Monitoring Safety Inputs From Hydraulic Valve

Good afternoon All,

I am working on a hydraulic press using RSLogix 5000 V19.
Can I ask how you monitor the feedback from hydraulic valves

Basically I have 2 Load Hold valves with position monitoring, when they get a signal to fire I must see the feedback signals within 500mS

I have tried using the ROUT function but I cant get it to work properly, do any of you guys have any ideas or experience on how this should work

Thank you in advance for your help.

a standard PLC is not designed to carry out safety monitoring - and in my mind should not be used for this funtcion.
the main reason is that the program of ckecking can be too easliy 'deleted' or modified by an unknown operator in the future
look at a PILZ multi or similar and keep the safety circuits away from the PLC.
The PLC should only monitor the 'valve OK' signal with a fault tripping out the external safety.
I hope yo are not putting the E/stop and guards aslo through the PLC - this does not meet the European standards either

EDIT
A safety PLC is also an option
but
500mS is too slow for a press

Sorry I didn't make it clear I am using a safety PLC
Safety Compact Logix

I have not used that Safety PLC.
I still suggest that 500mS is too slow
this is Half a second for the spool of a valve to have moved to the stopped position - and - appart from the other equipment the total stopping time would be well in excess of that.
I understand it is hydraulic, but these must be scoped into your safety - risk analysis.
May not be an issue if you are using mechanical guards - definately will be if you are using a light grid as your primary safety device

Thank you for your reply Ian, that is why I am looking for alternative solution as the timing in the ROUT function is set at 500mS

Bump...

How long of a time delay do you need? (Jeez, I would think that 500ms is an eternity). Automation Direct has time delay safety relays.

Schui,

Like you, we use CompactLogix Safety PLC's on 2 hydraulic presses and several of our mechanical presses.

Take a look at the ROUT (Redundant Output) or the CROUT (Configurable Redundant Output) function blocks. Either of these blocks should do what you need by both controlling the outputs and monitoring the feedbacks. The ROUT has a fixed 250ms feedback max discrepancy time and CROUT is adjustable.

Like iant said, 500ms is pretty long. I try to keep everything 100ms or less in my safety applications.