[
IX
Troubleshooting ]
- 204 -
HWE1113B
GB
[3] Investigation of Transmission Wave Shape/Noise
1. M-NET
transmission
Control is performed by exchanging signals between the outdoor unit and the indoor unit (ME remote controller) through M-
NET transmission. Noise interference on the transmission line will interrupt the normal transmission, leading to erroneous op-
eration.
(1) Symptoms caused by noise interference on the transmission line
(2) Wave shape check
Wave shape check
Check the wave pattern of the transmission line with an oscilloscope. The following conditions must be met.
1) Small wave pattern (noise) must not exist on the transmission signal. (Minute noise (approximately 1V) can be generated by
DC-DC converter or the inverter operation; however, such noise is not a problem when the shield of the transmission line is
grounded.)
2) The sectional voltage level of transmission signal should be as follows.
Cause
Erroneous operation
Error code
Error code definition
Noise interference on
the transmission line
Signal is transformed and will be misjudged as the
signal of another address.
6600
Address overlap
Transmission wave pattern is transformed due to
the noise creating a new signal
6602
Transmission pro-
cessor hardware er-
ror
Transmission wave pattern is transformed due to
the noise, and will not be received normally leading
to no acknowledgement (ACK).
6607
No ACK error
Transmission cannot be performed due to the fine
noise.
6603
Transmission line
bus busy error
Transmission is successful; however, the acknowl-
edgement (ACK) or the response cannot be re-
ceived normally due to the noise.
6607
6608
No ACK error
No response error
Logic
Voltage level of the transmission line
0
V
HL
= 2.5V or higher
1
V
BN
= 1.3V or below
[With transmission]
[Without transmission]
No fine noise allowed
No fine noise
allowed
52
52
52
52
52
V
BN
V
HL
Logic "0"
Logic "1"
Summary of Contents for City Multi CMB-WP108V-G
Page 1: ...AIR CONDITIONER 2014 Service Handbook PURY WP200 WP250YJM A CMB WP108V G Model 3rd edition ...
Page 11: ... 2 HWE1113B GB ...
Page 27: ... I Read Before Servicing 18 HWE1113B GB ...
Page 29: ... 20 HWE1113B GB ...
Page 57: ... 48 HWE1113B GB ...
Page 70: ... III Outdoor Unit Components 61 HWE1113B GB 2 Power supply circuit board ...
Page 71: ... III Outdoor Unit Components 62 HWE1113B GB ...
Page 73: ... 64 HWE1113B GB ...
Page 81: ... IV Remote Controller 72 HWE1113B GB ...
Page 83: ... 74 HWE1113B GB ...
Page 89: ... 80 HWE1113B GB ...
Page 97: ... 88 HWE1113B GB ...
Page 127: ... 118 HWE1113B GB ...
Page 135: ... VIII Test Run Mode 126 HWE1113B GB ...
Page 137: ... 128 HWE1113B GB ...
Page 253: ... 244 HWE1113B GB ...