Cooper&Hunter CH-IRT05NM, Service Manual, Page: 24 / 110

Rooftop Packaged Service Manual CONTROL
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When Lock function is turned on, any
other buttons won‟t respond when pressing. The function can be
memorized after power failure and then power recovery.
4.4 MEMORY FUNCTION
Press Mode and ▲ buttons at the same time for 5s under off state of the unit to turn on or cancel
memory function. If memory function is set, is displayed. If not, indoor unit is defaulted to be off
after power recovery.
If memory function is set, indoor unit will resume original setting state after power failure and then
power recovery.
Note:
If cut off power with 5s after memorized content is changed, the memorized content may be abnormal.
Do not cut off power within 5s after memorized content is changed.
4.5 MODBUS INTERFACE
The unit of this series has MODBUS interface. If the user needs to connect the unit to the
management system of the building, please enquire C
&H
for the MODBUS protocol.
Figure 2-4-2
(1) Interface instruction:
1) The printing is COM-BMS1 and the interface type is B4B-XH-K3;
2) Electrical characteristic: baud rate: 9600bps; standard: RS485;
3) Working principle:
The indoor mainboard can send out the unit operation state through this interface and receive logical
control information to realize control and monitor of the unit.
(2) Function instructions:
In order to achieve this function, set the address mode and address through wired controller. Please
refer to Point 3 for the setting method. You must set the address mode into long-distance control address
mode.