IM 743-7 • MICROTECH II CHILLER UNIT CONTROLLER 8
www.DaikinApplied.com
Installation
Figure 9: Modbus Communication Module Cover
Replacing a Communication Module
Follow these steps to remove an existing communication
module from unit controller and replace it with a new one.
1. Remove power from the unit controller.
2. Locate the serial card slot on the unit controller
(
Figure 3
).
3. Pull the network cable connector from the
communication module.
4. Remove the cover from the serial card slot. Use a small
screwdriver to carefully pry it off from one end (
Figure 5
and
Figure 6
).
5. Grasp the communication module and carefully pull it
from the unit controller.
6. Install the new communication module. Grasp the
module, with the network connector on the underside.
The 8-pin header must mate to the 8-pin plug in the unit
controller. The plug has a guide on each end to direct
it into the mating guide on the communication module
header.
Figure 7
shows the serial card slot with the 8-pin
plug that mates to the header on the communication
module.
NOTE:
This operation relies more on fitting the
communication module into the connector than
seeing the connectors mate.
7. Insert the communication module, pointed up, into the
slot. Keeping it
level
, roll the module into position as
you guide it into the slot, feeling the connectors line up
(
Figure 8
, Steps 1 and 2).
8. When you feel the connectors align, press the
communication module into the connector. Verify that
the communication module is firmly connected (
Figure 8
,
Step 3).
9. Insert the plug-in connector to the communication
module.
10. Replace the cover on the serial card slot. Slip the cover
over the network connector plug (
Figure 9
).
11. Insert the network cable connector into the
communication module.
12. Connect the communication module to the network
(
Figure 10
and
Figure 11
):
a. Connect one wire of the network cable to Pin 2 of
the connector plug.
b. Connect the other wire to Pin 3 of the connector
plug. Note that no wire is connected to Pin 1
(GND).
Figure 10: Network Cable Routing and Connections
Figure 11: Network Connection Detail
Pin 2
Pin 3
RS-485
Network Cable
