AED
CONNECTING INTERFACES AND I/OS
32
1. RS-485 with 4-wire connection
This connection allows the full range of AED functions with a maximum cable length
of 1000 m.
2. RS-485 with 2-wire connection
This connection also allows cable lengths of 1000 m. However, in this case only COF
formats 64
…
69 are permitted. Therefore, when starting up, the relevant COF com
mand must be the first command sent. Moreover, you must not use the command
MSV?0;, because in this mode of operation, measurement output can no longer be
interrupted with the command
STP;.
The position of the bus termination switch is based on the position of the AED in the bus
system. Bus termination may only be switched on at the end points of the bus (max. 2
termination resistors active), also see section 7.1.1, page 26. If necessary, slide the bus
termination switch on the AED to on and activate the resistors with the bus commands
STR1;TDD1;. The factory setting is off.
7.2.2
Connecting the diagnostic bus
2
16
1
15
TA/RA
GND/0 V
KL4
TB/RB
11
13
Fig. 7.7
Connecting the diagnostic bus
Also see section 7.1.4 on page 30 for more information on the diagnostic bus.
