Description - PENN Controls - LIT-1900860 - C450CPN - System 450 Multi-Purpose Modular Control System - C450CPN Standard Control Module One Analog Output

Differential Control to Replace a Standard Differential Pressure Transmitter Application Note

PENN Controls
Product name
C450CPN Standard Control Module One Analog Output
Document type
Application Note
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Revision date
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 Standard Control Modules Technical Bulletin (LIT-12011459), 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.

You can use System 450 to measure a pressure difference across pumps, heat exchangers, and similar devices where you want to control a device using differential pressure. Compared to a Differential Pressure Transmitter (DPT), installing System 450 is simpler, requires less hardware, and is less labor-intensive, saving time and money. System 450 parameters are easy to configure and readjust, if necessary, making it much more flexible than a DPT.

A DPT requires a manifold, a bleeder valve, isolation valves, a bypass valve, and associated piping. Only the isolation valves are required for a System 450 installation.

In this example, a System 450 control system with two identical pressure transducers is set up to control pump speed based on the pressure differential detected between the Sn-1 and Sn-2 transducers. When Sn-1 and Sn-2 are the same Sensor type, the Differential Sensor (Sn-d) is automatically enabled and available for selection when you set up the control system outputs.

When the Differential Control sensor (Sn-d) is referenced, the differential sensor value is always equal to Sn-1 minus Sn-2.

The sensed differential value (Sn-d) between Sn-1 and Sn-2 is displayed in the System Status screens as either a temperature differential value (dIFT), pressure differential value (dIFP), or humidity differential value (dIFH). For example, if Sn-1 has a value of 58 andSn-2 has a value of 55, Sn-d has a value of 3 (58 minus 55).

Figure 1. Comparison of a System 450 Differential Pressure Control to a Differential Pressure Transmitter Using a Variable Speed Water Pump to Regulate Differential Water Pressure

Figure 2. UI Screen Parameters Needed to Set Up Sensors for Differential Pressure Control