Measurement Computing CIO-EXP-GP - Manual (Page 10)

affect measurements. If the potential exceeds the protection range of the input circuits, the board may be
damaged.
At this time, ignore the other screw terminals located next to the power and ground terminals. They are
needed only with certain sensors and will be explained in those sections.
3.6 Daisy-Chaining CIO-EXP-GP Boards
Connect one CIO-EXP-GP to another using a C37FF-# ribbon cable. Connect from P2 on the ‘upstream’
board to P1 on the ‘downstream’ board. Make sure each of the boards in the chain have a unique channel
selected (CH SEL jumper is set to a different number on each board).
3.7 Connecting a Test Voltage
+
P
E
X
C
IT
A
T
IO
N
. VO
L
T
S
−
SE
NS
E
+
S
E
N
S
E
(+
)I
E
X
C
CH0
−
V
O
LT
S
I
N
OR
COMM
ON
+
VOL
T
S
I
N
S
HORT
ING W
IRE
IN
S
T
ALLED
+EX
C
IT
AT
ION CURRENT
+ S
E
N
S
E
−
P
( −
)IE
X
C
−
S
E
NS
E
+P
+
VOL
T
S
I
N
−
EX
CI
TATI
ON
C
U
RRENT
Make your initial test of the CIO-EXP-GP with a voltage
signal of between -5 and 5V. If you use an AC signal
source, keep the frequency below 70Hz to avoid
attenuation by the CIO-EXP-GP’s low pass filter.
Each input circuit has eight screw terminals associated
with it. These terminals are shown in the diagram to the
right.
To connect a voltage signal to the input circuit you use
three screw terminals as follows:
+SENSE Connect to + voltage
−
SENSE Jumper to
−
P
−
P Connect to Ground
There is not enough room on the board for the full name
next to each terminal so the eight screw terminals
associated with each input circuit are labeled on the
CIO-EXP-GP as follows:
Figure 3-6. Input Screw Terminals
+P Excitation voltage
−
SENSE Low side of input
−
SENSE Hardwired to the other
−
SENSE, same function
−
IEXC Excitation current return
−
P Excitation voltage return, common with
−
IEXC
+SENSE High side of input
+SENSE Hardwired to other +SENSE, same function
+IEXC Excitation current
The use of the terminals is dependent on the type of sensor you have connected to the input circuit, and
the nomenclature on the terminals has been chosen to make the most sense for bridge and RTD sensors.
For voltage and thermocouple sensors the names on the terminals are not typical. Please refer to the
section on the measurement you are making in order to learn how to use the terminals.
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