www.DaikinApplied.com 11 IM 743-7 • MICROTECH II CHILLER UNIT CONTROLLER
Follow these general procedures if you can control the
MicroTech II chiller unit controller from the keypad/display, but
are not able to communicate with the unit from the network:
General
→
properly (see Installation section).
Modbus using the keypad/display. Refer to the Network
section or the MicroTech II Chiller Unit
Controller OM (Reference Documents) for details.
Network Parameters
→ Verify that the Network Address of the communication
module (slave) is unique in the network. In contrast, the
Baud Rate must match the other slave devices on the
network.
→ Make sure there are no duplicate devices on the
network and that Network Address and Baud Rate are
set correctly as shown in Table 2.
If performance is unsatisfactory or network is experiencing
issues such as noise or slow transmission:
→
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 19200 bps
baud.
→ Verify that polarity is maintained.
→ Check that there are end-of-line termination resistors
→ 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
→
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.
→
Contact the Daikin Applied Controls Customer Support group
at 866-462-7829 for additional assistance, if necessary.
Parts
Table 3: Replacement Parts List
Description Part Number
MicroTech II Modbus Communication Module kit
Kit includes: Modbus communication module (RS-485
serial network board), network connector, and IM 743
350147402
Network connector
Wago 330803003
Phoenix (shown in Figure 12) 910108485
Figure 12: Phoenix Network Connector
www.DaikinApplied.com or
call 800-37PARTS (800-377-2787
To Next Page
Loading...
