Measuring inputs and Additional Channels
Advantage
of the device-internal channels: If several sensors are being used
for the same application, they do not have to be reprogrammed and can be
freely exchanged without losing their function channels. If, however, the whole
application operates with just one sensor, then programming in the sensor
itself makes more sense.
On the measuring instrument this gives the following channel assignment:
7.3 Isolation
When building up a working measuring arrangement, it is very important that
there cannot flow any compensation currents between sensors, power supply
and peripherals. This is the case when all measuring points are on the same
potential or when unequal potentials are electrically isolated.
The 5 analog inputs are electrically isolated by photovoltaic relais and between
them a potential difference of at most 50 V DC or 60V AC is permitted. Howe-
ver, combined sensors within one connector and sensors with power supply
are elelctrically connected; therefore they must be operated isolatedly. The vol-
tage at the measuring inputs (between B,C,D and A or -) must not exceed 12V!
The power supply is isolated by the transformer of the mains adapter or by the
DC/DC-converter in the adapter cable ZA2690-UK. Data and trigger cables are
equipped with optocouplers. At electrically not isolated cables of the analog
output, the registration device or the sensors have to be potential free.
ALMEMO
®
2690-8
17
M0 M1 M2 M3 M4
00
10
20
30
03
13
23
33
04
14
24
34
01
11
21
31
02
12
22
32
1. Channel
A2 A1 DC
05
15
25
35
Device-internal channels
Difference M01-M00
Sensor channels
2. Channel
3. Channel
4. Channel
M2
M1
M0
Data cable
AC
DC
DC
DC
ADC
uC
U-
U+
Sensors
Power supply
10..30V=
