Carrier 68RM35-610 Operation And Service page 29

3.3.1 Troubleshooting CAN Communication
NOTE
On the 12--00693--00 board the CAN commu-
nication line pins are on J4--PIN 14(CAN High,
CAN_H) and J4--PIN 15 (CAN Low, CAN_L).
The unit will continually broadcast messages.
Tools Required: RS232 adaptor, Voltmeter and
CAN USB adapter
Follow these steps:
1. Check CAN_H (J4--14) and CAN_L (J4--PIN15) is
connected to the bus CAN High and Low lines.
2. Check Bus CAN line has a shunt 250Ohm resistor.
3. Disconnect J4 connector and connect the RS232 ad-
apter.
4. Connect RS232 cable to CAN USB adaptor attached
to a laptop.
5. Open HyperTerminal by following "start\All
Programs\Accessories\Communications".
6. Select 'disconnect' and set communication settings
(Baud Rate 9600, Data Bits 8, Stop Bits 1, No Parity)
by following 'File Properties'.
7. Select 'connect'.
8. Enable CAN communication by sending the following
commands:
8a. 'S5' then 'enter key'
8b. 'O' then 'enter key'
9. Check board is transmitting. A continual stream of
text like given below should display.
T18FFE1198F1FFFFF4FFFF03FF
10.If there is no stream of text, STOP. The CAN chip is
not functioning.
11.Check the Board receives and responds to com-
mands by sending the following command to turn the
AC OFF.
T18EF1921800FFFFFFFFFFFFFF
Then 'enter key' and wait at least 1 minute for re-
sponse.
12.If the AC does not shut down then go to step 14.
13.Send the following command to turn the AC ON.
T18EF1921840FFFFFFFFFFFFFF
Then 'enter key' and wait at least 1 minute for re-
sponse.
T--356
14. Send the following command to set Fan Speed to
Low.
T18EF19218FDFFFFFFFFFFFFFF
Then 'enter key' and wait at least 1 minute for re-
sponse.
15.If there is no response, STOP. The CAN chip is not
functioning.
3.3.2 CAN Communication Command List
1. HVAC Main Switch ON:
T18EF192187FFFFFFFFFFFFFFF
2. HVAC Main Switch OFF:
T18EF192183FFFFFFFFFFFFFFF
3. Low Fan Speed ON:
T18EF19218FDFFFFFFFFFFFFFF
4. Low Fan Speed OFF:
T18EF19218FCFFFFFFFFFFFFFF
5. Vent:
T18EF19218FF0FFFFFFFFFFFFF
6. Heat:
T18EF19218FF1FFFFFFFFFFFFF
7. Cool:
T18EF19218FF2FFFFFFFFFFFFF
8. Auto:
T18EF19218FF5FFFFFFFFFFFFF
9. Set Point (75 F):
T18EF19218FFFF40FFFFFFFFFF
10.Boost Pump OFF:
T18EF19218F3FFFFFFFFFFFFFF
11. Boost Pump ON:
T18EF19218F7FFFFFFFFFFFFFF
3--2
03/11