FRSky, Version: 1.4
Page 12/16
8
Supported sensors
8.1
Telemetry Receiver D-series and S.Port Telemetry X-series
- announcement RX link quality in: % signal level + alarms
- announcement TX link quality in: % signal level + alarms
- announcement analog value 1 in: …
+ alarms
- announcement analog value 2 in: …
+ alarms (only D-series
8.1.1
analog inputs A1, A2 – "Volt ratio"
At the analog input A1 is usually the internal receiver-voltage
connected. To A2 another analog voltage can be connected and
brought to display.
The max. voltage for A2 as well as for A1 is 3.3 V.
To view larger voltages, voltage dividers must be used while
ensuring that the maximum possible voltage of the voltage
divider is a multiple of 3.3 V (i.e. only "integer" voltage
divider).
For example, from the "Instruction manual for FrSky Two-Way system" section 9.2.1 can be
seen that the internal voltage divider is designed for a max. battery voltage of 13.2 V, which is
exactly 4 times of 3.3 V. Thus, by a "Voltage ratio" for A1 the value of
4
is to be set (... for the
speech module VSpeak according to the table in section 5.3 no.11 & 12 ).
8.1.2
analog inputs A1, A2 – "Alarm Set"
For the analog inputs A1 and A2, two independent alarms can
be programmed:
A1_1 A1_2 and A2_1 A2_2
Setting the alarm level (0,1,2,3) and the comparison value ("<"
/ ">") is quite simple - a little more complicated is the
determination of the to be adjusted alarm value (Which alarm
threshold is set in the example at 100 and in the 8.1.1 predicted,
voltage ratio set = 4??).
To calculate the alarm values use the following two formulas:
1. Wanted: to be set alarm threshold
Given: Volt ratio, alarm value (inV)
2. Wanted: alarm value (in V)
Given: Volt ratio, set alarm threshold (in V)
Thus, with Formula 2 the above question will be answered with: 5.1 V
What alarm threshold was set for an alarm on receiver voltage <4.2 V at A1? With the help of
formula 1 (and Volt ratio = 4) is the result: 81
The alarm thresholds for the RX and TX are in turn easy, they are entered 1-1.
alarm value x 255
3.3 V x Volt ratio
to be set alarm threshold =
set alarm threshold x 3.3 V x Volt ratio
255
alarm value =
