Encorp GPC Programming

[Dave Loucks]

The typical method of programming the GPC was to use the software provided by Encorp.  This software connected to the GPC using the Lonworks LonTalk protocol.  Since LonTalk required an external converter (usually RS-232 to LonTalk twisted pair), some users requested an alternate method of changing setpoints that did not require the LonTalk gateway.

Since the GPC also included a Modbus RS-485 port and since many of the setpoints within the GPC were memory mapped within the Modbus register map, changing setpoints via Modbus is possible.

A simple program loader that used the Modbus protocol was developed that can be downloaded from http://www.pps2.com/communications/DGMonitor.htm. 

A user manual explaining how to use this software can be reviewed http://www.pps2.com/communications/files/DGHelp.doc.

The source code for the VB 6.0 application can be downloaded here:
http://www.pps2.com/communications/files/DGMonitorSourceCode.zip

Complete Cross Reference of LonWorks SNVTs to Modbus Registers used in GPC:
http://pps2.com/communications/files/GPC/rev2-0%20control%20variables.xls

(Limited) Cross Reference of SNVT to Modbus Register used in this VB Program:
http://pps2.com/communications/files/GPC/Tagname%20Cross-Ref.xls