I doubt that there's an OPC server available for the 620.
The page below is from the introduction to the 620 reference manual. It seems that the communications link for the 620 does not use a conventional industrial protocol, but is a proprietary protocol for data bit or status bit transfer peer to peer between 620 processors.
The page below is the introduction page from the 620 LC reference manual, available as a scanned image (not text searchable) pdf from
http://www.pscsnapshot2.com/imc/scripts/silverware.exe/showplin@d:/dfs/elevclients/IMC/elevator.fxp
(registration required for access)
--------------- page 6, 620 LC reference manual ------------
CONTROL NETWORK:
Peer-To-Peer With A Single Twisted Pair To Multiple Processors
From 620 LC Reference manual document # MAS-8990B, dated Dec 1995 (page 6 pdf)
IPC 620 Control Network is a high-speed, cost-saving method of interconnecting programmable controllers for I/O status or data transfer. The Control Network Module (CNM) installed in an option slot of a 620 programmable controller enables information to be
transferred between as many as seven other processors which contain CNM's.
Installing the Control Network Module in a processor option slot links the processor into a highly reliable peer-to-peer network for interlocking processes and control. The processors are interconnected by a single twisted pair cable in a multi-drop topology. Each processor can transfer up to 32 bits per input status scan onto the network, keeping all processors informed
of I/O status and data on a real-time basis. By setting the network to a maximum of four CNM's, a processor is capable of transferring 32 or 64 bits onto the network.
SIMPLICITY AND FLEXIBILITY
Control Network automatically delivers 256 bits of user-selected information among as many as eight programmable controllers. See Table 1. All the firmware and hardware necessary for
inter-communication over the network cable is contained in the Control Network Module. No programming is required to implement the information transfer between the CNM and the network. The Control Network Module is simply placed in a 620 System Processor,
eliminating the need for additional I/O modules and individual hardwiring between I/O for sharing control status among multiple processors.
The user selects whether to send I/O status information or data register contents for each processor on the network. The processors can be located over a trunk distance up to 8,000 feet. The single cable bus is wired directly to the CNM module, replacing the many individual wires required by hardwired I/0.
SAVES SOFTWARE AS WELL AS HARDWARE COSTS
The Control Network operates without user programming which reduces programming time and saves user memory. Operation of the Control Net-work is determined by DIP switch settings rather than programming instructions inserted in user memory. After DIP switch settings are made the module is installed in a 620 processor option slot. The processor can communicate with the network without complicated check-out procedures.
Cost factors, such as I/O modules, associated housings, wire runs and panel space, which con-tribute to the cost of transferring data among hard-wired processors are also reduced by Control Net-work. Control Network offers the reliability and speed of serial data transmission which is necessary for real-time control.
