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8. Connecting sensors / transducers
8.4 Measuring inputs und additional channels
Measuring instrument ALMEMO
®
204 incorporates four input sockets M0 and
M3; to these, under the new channel numbering scheme, measuring channels
M0.0 to M3.0 are initially assigned. (1) Whereas standard sensors can if nec-
essary provide up to four channels (M0.0 to M0.3, M1.0 to M1.3, etc.), D7 sen-
sors can provide up to 10 (M0.0 to M0.9, M1.0 to M1.9, etc.). The additional
channels can be used in particular for humidity sensors with all the humidity
variables (temperature / humidity / dewpoint / mixture ratio) or for function
channels. Each sensor can if necessary be programmed with several quanti-
ties or scaling settings; and two or three sensors, if pin assignment so permits,
can be combined in a single plug. This device does not incorporate any internal
channels. On the measuring instrument this gives the following channel assign-
ment:
8.5 Potential separation
Since the digital sensors are all operated via the common sensor power sup-
ply, they are all electrically interconnected. So long as the sensors are them-
selves isolated or are operated in isolation, this is not a problem. However, if
two electrical signals (current, voltage) are used, adapter cable ZA-D700-GT
can be connected between them to ensure electrical isolation for power supply
and data lines.
The power supply is isolated by the transformer in the mains adapter or by a
DC/DC converter in connecting cable ZA-2690-UK. Data and trigger cables are
equipped with optocouplers. If analog output cables are not electrically isolated
the recording device or the sensors must be zero-potential.
20 ALMEMO
®
204
M0 M1
0.0
0.1
0.2
0.3
1.0
1.1
1.2
1.3
1. Chan
2. Chan
3. Chan
4. Chan
Sensor channels
with new channel numbering
V5/D6-sensors D7-sensors
5. Chan.
10. Chan.
...
1.4
1.9
...
M2 M3
Содержание ALMEMO 204
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