Posted 16 Dec 2021 Hey all, So I am looking for some assistance because I am not understanding how the tags on an HMI and within a PLC are linked. There are no 'physical' buttons, just what is on the HMI. It is controlling a chiller. Communicates over Modbus TCP/IP. The PLC is an IDEC. I have some-what worked out how other tags are working when they are words being passed back and forth, but this one has me stumped. I've attached a few screenshots for referral. It looks like the run and unload buttons for the chiller are a single bit/BOOL toggle (but the chiller running latches itself in the PLC when the chiller starts to run). The stop buttons appears to be a parent for the single bit/BOOLs and when it is pressed it resets them all both on the HMI side and within the PLC side. Share this post Link to post Share on other sites
Posted 5 Jan 2022 I'll gove my ideas, so here I go: It appears the Weintek is acting as a Modbus Master, and writing to the IDEC (in second pic) as 47652.00/ Read register 47652 Bit 0. Post here if the forum can provide more info Share this post Link to post Share on other sites
