11
6043-2202
Termination
The MA-43 system has to be terminated and have a fail safe. The last units on the bus
should have termination switched on. The failsafe circuit ensures that when all transmitt-
ters are tristated the line can not float and so cause possible false data readings.
Address assignment
S2 and S3 is two hexadecimal switches which together determine the unit address. The
usable addresses are 0 to 239 (hexadecimal 00 to EF). The addresses 240 to 255 (F0 to
FF) are used for commands and cannot be used as slave addresses. S3 is the high part of
the hexadecimal address and S2 is the low part. If S3 is in position A and S2 in position 1
the unit will become the address A1. Adress 00 will become master. Only one master is
allowed per system.
Direction
Connection
CCITT V.11
no.
Description
Receiver
1
A’ (R+)
Receiver
2B’ (R-)
Transmitter
3
A (T+)
Transmitter
4
B (T-)
5
Shield
Connections
Line connection
(5-Position screw-terminal)
Direction
Connection
CCITT V.24
Signal name
Code
I
2
103
TD/Transmitted data
O
3
104
RD/Received Data
I
4
105
RTS/Request To Send
O
5
106
CTS/Clear To Send
O
6
107
DSR/Data Set Ready
–
7
102
SG/Signal Ground
I
= Input
O
= Output on MA-43
Terminal connection (DCE)
(RS-232-C/V.24, 25-Position D-sub, female)
The definitions R+/R–, T+/T– can be various between
different manufactures.
AUDIN - 8, avenue de la malle - 51370 Saint Brice Courcelles
Tel : 03.26.04.20.21 - Fax : 03.26.04.28.20 - Web : http: www.audin.fr - Email : [email protected]
