9
Random Start
A startup delay between 0 and 9 seconds ensures that all units do not come on line at the same
time.
Full Digital Communications
An optional internal communications interface allows the communication of alarms and analog
data to a monitoring system. Industry-standard RS-232 or RS-485 serial communications are
available for applications requiring direct interfacing to other devices. The modem version main-
tains compatibility with legacy products including the GCC-9000/780 Series (Group Communi-
cations Controller). With the availability of the heat trace data at the user’s fingertips, historical
trending of temperatures, power consumption, or other parameters are available for analysis
and system optimization.
CSA C/US and Factory Mutual Approved
The 920 series of controllers is approved for Class I, Division 2, Groups A,B,C,D and Zone 2
hazardous locations, making it ideal for direct installation in the field. This can save the signifi-
cant expense of wiring back to a centrally-located electrical distribution center.
1.3 Modular Components
The 920 series controller is made up of a number of building blocks, allowing the ultimate in
design flexibility. Each component’s primary function is described below.
1.3.1 CONTROL MODULE
The 920 control module forms the heart of a single- or dual-point heat trace control solution.
Each plug-in module provides all of the intelligence required to control and monitor two inde-
pendent heat trace circuits. It includes indicators for alarm and output status and a connector for
use with a 920 Operator Console. An internal connector is provided to plug into an optional com-
munications interface.
The control module packaging provides a rugged, vibration-proof design. Once it is plugged into
a terminal board, the module is fastened using the two captive screws included as part of the
rear cover. It is important that these two screws be securely fastened whenever the module is
powered.
1.3.2 TERMINAL BOARD
The terminal board eases maintenance and troubleshooting by providing a termination point for
all of the low-voltage signals. The 920 control module may be installed or removed without dis-
turbing the field wiring. Temperature sensor, communications, and alarm control wiring are con-
nected to the lever-operated spring terminals, providing gas-tight, vibration-resistant
connections.
1.3.3 OPERATOR CONSOLE
A large, easy-to-read alphanumeric display and menu-driven interface ease controller configura-
tion and eliminate the need for an external programmer. The console may be left installed perma-
nently or may be installed temporarily for display/setup during maintenance and
troubleshooting. Access is available for all monitored parameters, programmed values, and
alarm information. Enhanced security is provided by password protection.
The unique design of the operator console allows it to be installed or removed under power, even
in hazardous areas.
1.3.4 SWITCH INTERFACE
Universal single-phase current monitoring, single- or 3-phase ground-fault detection, and volt-
age monitoring are provided by the Switch Interface (
SIS/SIC) module. One device is required for
each control point, and two versions are available:
SIS for use with SSRs, and SIC for use with the
contactor. Both units also incorporate a universal power supply, allowing operation directly from
100 Vac to 277 Vac. Use with higher trace voltages is also possible, using a separate power
source or a small step-down transformer.
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