Ma Remote Controller Transmission - Mitsubishi CITY MULTI PUD-P250YMF-C Service Handbook

4Indoor Unit Control Transmission shield line is
grounded at the outdoor unit
5Check the shield for transmission line
(for centralized control)
2When transmission wave height is low. When 6607 error code is displayed or while "HO" is displayed the
remote controller.
6The distance between outdoor/heat-source unit and
farthest indoor unit exceeds 200m
7Transmission wire other than the one specified is
used
8Choke coil of transmission power-supply circuit is
damaged
9Malfunctioning indoor unit

[2] MA Remote Controller Transmission

MA remote controller and indoor units communicate with each other by using electrical current tone burst
method.
(1) Effects of noise in transmission line
When noise enters transmission line and normal communication between MA remote controller and indoor
unit cannot be made for three minutes, MA communication error (6831) will be displayed.
(2) Transmission/Wave Pattern Check
A1
B2
MA remote controller
Transmission wave patterns (Terminal Number 1-2)
logical
value1
12msec
Check Points
Check Points
TB15
Indoor unit
logical logical logical
value0 value1 value1
12msec 12msec 12msec
- 100 -
Use one-point grounding at outdoor unit. When not ground-
ed, transmission signals may be changed by trapped noise
and interfere with the communication.
For the shield earth of the transmission line for centralized
control, the effects of noise can be minimized if grounded at
the centralized control. However, transmission line for cen-
tralized control may be affected in various ways depending
on the transmission line length, number of connected units,
types of connected controller, or installation condition.
Check the following installation conditions:
a. No grounding
When using upper-rank controller ··· Provide grounding at
upper-rank controller (power-supply device)
b. When one-point grounding is provided but an error
occurred
··· Ground the shield at all outdoor units.
Make sure that the distance between outdoor/heat-source unit
and the farthest indoor unit is less than 200m.
Use specified transmission line.
1For systems using shield line
Type of transmission line - shield wire CVVS, CPEVS
2
Wire Diameter-over 1.25mm
Normal if the resistance of choke coil in the outdoor/heat-source
unit is between 0.5 and 2.6Ω.
Normal if resistance R3 of the outdoor main board is 1kΩ i5%.
When measuring resistance, disconnect connectors CNS1 and
CNS2.
Replace indoor controller board.
1
A1,B2:No Polarity
2
Between Terminals 1-2
··· Power Voltage (DC9~12V)
DC9~12V
1Must meet the standard 12msec/bit ± 5%
2Voltage of transmission number must be
within the range shown on the left.
Remedies
Remedies