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I/O Network Boards and Peripherals Hardware Overview • 2-7
The PAK can control up to 4 condenser fan groups
containing up to 8 total condenser fans. The PAK con
-
denser control strategy is sequential TD control with set-
point/deadband using ON and OFF delays.
The PAK has a compressor/condenser interlock fea-
ture that will override TD control and force the condenser
fan
s to stage off using the TD control OFF delay when all
compressors are off. This feature can be disabled with an
Enable/Disable setpoint or when the discharge pressure is
above a configurable setpoint.
The MultiFlex PAK boards consist of two circuit
boards: a bot
tom layer with 16 combination digital/analog
inputs, and a plug-in top layer which contains a combina-
tion of 8 relay outputs and 4 digital DC voltage outputs.
The analog outputs on the Multiflex PAK drive solid
state relays to control the fan stages. The relays control the
com
pressor groups.
The communication interface is RS485 I/O using
the
Standard Extended Address Form for Emerson Retail
Solutions Distributed Controllers. Currently, the PAK is
designed to interface with the Emerson Retail Solutions
E2 controller.
Figure 2-10
- MultiFlex PAK
1 Input Power (24VAC)
2 RS485 I/O Network
3 PAK Inputs 1-8
4 PAK Inputs 9-16
5 Network ID Dip Switches (S3)
6 Network Type Dip Switches (S1, S2)
7 Board Status LEDs
(Code A, Code B, General Status)
9 RS485 Termination Jumpers
10 Hand-Held Terminal Jack
11 Relay Output Connectors
12 Relay Output Fuses
(2A Rated, 250V Slow-blow)
13 Relay Status LED
14 Relay Fail-safe Switches
8 DC Power Outputs
(3 at +5VDC, 1 at +12VDC)
15 PAK Analog Outputs 1-4
16 Network Status LED
2.2.3 The MultiFlex ESR Board
The MultiFlex ESR Valve Regulator board (P/N 810-
3199), shown in Figure 2-11, is an
RS485 I/O Network
electronic stepper valve regulator cap
able of driving up to
eight stepper motor valves, which are typically used to
control temperature.
Figure 2-11 - MultiFlex ESR Board Layout
8
3
7
24VAC CT 75 VAC Power Input
Valve Connectors (8)
I/O Network Input
Termination Jumpers
Network Address Switches
General Status LED
1
5
2
3
4
6
7
8
HHT Jack
TX and RX LEDs
9
10
Open LED (8)
Close LED (8)
9
10
The MultiFlex ESR uses suction side variable-position
evaporator regulators (ESRs) to vary evaporator pressure
for an entire circuit and is an alternative to mechanical
EPR control.
The MultiFlex ESR receives input
data from a Emer-
son Retail Solutions E2 controller (via the I/O Network)
and then regulates
the stepper valves according to the data
from the E2.
Each MultiFlex ESR board requires a Class 2, 80VA
24
VAC center-tapped transformer for power. Emerson
Retail Solutions transformer (P/N 640-0080) is a multi-
tapped primary transformer that may be used with the
MultiFlex ESR board.
2.2.4 Hand-held Terminal (P/N
814-3110)
The Hand-held Terminal (HHT) is used by manufac-
turers and service technicians to diagnose and test several
of
Emerson Retail Solutions' existing and legacy products.
The HHT can be used on any Emerson Retail Solutions
product with an RJ-11 connector. The most common appli-
cations include:
• All MultiFlex I/O boards and the 8ROSMT
• All Gateway boards
• Stand-alone MultiFlex boards (RTU, RCB, PAK,
CUB)
• CCB and CC-100 case controllers
The HHT does not require a separate power source.
The uni
t is powered from the RJ-11 connector on the
peripheral equipment. The HHT includes a standard male