Specifications

103
Table 97 — Controls Expansion Board (CEM) Inputs
SCROLLING MARQUEE — This device is the keypad in-
terface used to access the control information, read sensor
values, and test the unit. The Scrolling Marquee display is a
4-key, 4-character, 16-segment LED display as well as an
Alarm Status LED. See Fig. 26. The display is easy to operate
using 4 buttons and a group of 11 LED’s that indicate the
followingmenustructures:
• Run Status
• Service Test
• Temperatures
•Pressures
• Set points
• Inputs
• Outputs
• Configuration
• Timeclock
• Operating Modes
•Alarms
Through the Scrolling Marquee the user can access all the
inputs and outputs to check on their values and status. Because
the unit is equipped with suction pressure transducers and
discharge saturation temperature sensors it can also display
pressures typically obtained from gages. The control includes a
full alarm history, which can be accessed from the display. In
addition, through the Scrolling Marquee the user can access a
built-in test routine that can be used at start-up commission and
to diagnose operational problems with the unit. The Scrolling
Marquee is located in the main control box and is standard on
all units.
SUPPLY FAN — The 20 to 50 ton units are equipped with
two 15 x 11-in. forward-curved fans. The 60 ton units have
three 15 x 11-in. fans. They are on a common shaft and
are driven by single belt drive 3-phase motor. The fan is con-
trolled directly by the ComfortLink™ controls.
VARIABLE FREQUENCY DRIVE (VFD) — On variable
volume units, the supply fan speed is controlled by a 3-phase
VFD. The VFD is located in the fan section behind a remov-
able panel as shown in Fig. 20 and 21. The VFD speed is
controlled directly by the ComfortLink controls through a 4 to
20 mA signal based on a supply duct pressure sensor. The
inverter has a display, which can be used for service diagnos-
tics, but setup of the supply duct pressure set point and control
loop factors is done through the Scrolling Marquee display.
The VFD is powered during normal operation to prevent
condensation from forming on the boards during the off mode
and is stopped by driving the speed to 0 (by sending a 2 mA
signal to the VFD).
The A series units use ABB ACH550 VFDs on all 230-3-60
and 460-3-60 units. An ABB ACS800 or Toshiba E3 VFD
is used on 575-3-60 units. The interface wiring for the
VFDs is shown in Fig. 27. Terminal designations are shown in
Table 99.
Table 98 — IGC Board Inputs and Outputs
POINT
NAME
POINT DESCRIPTION
I/O POINT
NAME
PLUG AND PIN
REFERENCE
SIGNAL PIN(S) PORT STATE
INPUTS
SFS Supply Fan Status switch DI 1 J7, 1-2 2 0 = 24vac, 1= 0vac
DMD_SW1 Demand Limit - Redline DI 2 J7, 3-4 4 0 = 24vac, 1= 0vac
DMD_SW2 Demand Limit - Load Shed DI 3 J7, 5-6 6 0 = 24vac, 1= 0vac
PRES Pressurization DI 4 J7, 7-8 8 0 = 24vac, 1= 0vac
EVAC Evacuation DI 5 J7, 9-10 10 0 = 24vac, 1= 0vac
PURG Purge DI 6 J7, 11-12 12 0 = 24vac, 1= 0vac
IAQIN Indoor Air Quality Switch DI 7 J7, 13-14 14 0 = 24vac, 1= 0vac
AN7 J6, 1-3 2 (1 = loop power) (0-20mA input)
DMDLMTMA 4-20mA Demand Limit AN8 J6, 4-6 5 (4 = loop power) (0-20mA input)
EDTRESMA 4-20mA Evaporator Discharge SP Reset AN9 J6, 7-9 8 (7 = loop power) (0-20mA input)
OAQ Outside Air CO
2
Sensor AN10 J6, 10-12 11 (10 = loop power) (0-20mA input)
SPRESET SP Reset milliamps AN10 J6, 10-12 11 (10 = loop power) (0-20mA input)
POINT NAME POINT DESCRIPTION
CONNECTOR
PIN NO.
INPUTS
RT 24 Volt Power Supply R1,C
W Heat Demand 2
GFan 3
LS Limit Switch 7,8
RS Rollout Switch 5,6
SS Hall Effect Sensor 1,2,3
CS Centrifugal Switch (Not Used) 9,10
FS Flame Sense FS
OUTPUTS
CM Induced Draft Motor CM
IFO Indoor Fan IFO
R 24 Volt Power Output (Not Used) R
SPARK Sparker —
LED Display LED
Run Status
Service Test
Temperature
Pressures
Setpoints
Inputs
Outputs
Configuration
Time Clock
Operating Modes
Alarms
Alarm Status
ENTER
MODE
ESCAPE
Fig. 26 — Scrolling Marquee