply and are not connected to the pulse test outputs.
When I am using these Estop inputs in my Safety routine, do I need to use a DCS (Dual Channel Stop) instruction (or similar instruction) to monitor the inputs? Or am I safe just using both inputs in parallel since I have the IB8S module configured to already check for input discrepancy?
Basically, does one need to check for discrepancy in both the hardware configuration AND the software programming, or are instructions like DCS meant to be used when one is not able to do this in the input module?
Thanks
I have a hopefully simple question regarding programming safety routines.
Say we have 2 EStop loops wired in parallel configured to be dual-channel inputs. They are wired to points 0 and 1 on a 1734-IB8S module.
In the module configuration, I set these inputs to be dual-channel equivalents with a discrepancy time of 250ms. They are powered from a power supply and are not connected to the pulse test outputs.
When I am using these Estop inputs in my Safety routine, do I need to use a DCS (Dual Channel Stop) instruction (or similar instruction) to monitor the inputs? Or am I safe just using both inputs in parallel since I have the IB8S module configured to already check for input discrepancy?
Basically, does one need to check for discrepancy in both the hardware configuration AND the software programming, or are instructions like DCS meant to be used when one is not able to do this in the input module?
Thanks
