Rkc Instruments Z-Com-A-55 122D Extension Module

RKC Instruments Z-COM-A-55/122D SRZ PLC Communication Extension Module is a 24 V DC RS-485 extension device for the SRZ control family, enabling additional host communication by linking Z-TIO, Z-DIO, and Z-CT modules to a single SRZ processor. It is powered from 21.6 to 26.4 V DC (rated 24 V DC) and draws less than 30 mA in normal operation, with surge capability under 10 A to handle power transients. This Z-COM module supports up to 16 units in a network and communicates at selectable baud rates of 4800, 9600, 19200, or 38400 bps using either ANSI X3.28 sub-category 2.5B4 (RKC standard) or MODBUS-RTU protocol, providing flexible interoperability with RKC devices and third‑party masters. Designed for industrial environments, it operates from -10 to 50°C and tolerates supply ripple up to 10% p-p; a power loss of 4 ms or less will not affect control actions, ensuring quick recovery. The Z-COM extension is a specialized data conduit within the SRZ system, serving as the communication backbone for extended configurations that require multiple field devices and robust Modbus/RS-485 communication capabilities in a compact form factor, and its 122D variant designation identifies this specific configuration of the A-55 family.