5
RSMD Technical Guide
OVERVIEW
RSMD Overview
Features & Applications
The Refrigerant System Module for Digital Compressors
(RSMD) can monitor and control up to two compressors and
condensers. The compressors can be in either a tandem or
non-tandem configuration. The module is designed for R410-A
refrigerant.
NOTE:
The RSMD is for units that match all of the
following criteria:
1. One or two circuits.
2. Compressors may be any mix of fixed, two-step,
and digital.
3. Reheat is present on the first circuit.
The RSMD is connected to the VCCX2 Controller. Up to four
RSMD’s can be connected, depending on the size of the system.
There are two E-BUS Expansion Ports which allow the use of
communicating sensors and the E-BUS Modules.
The RSMD provides three analog inputs, four binary inputs,
five relays, and two analog outputs. See
Figures 2 & 3, pages
8 & 9
for wiring.
The RSMD Module provides the following:
• Modulates the Compressors to satisfy the Suction Coil
(Saturated) Temperature. The Suction Coil (Saturated)
Temperature Setpoint is reset by the VCCX2 Controller
to maintain the Supply Air Temperature during Cooling
mode. During Dehumidification mode, it controls the
Compressors to the Suction (Saturation) Temperature
Setpoint.
•
In Heat Pump Heating mode, the RSMD modulates and
stages the compressors to maintain a given Supply Air
Temperature Setpoint.
• Modulates the Condenser Fan or Valve to maintain the
Head Pressure Setpoint.
• Provides alarms and safeties for the Compressor and
Condenser operation.
•
Allows connection of the Modular Service Tool SD to the
module when required communication wire is run to the
VCCX2 Controller.
• Provides a 2 x 8 LCD character display and four buttons
that allow for status of system operation, system setpoints,
system configurations, sensors, and alarms, and to change
the module’s address, if necessary.
Summary of Contents for RSMD
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