Emerson Control Link ACC Service manual

technical bulletin
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Installation Instructions: Control Link ACC Anti-Condensate
Controller System
Overview
The Control Link ACC Anti-Condensate Controller System is a stand-alone controller for anti-sweat
heaters in glass door cases. The Control Link ACC varies anti-sweat heat based on dewpoint and temp-
erature around the door frame, providing effective control of door sweat with the maximum amount of
energy savings.
Components
Control Link ACC (P/N 810-6101)
The Control Link ACC (Figure 1) handles all aspects
of anti-sweat heater control. The on-board processor
calculates the required heater ON time based on the
dewpoint and door temperature readings, and controls
an on-board Triac to activate and deactivate the heaters.
The controller is designed to mount in the mullion
between glass doors or in any other suitable electrical
enclosure, such as a raceway or on the top of the case.
The door frame temperature sensor and dewpoint sen-
sor are mounted remotely and connect to this controller
with cable harnesses.
Four LEDs can be viewed on the front of the plastic
enclosure. They indicate the general status, heater ON/
OFF state, MODBUS network transmit, and MODBUS
network receive.
Dewpoint Sensor (P/N 809-6112)
The Control Link ACC uses an external dewpoint sensor
(Figure 2) to measure the dewpoint of the outside air next
to the case doors. This sensor is typically mounted directly
above or to the side of the case doors.
The Dewpoint Sensor is supplied in a mountable enclosure
with a12-foot jacketed cable with a four-wire pigtail con-
nects the Control Link ACC to the dewpoint sensor.
Figure 1 - Control Link ACC
Figure 2 - Dewpoint Sensor (6112)

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
technical bulletin
When Control Link ACC controllers are networked
together via MODBUS, a single dewpoint sensor con-
nected to one Control Link ACC may be shared by
multiple Control Link ACC controllers.
Door Temperature Sensor (P/N 201-6008)
In addition to the indoor air dewpoint, the Control
Link ACC also factors in the value of the temperature
of the case door frame using an externally mounted
temperature sensor. This small thermistor mounts to
the coldest surface of the door frame.
The door temperature sensor is supplied with an
8-foot two-wire cable with Molex connector, which
plugs into the Control Link ACC.
Mounting the Control Link ACC
The Control Link ACC enclosure is
designed to be mounted in a case mul-
lion, but may also be mounted in the
raceway or in a metal electrical enclosure
on the top of the case. Figure 4 shows
examples of where the Control Link
ACC may be mounted.
Use the two mounting tabs at the top and
bottom of the enclosure to screw the
enclosure to the case wall, raceway, or
enclosure.
The tab at the top end of the Control Link ACC (the end nearest the CPC logo) must be securely
mounted against a large heat-conductive surface. This tab has a metal backing which acts as a
heat sink, dissipating heat from the Triac that controls the heater. The metal tab must be
mounted against a conductive metal surface of at least 64 square inches so heat can be con-
ducted out of the controller. Failure to secure the top tab against the case mullion may cause con-
troller overheating and shutdown.
Use 9/64” drill holes for mounting, and secure the Control Link ACC to the metal surface using
#8-32 thread trilobular thread forming screws, Taptite II or equivalent (Ref. Ty-Bolts
#SCHWSZ08043-TR). Mounting screws are not included with the Control Link ACC.
Figure 3 - Dewpoint Sensor (6111)
(Discontinued)
Figure 4 - Control Link ACC Mounting
ACC
ACC
ACC

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
technical bulletin
Wiring The Control Link ACC
Power And Heater Element Wiring
The four leads on the top end of the Control Link ACC
enclosure are where the connections to supply voltage
and the case door heater element(s) are made.
Connect the WHITE wire to the NEUTRAL side, and the
BLACK wire to the HOT side of 120-230VAC, 50/60Hz
line voltage.
The RED lead carries supply voltage when the door
heater Triac relay is ON (closed). Connect the RED and
WHITE leads to the case door heater elements. All
heater elements in the door frame and all doors of that
frame should be connected in parallel to the Control
Link ACC.
Connect the GREEN lead on the controller to ground.
Ratings and Current Protection
The Control Link ACC’s Triac is fused for 20A, 250V on the heater circuit, with a separate 1A
fuse on the control components so that communication can continue even if the Triac’s fuse
blows. Neither fuse is field-replaceable; if a fuse on the Control Link ACC blows, the controller
should be replaced. The maximum heater load is UL approved up to 13A.
WARNING! DO NOT CONNECT THE
POWER TO THE DEWPOINT SENSOR
LEADS AT THE BOTTOM OF THE ENCLO-
SURE. The small-gauge leads at the bottom
are the same colors, but they are for the dewpoint sen-
sor. Connecting power to these leads will damage the
board.
Figure 5 - Power/Heater Wiring
ACC

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
technical bulletin
Mounting and Wiring the Sensors
The Dewpoint Sensor
Placement
In order for the Control Link ACC to
function properly, the dewpoint sensor
must be placed where it can measure
the dewpoint of the air outside the
case. Mount the sensor underneath the
top side of the case in the area just
above the top of the doors (see
Figure 6). If the sensor cannot be
placed there, mount the sensor on top
of the case.
Do NOT mount the dewpoint sensor
near the bottom of the case or any
place where cold air from the case can
affect the sensor reading. Avoid
mounting the sensor in an area with
excessive water spray or moisture, extremely dirty environments, near heat sources, or in the
direct path of HVAC returns.
Note About Using RTV Sealants
Placing the dewpoint sensor in either of these locations may require a hole to be drilled in the case
to run the wire from the sensor to the Control Link ACC. Use caution when sealing this hole with
RTV sealants — the sensor element is sensitive to high concentrations of RTV. Do not let any
RTV sealants touch the sensor element, and keep the sensor element as far as possible from where
the hole is sealed.
Dewpoint Sensor Mounting Dimensions
The Dewpoint Sensor is provided with a pair of
mounting holes with 2.75” spacing. Choose a
location as close to the case doors as possible,
preferably directly over the doors or (if necessary)
on top of the case. Secure the sensor to the mount-
ing location with two screws (not supplied —rec-
ommended size #6 x ¼” long with sheet metal
threads). Hex head is recommended, but a slotted
head can be used. Note that the enclosure allows
clearance for a nut driver on the screw head.
Figure 7 shows the mounting dimensions.
Figure 6 - Sensor Placement
Figure 7 - Dewpoint Sensor Dimensions

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
technical bulletin
It may be necessary to cut a 0.25”x0.25” notch in the edge of the metal frame behind the sensor
for the wires to pass through.
Dewpoint Sensor Wiring
For wiring, the Dewpoint Sensor is pro-
vided with a 12-foot cable with a four-wire
pigtail at the end (P/N 335-3200). Connect
the cable to the dewpoint sensor leads at the
bottom of the Control Link ACC enclo-
sure, matching wire colors as shown in
Figure 8. Retail Solutions strongly recom-
mends Dolphin Super B Wire Connectors
(P/N 110-1000) for all crimp connections.
If the Control Link ACC will not have a
dewpoint sensor connected to it, it is recommended you insulate the ends of the Control Link
ACC’s dewpoint sensor leads by capping them with Dolphin Super B Wire Connectors.
Dewpoint Sensor Storage
Prior to installation, dewpoint sensors should be stored separately from the cables. Do not store
cables and sensors together for a long period of time in a closed box or bag. The sensor should be
separated from the cables when a shipment is received and stored apart, preferably exposed to
room air. The sensors can become contaminated by outgassing from the cable insulation if kept in
a closed up box or bag with the cable. Contamination can be reversed with exposure to room air
over a period of weeks or in a temperature/humidity chamber over a period of three days.
The Door Temperature Sensor
Placement
The Door Temperature Sensor should be placed in an area where it can measure the temperature
of the door frame in the location on the door frame that stays the coldest. The coldest spot on a
door frame is usually the bottom horizontal section of the stationary frame, under the center door
(for cases with even-numbered doors), or near the center mullion (for cases with odd-numbered
doors). Cooler doors may also be coldest at the top center of the frame. Figure 6 on page 4 shows
an example of placement in a case with even-numbered doors — the sensor is placed under the
door just to the left of the center mullion where the Control Link ACC is installed. Do not mount
the sensor inside the case mullion or anywhere outside the case.
Mount the case door temperature sensor along the door frame inside the frame. Secure the sensor
in place by screwing it to the door frame using the mounting hole.
NOTE: To replace the dewpoint sensor for recalibration pur-
poses, replace the entire assembly (keep the existing cable).
Figure 8 - Dewpoint Sensor Wiring
ACC

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
technical bulletin
The sensor is supplied with an 8-foot cable, with a Molex connector. Plug the connector into the
matching socket at the bottom of the Control Link ACC enclosure.
Network Wiring and Configuration
If each Control Link ACC will be configured with its own dewpoint sensor, it is not necessary to
network the Control Link ACC together. However, when networked, multiple Control Link ACC
controllers may use a single dewpoint sensor. Furthermore, because the Control Link ACC is a
MODBUS-compliant device, a site controller can be programmed to communicate with the Con-
trol Link ACC controllers via MODBUS, supporting remote configuration and data acquisition.
The E2 controller supports networking of up to 63 Control Link ACC controllers.
Network Connection to E2
Connecting a Control Link ACC to an
E2 unit requires the E2 to be version
2.71 or above. Contact Retail Solutions
for upgrade information if the controller
is a version before 2.71.
An E2 has up to three COM ports that
can be assigned for MODBUS commu-
nication (COM2, an RS485 port on the
E2 power interface board, and COM4
and COM6, which are optional ports
requiring expansion cards). COM ports
can only be used for one function; in
other words, if COM2 is set up as the
I/O network, you cannot connect MOD-
BUS devices to COM2. Ensure your E2
is equipped with an RS485 COM Card
(P/N 637-4890) and configured in E2
General Services (I, Serial
tab) to enable COM4 or an E2 Expansion COM Card (P/N 637-4871) to enable COM6.
Connect the MODBUS network cable to the three-terminal connector on the COM port you wish
to assign as MODBUS. Like other Control Link connections, wire RS485+ to RS485+, RS485- to
RS485-, and the shield cable to the middle terminal. If the E2 will be the first device in the daisy-
chain, set the port’s termination jumpers to the TERMINATED & BIASED position (all three
jumpers UP); otherwise, set all jumpers DOWN if not the first device.
COM1
COM4
COM6
COM2
Serial Device
RS485 COM Port
(2 Connectors)
RS485 COM Card
(2 Connectors) Serial Device
RS232 Port
POWER INTERFACE BOARD
(PIB)
E2 Modem/Expansion
COM Card Mounted
Above PIB
Plug-In
Modem
Card
COM3
E2 Enclosure (Right Side)
RS485
RS232
Figure 9 - Location of E2 COM Ports

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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E2 Setup of Control Link ACC Devices
Set Up Network Ports
Before setting up a Control Link ACC, the port on the E2 that has the MODBUS cable connected
must be set up as a MODBUS port.
1. Log in to the E2 with Level 4 access.
2. Press I followed by  - General Controller Info.
3. Press 4+ to open the Serial tab of the General Controller Info setup screens:
4. This screen will have a “Connection” field for all COM ports on the E2. Highlight the COM
port connection field that will be used for Control Link, and press D - LOOK UP. From
the list of network types, select MODBUS.
5. Four fields will become visible underneath the COM port connection field, which pertain to
the way the device communicates:
•Baud - Default setting is 19.2k. The baud rate setting should be set to match the baud rate dip switch settings
of all Control Link devices. (All devices connected to the same COM port should be set to the same baud
rate.)
•Data Size - Leave this field at the default value (8).
•Parity - Leave this field at the default value (None).
•Stop Bits - Leave this field at the default value (1).
6. Press J to save changes and exit.
Add and Connect Control ACCs
To enable communications between E2 and the Control Link units, the devices must be added and
addressed in E2.
1. Log in to the E2 with Level 4 access.
2. Press I - Connected I/O Boards and Controllers.
Figure 10 - Serial Communications Manager Screen

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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3. In the Connected I/O screen, in a box labeled ECT Devices. Enter the number of ACC devices in the
CtrlLink ACC number field.
4. Press J to return to the Network Setup menu, then select  - Controller Setup.
5. Locate the CtrlLink ACC units you added to the network list (press 8 and 7 to scroll through the list). The
default name for a Control Link ACC begins with a two-letter designator of the model type (AC for anti-con-
densate). If desired, enter a new name for each device in the Name field.
6. By default, each CtrlLink ACC in the network list has a board number of 0. To set the address and begin
communication, press D and select  - Select Address. In the list of MODBUS devices, choose the
address number corresponding to the Control Links ACC’s dip switch/jumper setting, and press > to
select it. If a network ID has already been selected, its name will be shown next to the network ID in this list.
If the network ID you are trying to assign has already been used, you must set the network ID dip switch/
jumper on this device to a different number that is not being used.
Figure 11 - Connected I/O Screen
Figure 12 - Controller Setup Screen

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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7. Repeat Steps 5 and 6 until each Control Link ACC device has a name and address.
8. When finished, press J to return to the Network Setup menu, then press  - Online Status (Figure 14).
Locate the Control Link ACCs you set up, and look at each device’s status in the Status field. You will see
one of the following messages:
•Online - The Control Link ACC is communicating normally.
•Offline - The Control Link ACC is not communicating, has not been commissioned, is not functional, or is not powered up. Ver-
ify the Control Link ACC is powered up, wired correctly, and has the proper network address, baud rate, and parity (see
“Troubleshooting Control Link ACCs and the ECT MODBUS Network” on page 18).
•Unknown - The Control Link ACC is not communicating or has not been commissioned. Verify the Control Link ACC is pow-
ered up, wired correctly, and has the proper network address, baud rate, and parity (see “Troubleshooting Control Link
ACCs and the ECT MODBUS Network” on page 18).
•No Port - No port is set up in the E2 Serial Configuration Manager to be a MODBUS port. Follow the instructions in “Set Up
Network Ports,” page 7.
•Wrong FW Rev - This message is likely caused by the Control Link ACC having a firmware version older than the minimum
revision required by E2 for communication. Replace the Control Link ACC with a new controller that has the latest version
of firmware on it.
Figure 13 - List of MODBUS Devices

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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Wiring Types
Retail Solutions specifies Belden #8761 shielded twisted pair cables for use as MODBUS wiring (or Belden
#82761 and Belden #88761 for plenum installations).
If the recommended cable is not available in your area, be sure the wiring meets or exceeds the following specs:
Shielded? Yes
Conductor Type Twisted Pair
Gauge 18 - 24 AWG
Capacitance between
signal wires 31 pF/ft or less
Capacitance between
signal and shield 59 pF/ft or less
Maximum Length 4000 ft/18 to 22 AWG
2500 ft/24 AWG
Nominal Impedance 120Ω±50Ω
Figure 14 - Online Status Screen

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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MODBUS Networks and Daisy-Chaining
Control Link ACC must be networked in a single open communi-
cations loop, or daisy chain. A daisy chain connects all the Con-
trol Link ACCs together in a single unbranched series, and
requires termination jumpers to be set on the controllers at either
end of the chain. No branching or “star configurations” are
allowed.
Step 1: Open the Control Link ACC Enclosure
Connecting a Control Link ACC to a MODBUS network
requires you to remove the top cover from the Control Link ACC
enclosure. Press down the tab at the top end (power wiring side) of the enclosure, and remove front cover of the
Control Link ACC. If the Control Link ACC is already mounted in the case mullion, you may have difficulty
removing the front cover; if so, loosen the top mounting screw before pressing the tab.
Step 2: Connect the MODBUS Network Cable
MODBUS network cable has two conductors plus a shield.
For each Control Link ACC, connect the two conductors to
the 485+ and 485- terminals of the MODBUS connector (at
the bottom of the enclosure), making sure to use the same
wire colors for each Control Link ACC connection. For
example, if the conductor wire colors are BLACK and
WHITE, use BLACK for all 485+ terminals and WHITE for
all 485- terminals (or vice-versa). Connect the bare
(SHIELD) wire to the center (0V) terminal.
Step 3: Set the Network Address
NOTE: If you are networking Control Link ACC only for purposes of sharing a dewpoint sensor, you do not need
to set a network address. Set all network address dip switches or jumpers to the DOWN (OFF) position.This
will allow the Control Link ACC to share a dewpoint sensor as long as the network is physically present and ter-
minated correctly. The network address is only necessary for assigning a network ID for MODBUS applications.
Depending on the hardware revision, the Control Link ACC board has either eight dip switches or eight three-pin
jumpers, located in between the controller and network status LEDs. Switches or jumpers 1-6 set the network ID
for the controller. Switches 7 and 8 set the network baud rate and parity.
Each Control Link ACC that will use the MODBUS network must have a unique network ID. Number each con-
troller in sequence, starting with 1. Refer to Figure 17 for dip switch and jumper settings.
WARNING! Disconnect the supply power
from the Control Link ACCbeforeopeningthe
enclosure. Opening the enclosure while the
Control Link ACC is powered may result in
electrocution.
Figure 15 - Control Link ACC Daisy Chain
ACC
Figure 16 - Control Link ACC Network Connection
ACC

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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Step 4: Set the Network Baud Rate and MODBUS Parity
NOTE: If you are networking Control Link ACC only for purposes of sharing a dewpoint sensor, you do not need
to set a baud rate or parity. Set all dip switches or jumpers to the DOWN (OFF) position.This will allow the
Control Link ACC to share a dewpoint sensor as long as the network is physically present and terminated cor-
rectly. The dip switches or jumpers are only necessary for assigning a network ID for MODBUS applications.
In order for the Control Link ACC to communicate with each other on the MODBUS network, they must all be
set to communicate at the same baud rate and parity.
Switch/jumper 7 determines the baud rate at which the controllers communicate. When switch/jumper 7 is ON,
the Control Link ACC will operate at 9600 baud. If switch/jumper 7 is OFF (default), the Control Link ACC will
operate at 19200 baud. Switch/jumper 8 determines the MODBUS network parity. Some MODBUS-enabled site
controllers require even network parity; to enable even parity, set switch/jumper 8 to the ON position. For site
controllers that require no parity, set switch/jumper 8 to the OFF (default) position.
Figure 17 - Control Link ACC Network ID Dip Switch/Jumper Settings
ACC
ACC
ACCs
Figure 18 - Control Link ACC Network Baud Rate/Parity Dip Switch/Jumper
ACC
ACC

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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Step 5 - Terminate the End Devices
Once all Control Link ACCs are networked, you must terminate
the end devices on the network. The Control Link ACC controller
board has a set of three jumpers at the bottom right corner of the
board that may be used to provide termination resistance.
To terminate an end device, set all three jumpers to the UP posi-
tion (jumper across the top and center pins). All other devices
that are not at the ends of the network must be unterminated. Ver-
ify that all devices that are not on the end of the network have all
three jumpers set to the DOWN position (jumper across the cen-
ter and bottom pins).
Step 6 - Connect a Dewpoint Sensor to Control Link ACC(s)
on the Network
Once the Control Link ACCs are networked and properly termi-
nated, the only step remaining to allow the Control Link ACCs to
share a dewpoint sensor is to connect at least one dewpoint sensor to one Control Link ACC on the network. Any
Control Link ACC on the network can be configured with the dewpoint sensor.
Each Control Link ACC first looks for a dewpoint sensor connected to itself. If a dewpoint sensor is directly con-
nected to a Control Link ACC, it will use that sensor for its dewpoint value and broadcast the sensor’s value on
the MODBUS network. If no sensor is directly connected to a Control Link ACC, it will automatically look on
the MODBUS network and use the sensor value broadcast by another Control Link ACC that has a sensor.
For fail-safe purposes, you may have multiple dewpoint sensors connected to different Control Link ACCs on
the network. The Control Link ACCs automatically select a primary sensor to use, and will switch to another
dewpoint sensor on the network if the primary sensor fails or is disconnected.
For dewpoint sensor wiring instructions, refer to Figure 8 on page 5.
Figure 19 - Control Link ACC Network
Termination
ACC

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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Step 7 - Set the Setpoint Temperature Offset
Jumper(s)
The Control Link ACC seeks to maintain a constant
minimum difference between the dewpoint of the
outside air and the temperature of the door frame.
You may specify how big this difference will be by
setting the temperature offset jumpers on the dew-
point sensor or the Control Link ACC board.
The offset jumper on the dewpoint sensor is located
on the circuit board on the underside of the sensor
enclosure (use needle-nose pliers to reach the
jumper). The offset jumper on the Control Link
ACC is located on the bottom end of the controller
board near the dip switches (see Figure 20).
The offset jumpers determine the number of degrees
(in Celsius) that will be added to the value of the
dewpoint sensor to determine the target temperature
of the door frame. For example, if the current dew-
point is 5°C and the jumpers are set to a medium
offset of 2°C, the Control Link ACC will control the
heaters to achieve a door frame temperature of 7°C.
As the dewpoint rises and falls, the door frame temperature setpoint will also rise and fall, so that the door frame
temperature will always stay slightly above the current dewpoint.
The Control Link ACC uses jumpers on both the
dewpoint sensor and the Control Link ACC board
itself to determine the value of the temperature off-
set. The Control Link ACC prioritizes them in the
following ways:
•The dewpoint sensor’s temperature offset jumper takes
priority over all Control Link ACCs. The setting of
the dewpoint sensor’s jumper is used by all Control
Link ACCs on the network that are using that sen-
sor for its dewpoint provider.
•If the dewpoint sensor’s temperature offset jumper is
removed, all Control Link ACCs will use the tem-
perature offset specified by each Control Link
ACC’s own temperature offset jumper.
This priority structure is designed to make it easier
for temperature offsets to be changed in the field (by
Figure 20 - Setpoint Jumper Location and Settings
HML
HML
HML
OFFSET JUMPERS
ACC
OFFSET JUMPERS
DEWPOINT SENSOR
OFFSET JUMPERS
ACC
DEWPOINT
DISCONTI
N
U
E
D
Figure 21 - Setpoint Jumper Location and Settings
(Discontinued)

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
technical bulletin
simply changing it on the dewpoint sensor), and it also allows multiple cases to use the same sensor while using
different temperature offsets.
When setting up Control Link ACCs and temperature offset jumpers, choose either a HIGH offset (4 degrees C),
a MEDIUM offset (2 degrees C) or a LOW offset (0 degrees C) and set each Control Link ACC and the dewpoint
sensor to the required position for the chosen offset.
Step 8 - Replace the Control Link ACC Enclosure Covers and Restore Power
Network configuration is complete. Replace the enclosure cover by pressing it against the enclosure until it snaps
into place. Restore power to the Control Link ACC. Check the status of the network by observing the LEDs on
the front of each Control Link ACC enclosure:
•If network communication is active, you should see the Rx LEDs blinking about once every 15 seconds. If you see no activity or
a regular blinking pattern, there may be a problem with the MODBUS network wiring or configuration.
•For Control Link ACCs equipped with dewpoint sensors, you should see the Tx LED blink to indicate transmission. If not, there
may be a problem with MODBUS or dewpoint sensor wiring.
•For Control Link ACCs that do not have dewpoint sensors directly connected to them, verify the STATUS LED is blinking once
every 2 seconds to indicate status is OK. If this LED blinks in a repeating pattern of three short blinks, it means the Control
Link ACC is not receiving a dewpoint sensor value broadcast over the network. There may be a problem with the MODBUS
or dewpoint sensor wiring.
Operation
Control Link ACC Status LEDs
The Control Link ACC has four status LEDs that indicate what the controller is
doing. They are: the Heater Status LED (HEAT), the General Status LED (Status)
and the two Network Status LEDs (Tx and Rx).
Heater Status LED
The Heater Status LED (HEAT) glows red any time the door heaters are ON, and
is OFF when the heaters are OFF.
Under normal operation, this LED should pulse ON and OFF when no door sweat
is visible, indicating it is pulsing the heaters to maintain the necessary amount of
heat to prevent door sweating (given the current dewpoint and case temperature).
When a case door is opened, the LED will remain ON for longer periods of time
(and may even remain ON without pulsing) to compensate for the change in case
door temperature.
Note that it is possible for this LED to remain OFF for long periods of time if the dewpoint is very low (e.g., dur-
ing dry winter days).
TIP: Experiment with offsets to find the lowest possible setting that still offers good
performance. In many cases, depending on the placement of the door frame tempera-
ture sensor, a LOW offset will still provide good anti-condensate performance. The
lower the offset being used, the higher the energy savings.
Figure 22 - LED Locations

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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General Status LED
The General Status LED (STATUS) blinks green to indicate the controller is powered up and functioning nor-
mally, and whether or not there are any alarm conditions.
If the controller is functioning normally, the STATUS LED will blink once every two seconds. If there is an error
condition, it will blink at different rates to indicate the active error condition (see the Error Modes section
below).
Tx and RX Status LEDs
If the Control Link ACC is being networked with other Control Link ACCs via its MODBUS network connec-
tion, the Tx and Rx LEDs blink to indicate transmission and receipt of network messages. On a properly net-
worked Control Link ACC, the Rx LED should blink about once every 15 seconds. If a Control Link ACC has a
dewpoint sensor, you should also see the Tx LED blink. If these LEDs do not blink, there may be a problem with
the MODBUS network connection.
Error Modes
The Control Link ACC has several error modes it will enter when failures occur. If any of the error modes below
occur, the green STATUS LED will blink at a rate specific to the error condition. For each error mode, note the
priority level — if more than one error mode is active, the LED blink rate will only show the error condition with
the highest priority (priority #1 is the highest, and priority #5 is the lowest).
Priority 1: FAIL THERMAL SHUTDOWN
The Control Link ACC has an internal temperature sensor that will turn OFF the heater if the Triac driving the
heater exceeds a temperature above 105°C. During thermal shutdown the STATUS LED will blink 5 times,
pause, and repeat. Thermal shutdown will automatically clear itself when the Triac internal temperature falls
below 102°C.
If a Control Link ACC experiences a large number of thermal shutdowns, there may be a problem with heat sink-
ing on the Control Link ACC. Make sure the metal tab on the back of the Control Link ACC is mounted securely
against the metal in the mullion for proper heat conduction.
Priority 2: TEMP SENSOR FAILURE
This error occurs when the Control Link ACC is not receiving a valid temperature value from the door tempera-
ture sensor. When this condition occurs, the Control Link ACC will revert to an open loop control method com-
monly used in E2 & PMAC. While operating in this mode, the Control Link ACC will be controlled according to
the dewpoint within the store.
Dewpoint Output
65°F (18°C) 100%
55°F (12.8°C) 75%
45°F (7.2°C) 50%
35°F (1.7°C) 25%
25°F (-3.9°C) 0%

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
technical bulletin
The “Full ON” and “Full OFF” values (65°F and 25°F respectively) can be adjusted via HHT connected through
the MODBUS system.
When the temp sensor has failed, the STATUS LED will blink twice, pause, and repeat.
Note that it is possible to select the PMAC-style mode of operation without the Control Link ACC generating an
alarm. PMAC mode may only be enabled using a HHT connected through a Retail Solutions gateway.
Priority 3: DEWPOINT SENSOR FAILURE
This error occurs when the Control Link ACC is not receiving a dewpoint sensor value (either from a dewpoint
sensor directly connected to the Control Link ACC or from another sensor on the network). The Control Link
ACC will continue controlling the heater with a fallback door temperature setpoint of 59°F (15°C) until the dew-
point sensor connection is restored.
When the dewpoint sensor has failed and/or the Control Link ACC cannot find a dewpoint sensor value on the
network, the STATUS LED will blink three times, pause, and repeat.
Priority 4: FLASH/CLOCK FAILURE
A firmware or hardware error has occurred, and the Control Link ACC is unable to function. A controller in this
error state will require replacement. The STATUS LED will give one short blink, one long blink, pause, and
repeat the pattern.
Priority 5: USER CONFIG LOST
The user configuration has been corrupted. All setpoint changes have been reset to the original factory defaults.
The STATUS LED will give one long blink, one short blink, pause, and repeat the pattern.

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Installation Instructions: Control Link ACC Anti-Condensate Controller System
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Specifications
Troubleshooting Control Link ACCs and the ECT MODBUS Network
Problem: Control Link ACC Offline
1. Check wiring - Verify the Control Link ACC is properly connected to the MODBUS cable. Verify the net-
work polarity is correct (+ to +, - to -, 0V to 0V) and there are no loose wires. If none of the Control Link
ACCs are online, check wiring connections on the E2. Check the cable jackets to make sure all network cable
is Belden #8761 or equivalent.
2. Verify MODBUS Port Setup - Press 6++ on the E2 front panel. Verify COM2, COM4, or COM6 is set up
as a MODBUS port. If so, verify that the MODBUS cable is connected to the proper connectors (refer to Fig-
ure 9 on page 6). Verify the COM port fields are properly set for ECT MODBUS (19.2k baud, data size=8
bits, Parity=NONE, stop bits=1).
3. Make sure Control Link ACCs were commissioned - Press Ifollowed by  on the E2 front panel
and verify the offline Control Link module has a non-zero number in its Board# field. If the number in the
Board/Node field is zero, highlight the controller name and select D - SET ADDRESS followed by  -
Select Address. Then select the network ID that matches the setting on the network address DIP switch/
jumper.
4. Check Control Link ACC network card DIP switch/jumper settings - make sure switches/jumpers 1-6 on
the Control Link ACC network card match the network ID number of the offline Control Link ACC.
5. Verify switches/jumpers 7 and 8 are in the DOWN position - Switches/jumpers 7 and 8 in the DOWN posi-
tion specify 19.2k baud and no parity. If either of these switches/jumpers are not in the DOWN position, set
them DOWN.
6. Check network termination - The two devices on either end of the MODBUS network should be terminated,
with all other devices in the daisy chain unterminated. Check jumper settings for all devices on the network.
Ambient -40°C to +65°C
Humidity 5% to 95% non-condensing
Door Sensor +/- 0.4°C of 0 to 80°C; up to +/- 0.6°C at -40°C and 120°C
Dewpoint Sensor +/- 1°C over RH of 40 to 95% RH
+/- 4°C over RH of 10 to 40% RH
Input Voltage 102 to 265 VAC
UL Recognized File E110725
Table 1 - Control Link ACC Specifications