Specifications

34
© 2012 Emerson Climate Technologies, Inc.
Printed in the U.S.A.
AE8-1368 R2
No Communication
Are termination jumpers properly set
(At compressor and at E2)? Is Parity
jumper “down” for use with E2? For E2
controllers, the Modbus jumper must be
set to “ECT”
Set termination
jumpers
“No Communication” will be shown on the ISD display. It
will be seen in the E2 detail status screen as the ISD
Display Code, and the Network Status will be “Offline”.
After 5 minutes of no communication, the control module
of the compressor will revert to the Failsafe run state.
This flow chart assumes that the initial commissioning
process has been completed to establish the node on the
network.
Does each compressor on the
network have a unique
address?
Unplug the RS485
connector(s) from
the network interface
board and check DC
voltage (left pin to
center, right pin to
center)
Set dipswitches for
correct node and
“reset” module
Look at amber LED on
the left side of the control
module RS485
connector
Are the amber or red
lights on all
compressors
continuously on?
2.3 to 2.6 volts
DC?
-Verify that the
shield connection
is made at the E2
RS485 connector
-Faulty interface
board in E2
Do you have one
transformer powering
more than one sensor
module?
With a common
transformer, left
side power
connector tabs to
use a common
supply leg, and
each right tab to
use a common
supply leg (see
schematic below)
Polarity of power connections for common transformer
Verify that there are no
unfiltered variable
frequency drives that are
generating excessive
electrical noise
Yes
Yes
No
Yes
No
Yes
No
• Verify polarity of the white/black
power supply leads going to the
control module. Refer to wiring
diagram in appendix. White
lead is by the connector latch at
the sensor module and goes to
control module pin #4.
• If electrical noise is suspected,
a communication noise filter
from “Fair-Rite Products Corp.
p/n 0431173551may be
installed on the communication
line. See figure 1.0. Three
passes through the filter are
recommended.
• Faulty control module
Sensor
Module
Sensor
Module
24 v
Figure 1.0
Fair-Rite Filter
Installed on RS-485
Communication Line
No
Correct the polarity
of wires at RS485
connector at E2
Yes
Is the amber light of this
compressor
continuously on?
No
Correct the polarity
of the wires at the
RS485 connector
on this compressor
Yes
No
Is there 2.3 to 2.6 volts
at the control module
RS485 connector?
Plug in the interface
board connector.
Measure voltage at the
control module
connector
Yes
Yes
Comm Wire Fault
No
The control module must be “on” and
the RS485 connector must be plugged
in to the control module and to the E2
controller (see E2 connection in photo
on the right)
6.14 a
Communication
Card and
Connector