Emerson E2 TD3 Temperature Display, Control Link CD Case Display, Wiring, Door Switches

11.3.3.2Door Switches

Walk-In Box freezers are often equipped with door switches that disable the evaporators when the door is open. The E2 is capable of reading a digital door switch input and controlling the freezer appropriately.

When a door switch opens, the E2 will shut off the refrigeration solenoid and the fans (if active) and turn the lights ON.

11.3.4 Fan Control

A circuit’s circulation fan is always ON when the cir- cuit is in refrigeration mode. Its state during defrost is determined entirely by how the application is programmed by the user. You may choose to set the fan either ON or OFF for each phase of a defrost cycle (Pump Down, Defrost, and Run Off). If you choose to keep fans off for the entire defrost cycle, you may also choose to program a delay that will keep the fan from activating for a fixed amount of time after the cycle ends.

Fans are locked OFF during clean mode.

11.3.5The TD3 Temperature

Display

The TD3 is a case display that is designed to monitor three types of temperature sensors. The compact unit is mounted on the face of a refrigeration case and displays, by default, the discharge air temperature. Pressing the function button repeatedly allows you to view the tem- perature of EmersoRetail Solutions’ product probe, the defrost termination value, and then back to the discharge air temperature.

The TD3 has a status light that is controlled by the E2 controller. A green status light means that the status is okay while a red status light indicates alarm.

This case display can be configured to show either the discharge air temperature (default), the product probe tem- perature, or the defrost termination temperature.

The TD3 communicates with the E2 controller via the Echelon Network and in turn the E2 adjusts the circuit’s temperature or defrost status.

11.3.6The Control Link CD Case

Display

The Control Link CD is mounted inside the refrigera- tion case and serves as a point to which the sensors are wired. A single RS485 communication cable links the case display back to the E2 controller. Additionally, an optional remote display can be added to the control module to pro- vide a local indication of case temperature and operational mode that is remote from the control module.

11.3.7 Wiring

Wiring a case circuit so that it may be controlled by a Standard Circuit application primarily involves wiring all temperature sensors to 16AI Analog Input Boards and wir- ing the valves and other devices on the case to a relay out- put board such as an 8RO Relay Output Board.

Figure 11-5shows a typical case in a circuit and the devices that must be wired for each. Follow the guidelines below to wire the circuit to the E2 I/O Network:

11-8 • E2 RX/BX/CX I&O Manual 026-1614 Rev 4 5-JAN-2013