Emerson: Nelson Microprocessor-based Digital Controllers
August 2, 2022
Emerson is offering a low-cost upgrade for electrical heat tracing systems with its Nelson AXPC100-CM-GP and CM-GP microprocessor-based digital controllers that are engineered to accurately control, monitor and maintain the process temperatures of industrial pipes or tanks in ordinary (non-hazardous) locations. Ideal for replacing aging electro-mechanical thermostats, the controllers achieve cost savings by eliminating the need for several components with a design that integrates sensor monitoring, ground fault leakage detection, and remote alarm contacts into a single enclosure.
By installing the controllers, the end-user brings their heating circuit up to the current requirements for ground fault equipment protection outlined in the National Electrical Code and Canadian Electrical Code. As a standard feature, Nelson AXPC100-CM-GP and CM-GP controllers are programmed to trip when leakage current exceeds the specified maximum allowable amount.
Rugged and reliable, these environmentally-hardened controllers are housed in a NEMA 4X fiberglass reinforced, UV resistant polymer enclosure resistant to rain, snow, hose-directed water and windblown dust. Dual-pole heater switching adds to system versatility, making the controllers suitable for heater voltages from 120vac to 277vac. Broad temperature capability of 0° C to 218° C (32° F to 425° F) increases the range of process operations where they can be installed to deliver outstanding performance, safety and energy efficiency.
While the Nelson CM-GP controller comes ready to wall-mount, the AXPC100-CM-GP is configured for direct installation on piping systems. As a stand-alone pipe mounted solution, the AXPC100-CM-GP significantly reduces installation labor and material costs. It employs the field-proven Nelson AX Connection Kit for fast, simple pipe mounting.
As simple to operate as they are to install, both controllers feature a single line, alphanumeric LCD display that enables the use of prompts for set point entry and operation for one heat tracing circuit. LED lights indicate whether or not there is power to the unit, if the heater power is on, and the current status of alarms. Dry contacts will close in the event of an alarm activation, and are conveniently wired to a terminal strip for local or remote use.
GROUND FAULT PROTECTION
Built-in ground fault leakage detection is a key advantage because it does away with the need for a separate EPD branch circuit breaker and costly manual maintenance checks.
Ground faults typically are the result of damaged or improperly installed heat tracing cables that put into contact current-carrying conductors, surfaces or parts with grounded objects. This type of fault can eventually become serious, potentially resulting in overheating, dangerous fires, and shock hazards to employees.
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