Series Six Communications Control Module Type 2 (CCM2), Dual Serial RS-232C / RS-422, 300 bps to 38.4K bps

What this part is:
GE Fanuc IC600CB516A, a Communications Control Module Type 2 — CCM2 — for the Series Six programmable controller. It is a serial communications board: it gives the Series Six CPU two serial ports so an outside intelligent device can read and write the PLC’s memory. Typical partners are a host computer, a supervisory or SCADA package, a colour-graphics terminal, a process control system, an operator interface unit, or another GE Fanuc PLC speaking the same CCM protocol. GE’s own drawing number for this board is 44A717545-G01.

Correcting the source data:
Earlier copy for this item called it an “I/O Module”. It is not one, and it does not go in an I/O slot. The CCM2 lives in a dedicated communications slot — on a Series Six 60, 600 or 6000 there is exactly one position that works, the second slot to the left of the CPU power supply. If you need a card to add field inputs or outputs, this is the wrong part. Check the slot before ordering.

Decoding the order code:
IC600 – GE Fanuc Series Six / Series Six Plus familyCB – communications board516 – Communications Control Module Type 2 (CCM2), the earlier generation, which includes tape-cassette load/save functionalityTrailing letter A – hardware revision level, not a function change
Generation matters. CB516 is the earlier CCM2. GE superseded it with the enhanced CCM2 as IC600CB536 and the Type 3 module as IC600CB537; those later boards dropped the tape function and added expanded memory addressing.

Published specifications:
Function: serial communications interface, CCM protocolPorts: two — J1 is a 25-pin D-type female for RS-232D/RS-422; J2 is a 9-pin D-type female for RS-232D/RS-422Line interfaces: RS-232C, RS-422, and RS-422 with clocks (the clocked mode is a CCM2 feature)Data rates: 300, 600, 1200, 2400, 4800, 9600, 19.2K and 38.4K bpsProtocol roles: peer-to-peer, master, or slave. A master can poll up to eight slavesData format: 8 data bits, 1 stop bit, optional parity — odd, even or noneConfigurations: point-to-point and multidropMaximum distance: 50 ft (15 m) on RS-232C; 4,000 ft (1,200 m) on RS-422Multidrop: up to eight slaves on an RS-422 daisy chain; longer runs via modems on RS-232Power required from the rack CPU power supply: +5 V DC, +12 V DC and −12 V DCUnits of load: 17, 4, 4Front panel: four LED status indicators and two centre-off SPDT momentary switches (A and B) for CCM error diagnosticsOperating temperature 0 to 60 °C; storage 0 to 70 °C; humidity 5–95% non-condensingCircuit board 8.15 x 11.0 in (208 x 280 mm); faceplate 12.46 x 1.175 in (317 x 30 mm)

What these specs mean in practice:
Distance decides the port. RS-232 caps at 50 ft, which in practice means a device in the same cabinet or the next one along. Beyond that use RS-422, good for 4,000 ft on decent shielded twisted pair, and RS-422 is also what lets one master multidrop up to eight slave PLCs on a single line. For plant-wide runs or telephone links you put modems on the RS-232 side instead.

An RS-422 wiring caution worth knowing before you commission: the two transmit signals must form one twisted pair and the two receive signals the other. Mixing a transmit and a receive line into the same pair produces crosstalk and intermittent comms. Grounds at each end must also sit within a few volts of each other, or the line drivers can be damaged.

CCM is master/slave, so a slave cannot start a conversation. If the PLC needs to push data unprompted, configure the PLC end as master — or move to a Type 3 module.

What is included:
Circuit board with faceplate, as pictured. Not included: a rack, backplane or CPU rack power supply; a CPU, memory module or control modules; serial cables or mating connector kits for J1 or J2; a modem, terminal, operator interface or host computer; Logicmaster 6 software; or documentation. Cables are built to the connected device’s pinout and are not supplied. GE’s referenced cable types for RS-422 service are Belden 9184, Belden 9302 and NEC 222PISLCBT or equivalent shielded twisted pair.

Installation and setup notes:
Verify the factory-set jumpers JP1 through JP8 and T2/T4/T6/T8 before fitting — several must always sit 1-2, JP4 selects operator-interface enable or disable, and JP6 controls whether +5 V appears on pin 20 of J1. Then set the DIP switches: 9 to 16 configure port J1, 1 to 8 configure port J2, and 18 to 20 set options common to both. Fit terminating resistors only if this module is at the end of an RS-422 link; an intermediate drop must have them removed. The module takes its ID number from the CPU, so use Logicmaster software to set the correct ID in the Series Six CPU scratchpad after installation — a board that appears dead very often just has no ID assigned. Handle as static-sensitive.

Interchange guidance:
IC600CB516 interchanges across its revision letters, so IC600CB516A, IC600CB516C and IC600CB516L are the same catalogue item at different revisions. IC600CB536 is the superseding enhanced CCM2 and IC600CB537 is the Type 3 (CCM3) module — related, not drop-in equivalents. CCM3 adds Remote Terminal Unit (RTU) protocol and process-controller interfacing this Type 2 board does not have; conversely RS-422-with-clocks is a CCM2 feature handled differently on the later boards, so a machine configured for clocked RS-422 should stay on a CCM2. IC600FP536 is the faceplate on its own. Also searched as IC600CB516, IC600CB516L, IC600CB516C, CB-516A, CB516, IC600-CB516A, 44A717545-G01, GE Series 6 CCM2 board and GE Fanuc comm control type 2.