Introducing Block I/O
Chapter 1
1-5
Voltage Input
Voltage inputs can be either single-ended or differential. In the voltage
mode, a signal applied between inV0 and the combination of RET in0
shorted to GND in0 provides a single-ended input mode. A signal applied
between inV0 and RET in0 provides a differential input mode. The four
terminals for ground are internally connected together to form the analog
input common. In either input mode (single-ended or differential) the
common mode voltage between any input terminal and analog input
common cannot exceed 11V or unreliable operation will occur. The figures
below show examples of differential input mode and single-ended input
mode.
10V
GND in0
RET in0
inI0
inV0
10V
inV0
RETin0
GNDin0
inI0
Differential Input Mode
Singleended Input Mode
(no connection)
(no connection)
Current Input
When using the 0–5V or +5V range, an internal precision 249
Ω
shunt is
provided on each input. Input current is measured when the I
IN
and V
IN
terminals are connected together. To get the proper input voltages, you
must indicate that the current shunt is connected when you configure the
module at powerup. A +24V power supply is provided for two-wire
current transducers.
5V
inV0
inI0
RETin0
GNDin0
Current Input
I
Each range setting has a margin of 2.5% to allow for compensation of
system or calibration inaccuracies.
