Ahlborn ALMEMO 5690-2M Operating Instructions Manual page 23

U+
Sensors
M2
M1
M0
electr. isol.
U-
The analog inputs are electrically isolated from one another by means photo-
voltaic relays. A new feature on this device is the additional separation of the
measuring inputs from CPU and power supply. Between all inputs and outputs
(even the analog output cables which are not electrically isolated) the maximum
potential difference permitted is 50 V. The voltage at the measuring inputs
themselves must not exceed 12 V (between B, C, D, and A).
However, some components are not electrically isolated, namely all sen-
sors connected to the same internal power supply ±U or combined sensors
within one connector. For these sensors the electrical isolation may have to be
disabled by means of relay S (see above) or by wire jumper; some inputs would
otherwise be left without reference potential. The relay is set automatically by
element flag 5 ´ISO OFF´ the first time it is connected; (see Manual 6.10.3). How-
ever, with certain connectors (especially divider connectors without power sup-
ply) element flag 5 should be checked and if necessary corrected. These sen-
sors must themselves be isolated or the device must be operated with an elec-
trically isolated power supply (mains adapter or connecting cable ZA3690-UK
with DC/DC converter).
Data and trigger cables are also isolated by means of optocouplers.
DC
ADC
B
A
S
DC
CPU
ALMEMO
Potential separation
Data cable
DC
AC
Power supply
230V≈
DC
DC
10..30V=
® 5690-2M 23