Procom VOR/ILS Analyzer EVS200 - Manual (Page 50)

VOR/ILS Analyzer EVS200
0796.1800.02 E-8 41
Chapter 3: Operation
Command FA3
command function
FA3 <Fast DDM measuring on> Activating the Fast DDM measurement
The command FA3 switches on the fast DDM measurement. The measuring, used only for landing
path measurement can only be activated through a controller. The command FA3 performs the con-
tinuous measurement and output of the DDM, RF level, Modfactor 90 Hz and Modfactor 150 Hz.
The 50-ms measurement interval consists of DSP analysis, DSP data transmission to the host
processor and conversion of the DSP raw measurement value into DDM, dBm and AM %. The
measurement values output is performed in this mode as interrupt operation via RS232 interface.
In this Fast-Mode (FA3) a measurement value set will only be transmitted to the PC if it is demanded
by a short command (1 ASCII-Character). The response from the EVS200 is performed without a
longer delay within about 15 to 20 ms between measurement value demand and measurement
value transmission. The stated RS-232-transmission times are related to 19.200 Baud.
The measurement values can be read in and output as a text file corresponding to the terminal pro-
gram.
The baud rate must be set to 19200 baud in the Setup of the VOR/ILS Analyzer
EVS200. It must be attended the acceptance of the data transfering rate by the
terminal program.
The measurement can be stopped through the command FA0 (refer to Command
FA0) or
<CR>.
Example:
command from the controller response of the VOR/ILS Analyzer EVS200
input: e.g. A
Demand for measurement
values output:
all ASCII characters without:
CR (0Dh), LF (0Ah), # (23h), @ (40h)
With the command FA3 the echo
mode is automatically switched
OFF.
output form: (DDM <CR >, RF level <CR >,
AM90 <CR >, AM 150 <CR >)
output form as FA2
example: -0001 <CR > (DDM),
-412 <CR > (RF level),
201 <CR > (AM90),
202 <CR > (AM150),
DDM, AM90, AM150,
RF-Level - Calculation
1/90Hz = 11.1msec.
DSP-Analysis
DATA-Transfer
DDM, AM90, AM150,
RF-Level - Calculation
RS232-
Transfer
Answer to PCl
fromEVS200 (TXD
15...20 msec.
10 msec.
N N+1 N+2 N+3 N+4 N+5 N+6 N+7 N+8 N+9 N+10
N
DATA-Transfer
DDM, AM90, AM150,
RF-Level - Calculation
DATA-Transfer
Request from PCl
to EVS200 (RXD)
Programm-Interrupt