Firejo
Member
Does anybody know if it’s possible to clear the ARP table in a CompactLogix PAC without cycling power or waiting for it to clear itself? From what I’ve been able to find in Google-land the answer is no but before I go to plan “B” (cycling power to the processor whenever I need to change to a new device to talk to) I thought I’d give the brain pool a chance. I’m building a setup that will be used to test our Protocol to I/O modems in which part of the process is testing all of the I/O points on a given remote as well as calibrating the analog outputs. This involves communicating to a protocol master from the CompactLogix issuing commands to the specific I/O remote. The problem comes in when I change from one Protocol master to another. They both have the same IP address but different MAC addresses and as it is now it takes anywhere from 10 to 20 minutes for the ARP table to dump the first master and find the second one. Long story short is that I can cycle power on the PAC but if there is a way to use logic to clear the table then I can automate it and make it… well let’s just say “production technician proof” (all due respect given). OK, so I spent a couple of hours trying to figure out why I couldn’t change from one master to another until I realized that the ARP table was getting in the way.