IMC C SERIES User Manual page 77

5.2.2 External sensor supply
5.2.2.1 External +5 V supply voltage
At the DSUB-15 connector plugs, there is a 5 V supply voltage available for external sensors or for the
IEPE/ICP Expansion connector. This source is not isolated; its reference potential is identical to the overall
system's ground reference.
The +5 V supply outputs are electronically protected internally against short-circuiting and can each be
loaded up to max. 160 mA (short-circuit limiting: 200 mA). The sensor's reference potential, in other
words its supply-ground connection is the terminal "GND".
The used pins at the DSUB-15 plug Vcc=+5 V and GND fulfill a double function for amplifiers, that can be
used for temperature measurement. They provide the supply for the build in cold junction compensation.
In this case, the 5 V supply can not be used for external sensors.
5.2.2.2 Sensor supply optional (2.5 V to 24 V)
Some modules (C-10xx,
supply. This will not cause an enlargement of the width of those modules. In order to differentiate
between the modules we add a suffix to the name of the module: "..-SUPPLY Find here technical details
of the sensor supply
164
Important: The settings are made via software interface. Make sure that the sensor supply is not set too
high before connecting a sensor. Otherwise, the sensor could suffer damage.
If an isolated, active sensor is both fed with an isolated supply and measured with an isolated channel,
then (due to isolation drift or capacitive interference coupling) an uncontrolled common mode voltage
will emerge unless a common mode voltage is imposed from outside (or, for instance, by targeted
grounding) which may be too strong interference to suppress. Only if the sensor to be supplied with
power is already affected with a common mode voltage due to the measurement setup, or if the -SUPPLY
return lines are already exposed to uncontrolled ground loops, an isolated sensor supply may be
advisable.
The supply voltage is set on each channel group and does apply to all inputs of this group. For the
number of channels per group is depending on the type of device.
© 2018 imc Test & Measurement GmbH
C-12xx , C-41xx ) can optionally be equipped with an adjustable sensor
135 142
.
The supply is unipolar and is wired to the DSUB-15 terminals +SUPPLY
and -SUPPLY. The voltage can be set globally between 2.5 V and 24 V
and is valid for one group of channels.
A bipolar supply voltage of ±15 V instead of the unipolar 15 V is
available as special request. The sensor supply voltage is in this variant
not isolated (to CHASSIS). This is also recommendable in most cases.
With this ±15 V option the pin 6 is the reference at least with the
connector .
170
+15 V via pin 6: GND and pin 3: +SUPPLY, -15 V via pin 6: GND and
pin 12: -SUPPLY, +30 V via pin 12: -SUPPLY and pin 3: +SUPPLY. Each
table with the pinning in chapter "Pin configuration" list in a foot note
the reference, if there is a reference.
Important
Example
Note
imc C-SERIES - Manual, Version 4 R 3 - 2018-10-19
Miscellaneous 77
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