Description - PENN Controls - LIT-1900898 - C450RCN - System 450 Multi-Purpose Modular Control System - C450RCN Reset Control Module Two Relay Outputs

Attaining Equal Runtimes on Redundant Mechanical Systems Application Note
Product name
C450RCN Reset Control Module Two Relay Outputs
Document type
Application Note
Document number
LIT-1900898
Revision date
2020-04-15
Important: Use the System 450™ control module only as an operating control. Where failure or malfunction of the System 450 control module could lead to personal injury or property damage to the controlled equipment or other property, additional precautions must be designed into the control system. Incorporate and maintain other devices, such as supervisory or alarm systems or safety or limit controls, intended to warn of or protect against failure or malfunction of the System 450 control module.

Refer to the System 450 Series Modular Control Systems with Reset Control Modules Technical Bulletin (LIT-12011842), the System 450 Series Modular Controls Product Bulletin (LIT-12011458), and the installation instructions for product specifications, detailed installation procedures, and important product safety information

The C450RCN-x Reset Control Module enables you to keep the runtimes approximately equal on applications with redundant equipment. This example uses two similar cooling units with a space setpoint of 55°F. To attain equal runtimes on both cooling units, you must use the Reset function (rES) in conjunction with the balancing function (bAL).

Figure 1. C450RCN-x Control Module Attaining Equal Runtimes on Redundant Mechanical Systems

In this example, Sensor 2 (Sn-2) is the space sensor. Sensor 1(Sn-1) must be installed, although the physical location of Sn-1 is not important in this example. The desired 55°F space temperature setpoint is attained by setting both the minimum setpoint (MNSP) and the maximum setpoint (MXSP) to 55°F. The control cycles the output relay (unit) with the fewest hours, keeping the runtime hours approximately equal.

Figure 2. Status and UI Setup Screens for the C450RCN-x Control Module Attaining Equal Runtimes on Redundant Mechanical Systems Example