John_R Posted August 2, 2018 Report Share Posted August 2, 2018 Hey All, Trying to resolve an issue that's got me thinking outside the box. Looking for opinions as to whether my idea is acceptable. We have a machine that I recently upgraded from relays to PLC. I'm using a V570 with all remote I/O, EX-D16A3-TO16 IO-DI16 IO-RO16 With the exception of an encoder that comes straight to a V-200-E1B snap I/O. Our management is on a Data Collection kick and they want runtime info spoon fed to them. I've accommodated their needs by writing things to a data table, and retrieve it to excel using DataXport. All is good so far... But the machine has setup changes a dozen times a day where the operator must power down and LOTO. I cannot control nor predict when the machine is powered down, and obviously I cannot talk to the PLC with no power. You all with me so far? So, my thought is to supply power to the PLC only, from a source before the lockout disconnect. Everything else is safely locked out, 480v to motors, control power to other devices, etc. just power to the PLC for communications I'll have a relay that monitors power after the disconnect, and when it turns off it will give an input to the local snap I/O where I'll switch to an HMI display with a black backround and the phrase "Power is Off" dancing around like a screen-saver. Anybody out there see a safety issue with this? JohnR Quote Link to comment Share on other sites More sharing options...
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