Daikin Sky Air FAA71BUV1B Service Manual page 84

5 | Third party components
Service manual
84
Is the wiring correctly executed, as
indicated in the installation manual?
Yes
No
To measure the F1-F2 transmission
F1-F2 transmission is a D3Net rectangular waveform, 16 VDC ± 5 V with 16-5V
amplitude that appears on the 16V base line:
5 V
16 V
F1-F2 terminals on indoor units, outdoor units and central controllers are all
possible measurement points. Use as many points as you can and take the time
necessary for measurement if analyzing with an oscilloscope.
On outdoor units, measurement should be done either at F1-F2 IN or F1-F2 OUT. If
the F1-F2 OUT terminal is not used, then measure at the F1-F2 IN terminal.
You can conduct the measuring with a multimeter or an oscilloscope.
To measure the F1-F2 transmission with a multimeter:
4 Set the multimeter to DC Voltage measurement.
5 Measure on the F1 and F2 terminals.
Result: 16 V DC should be read.
To measure the F1-F2 transmission with an oscilloscope:
INFORMATION
Ensure that probes are securely connected to F1-F2 terminals. Otherwise, distortions
will be generated resulting in misinterpretation of data. It is recommended to
connect temporary cables to the probes and then connect the cables to the
terminals securely.
6 Measure at as many points as you can, this can help to determinate the
problem.
For example: if the measurements at the indoor unit side are distorted while
central controller and outdoor unit seem OK, you can suppose that the failure in
transmission is related to the indoor unit side.
7 Set time base (horizontal) to 50 µs/div to 100 µs. Voltage axis (vertical) should
be set to 2V/div to 5V. Set position properly, otherwise the data may appear
outside the screen. In AC mode, which is a sampling mode in oscilloscopes,
waveforms appear in the middle of the screen. So, it is recommended to use
AC mode if possible.
8 Set the triggering mode of the oscilloscope to "Normal". If "Auto" mode is
selected, observed waveforms may be cleared instantaneously leading to
misinterpretation of data.
9 Ignore very short-time pulses of 1V amplitude or less, or overshooting at the
rising edge may be ignored. Focus on the shown points of the waveform
below:
Action
Continue with the next step in this
checking procedure.
Modify the wiring, see the installation
manual.
FAA71+100BUV1B
Sky Air indoor units
ESIE22-01 – 2022.02