I've got a York Codepak chiller with an MCC (microcomputer control center, documentation # 160.65-PA2.1 ) that was originally tied to an LDC-34 ISN controller as its remote display interface (circa 1993). The operators have been running this plant in manual since day 1. I don't believe this interface has ever worked, as the MCC has an RS-422 interface and the LDC-34 has an RS-485 interface.
Our responsibility on this job is to reset the CHWS setpoint via an input on the LDC-34. The ISN takes the signal, and the desired result shows up on the lcd screen, but it doesn't make its way to the MCC.
I have a hunch that a simple RS485<->RS422 converter would take care of this problem...
I have a feeling they engineered the system having the LDC-34 interface with a different panel than what was supplied with the chiller.
Our customer does not wish to bring JCI/York into the mix (I don't blame them).
Has anyone dealt with such beasts before?
I'm thinking one of these could solve the issue: http://www.rs485.com/prsfc44t.html
Any comments appreciated.