Parts And Service; Troubleshooting; Parts - Daikin MicroTech III Installation And Maintenance Manual

Troubleshooting

Follow these procedures if you are not able to communicate
with the chiller via the network:
General
→ Review the Installation and Mounting
document to confirm that all procedures were followed
correctly.
→ Review the Network Configuration
document to confirm that all procedures were followed
correctly.
→ If the Modbus communication module is installed but
LEDs are not active when the unit controller is powered
up, remove the module and then follow the steps
provided in the Installing a new Communication Module
section. If the issue persists, replace the module.
→ Verify that the Modbus Setup menu appears in the
unit controller keypad/display. If it does not, follow this
procedure:
1. Set the Unit On/Off Switch to "Off" from inside the
control panel of the unit.
2. Remove power from the unit controller, wait 10
seconds, then re-power the chiller unit controller.
Within 45 seconds, the unit controller should
recognize the attached Modbus communication
module, and will cycle power.
3. Verify that the Modbus Setup menu now appears in
the unit controller keypad/display.
Network Parameters
→ Verify that the network address of the Modbus
communication module (slave) is unique in the network.
In contrast, the baud rate, stop bit, and parity settings of
the communication module must match the other slave
devices on the network.
→ Make sure there are no duplicate devices on the
network and that network parameters are set correctly as
shown in Table 3.
→ View the Modbus communication module's BUS and
BSP LEDs. Refer to Table 1
of the communication status among the unit controller,
communication module, and the network based on the
LED activity.
IM 969-5 • MICROTECH III CHILLER UNIT CONTROLLER
section of this
section of this
and Table 2 for explanations
Network wiring
If performance is unsatisfactory or network is experiencing
issues such as noise or slow transmission:
→ Confirm that the shield is landed at only one point in
the trunk.
→ Be aware that the recommended network topology is
daisy-chain (no T-Taps or ring layout).
→ Verify that network wiring does not exceed 4000 ft
total distance limit (without repeaters) at 38400 bps
baud.
→ Verify that polarity is maintained.
→ Check that there are end-of-line termination resistors
(120 Ω) at the first and last device on the trunk. This is
required by the EIA-485 specification.
→ Verify that the network trunk avoids strong sources of
electromagnetic interference (EMI).
→ Note that the two-wire bus is not interchangeable and
must be connected correctly.
→ Verify that the network trunk is not located near a DC
load switch (relay).
Network Performance
→ If network traffic is slow, communication is intermittent,
or the trunk is experiencing "noise," it may be necessary
to use a network protocol analyzer or oscilloscope to
determine the source of poor performance.
→ Confirm power is applied to the unit controller.
Contact the Daikin Applied Controls Customer Support group
at 866-462-7829 for additional assistance, if necessary.

Parts

Table 4: Replacement Parts List
Description
MicroTech III Modbus communication module kit
Kit includes: Modbus communication module, board-to-
board connector, network connector, and IM 969
Network connector (3-pin)
Board-to-board connector (10-pin)
To find your local parts office, visit
call 800-37PARTS (800-377-2787
12
P s
arTs and ervICe
P s
arTs and ervICe
Part Number
350147413
193410303
300047027
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