Intab PC-Logger 3100i, How To Use Manual, Page: 19 / 49

19
BASIC UNIT
Connecting Sensors and Transducers (cont.).
The impedance between the positive and negative inputs to ground is of the
order of several M
Ω
. They must therefore never be allowed to float outside
the specified common mode range, but must be referenced to ground in some
way.
Use the miniature switches to set up the channels as single ended inputs.
These switches ground the negative input of corresponding channels.
Before doing this, you have to make sure that no potential exists between the
negative outputs of your transducers as his could burn out your wiring or
worse.
You must also be careful not to introduce ground loops in your signal paths.
To maintain the validity of your measurements you have to take the common
mode range into account.
Common mode range is +/-10V for most ranges.
LOGGED
SIGNAL
+
-
CHANNEL
GND (ref)
MAX 10V
COMMON MODE SIGNAL
AAC-2 : "COMMON MODE"
The inputs will not be damaged by voltages above this as long as they are
within 30V off signal ground.
The following sections of this manual will provide some examples of how
transducers can be connected.
NOTE
that these instructions also are valid for units with jack panels . You
have to open the lid to make those channels single ended that should be single
ended.
”3100i” signal ground is here also available as two black banana jacks on one
of the sides of the casing.
The jack panel must be looked upon as a device external to the logger itself. It
is built into the logger casing only for practical reasons.