Acknowledge Detector Variant 2
This circuite can be used for detection of Basic Acknowledgments form
a Digital Command Control (DCC) Decoder following NMRA
RP9.2.3 (Service Mode). It can be used together with (or to modify)
DCC-MB or TMWDCC.
(ACKDET02.GIF)
Notes
- You can invert the output signal by exchanging the inputs of IC1A (you
have use a knife and some wire)
- If you don´t need an Optocoupler between the track and the PC remove
R1 and connect IC1A,2 direkt to U10A,1
- I have tested this circuite with a Digitrax DH84G Decoder and a current-limiting-resistor
(Resistor R1 of the TMW4 board) of 120Ohms. The Voltage at the track
has been approx. 15V. It drops to approx 3V when the decoder gives the
acknowledge pulse. A puls of 28mV and 2.5ms can then be measured over
R3. This gives an high-level-pulse of approx. 2ms at the input of U10A.
With TMWDCC (Version 1.11) I have successfully read back values
form the decoder.
ACKNOWLEDGE DETECTOR 1
BACK TO DCC
BACK TO MY HOMEPAGE
copyright 1997 by Martin Pischky (martin.pischky@fernuni-hagen.de)
( ACKDET02.HTM / creation 970215 / version 970215 )