Johnson Controls MR12DR230-1C - User Manual

Electrical Control Cabinets
Including digital controller
I
ntroduction
Designed to facilitate installers work, this range
of electrical cabinet is intended for use in cold
rooms working at positive or negative
temperatures and powered either with single
phase or three phase power supply.
Based on specifically designed controllers, it
incorporates all control functions as required by
modern cold room units, such as compressor
control, defrost management, fan management,
alarm function and solenoid valve for “pump
down”.
It also includes all the safety equipment needed
such as circuit breakers for the compressor and
for the controller.
Particular attention has been given to the
accessibility so that the installation time will be
reduced to a minimum. Space has been left
available for customisation.
12 modules (front) and 36 modules (back)
models
Features and Benefits
!
Power rating from :
0,37 to 1,5 kW in single phase
1,5 to 7,5 kW in three phases
Cover most of standard applications.
!
Standard DIN rail components
Easy maintenance and servicing.
Availability of components.
!
Most wiring integrated on the controller
Increased quality and reduced space occupancy.
!
Specifically designed controller to
manage Pump Down
Better match application need.
!
Accurate and interchangeable
IP 68 sensor
Accurate control performance.
No re-calibration needed.
!
IP 65 standard DIN polycarbonate cabinets
High mechanical resistance.
Installation in harsh environment.
!
Integrate circuit breaker for motor and
controller
No time lost defining appropriate protection
!
In field extension
Possibility to field connect a condensing fan or a
door frame heater.
!
Main Switch
To power down the whole cabinet.
Increased safety protection.
Refrigeration Controls Catalogue
Catalogue Section
9
Product Bulletin
CR1
Issue
0101
© 2000 Johnson Controls, Inc. Catalogue Section 9
Order No. P-CR-E

Johnson Controls MR12DR230-1C Specifications

General

Product Type	Controller
Input Voltage	24 VAC
Frequency	50/60 Hz
Enclosure Rating	IP20
Communication Protocol	BACnet MS/TP
Inputs	12
Storage Temperature	-40°F to 185°F (-40°C to 85°C)

Summary

Positive temperature cold room

Wiring diagram

Negative temperature cold room

Negative temperature cold room with three phase defrost

Negative temperature cold room with three phase defrost and evaporator fan

Description of each parameter

Setpoint

Defines the relay cut OFF point for temperature control.

Hysteresis (Hy)

Difference between compressor OFF and ON temperatures.

LL;HL Lower & Higher setpoint limit

Limits for adjusting the setpoint value.

Anti short cycle protection (CC)

Prevents compressor from switching ON/OFF too often.

Deep freezing time (Co)

Time compressor is forced ON for a deep freezing cycle.

High temperature alarm (AH)

Alarm value relative to setpoint for high temperatures.

Low temperature alarm (AL)

Alarm value relative to setpoint for low temperatures.

Alarm differential (Ad)

Difference to avoid alarm oscillations.

Alarm time delay (At)

Delay between alarm detection and activation.

Defrost function (dF)

Selects type of defrost (electric or hot gas).

Defrost end function (dE)

Selects defrost termination type (timer or temperature).

Defrost termination temperature (dt)

Temperature to end defrost when using temperature-based termination.

Defrost interval time (di)

Time between two subsequent defrost cycles.

Max defrost duration (dd)

Maximum duration for a defrost cycle.

Dripping time (dC)

Time after defrost to allow evaporator to drip.

Description of each parameter (continued)

First defrost cycle after power-on (dU)

Display during defrosts (dP)

Delay displayed temperature after defrost (dr)

Digital input function (iF)

Digital input time delay (id)

Fan operating function (FF)

Fan start-up delay after defrost end (Fd)

Fan start temperature after defrosts end (Fr)

Thermostat operating function when sensor failure (SF)

Offset thermostat sensor (So)

Temperature units (Un)

Display updating time delay (PU)

Characteristic of the general circuit breaker

Characteristic of the circuit breaker for motor (three phase models only)

Repair, Replacement and Spare-parts

Specifications