4
3 Communication Protocols
The MJ-5 Control Panel is designed to be used in a network of intelligent power control devices communicating
with a supervisory device or remote terminal unit (RTU). Each device on the network has a specific communications
address assigned to allow messages to be directed to and from the device. Messages are transmitted from the RTU to
all devices and only the device with the specified address will respond. The MJ-5 Communications Module supports
the following protocols. Refer to the documents listed for details about the protocols.
Distributed Network Protocol (DNP 3.0). (See User’s Group website: www.dnp.org)
The Cooper 2200 Protocol (with or without address byte)
The 2179 Protocol ( Based on the PG&E Protocol)
4 Installing the Communications Module in MJ-5 Control Panels
The MJ-5 Communications Module is mounted directly on the MJ-5 Main Processor Board. Follow these steps to
install the communications module. Details are provided in the sections below.
1.
Turn off power to the MJ-5.
2.
If in a regulating device, then disconnect the polarized disconnect switch (PDS).
3.
Install the communications module.
5 Cabling the Communications Module to the Power System
Connect the communications modules using the recommended cable as described in sections 5.1 to 5.3 below. The
following sections provide some general guidelines for cable selection and explain the different cable parameters.
Make connections between the device and the communications unit with the appropriate connector.
Typically, RS-485 requires custom wiring to the other devices. Consult the device’s pin assignments to determine
the applicable connections. Typically, a DB-9 (DE-9) will be needed for making RS-232 connections to the RTU,
personal computer, or other device. Use the supplied Phoenix Contact Screw Terminal Block (MSTBT 2, 5/8-ST-5,
08) for connections to the RS-232/485 interface. Use an ST optical connector when making connections to the fiber
optic interface.
Though the cabling for the Fiber Optic and the RS-232-/485 interfaces may be done and either interface may be
made available for communication, only one of the interfaces may be used at a time.
WARNING
120 volts on terminal block, leads, and
inside control panel housing.
May result in death or serious injury
from electric shock including equipment
damage.
Disconnect all power sources before
opening the control panel.
