Measurement Computing CIO-DIO24/CTR3 - Manual (Page 16)

CIO-DIO24/CTR3 User's Guide Functional Details
2.2 K SIP installed for pull-up
2.2 K SIP Dot
+5 VDC
HI
LO
(GND)
n7
U
s
er
C
on
n
ec
to
r
Di
g
it
a
l I
/O
L
in
e
s
n5
n4
n3
n2
n1
n0
n6
COM
Digital
I/O
Port
n = A, B, or C
2.2 K SIP
Dot
+5 VDC
HI
LO
(GND)
n7
U
s
er
C
on
n
ec
to
r
Di
g
it
a
l I
/O
L
in
e
s
n5
n4
n3
n2
n1
n0
n6
COM
2.2 K SIP installed for pull-down
Digital
I/O
Port
n = A, B, or C
Figure 10. Pull-up and pull-down resistor SIPs schematic
To pull-up lines, orient the SIP with the common pin (dot) toward the
HI
end; to pull-down, install the resistor
with the common pin in the
LO
hole.
When installing pull-up and pull-down resistor SIP packs, we recommend using 2.2K, eight-resistor Single
Inline Packages (MCC part number SP-K2.29C). Use a different value only if necessary.
Unconnected inputs float
Unconnected inputs typically float high, but not reliably. If you are using a CIO-DIO24/CTR3 for input and
have unconnected inputs, ignore the data from those lines. You do not have to terminate input lines.
Unconnected lines will not affect the performance of connected lines. Mask out any unconnected bits in
software.
Digital I/O Isolation
To provide external signal conditioning and isolation, you can connect the CIO-DIO24/CTR3 to a CIO-ERB24
or SSR-RACK24. The CIO-ERB24 provides 24 Form C electromechanical relays. The SSR-RACK24 is a
mounting rack for 24 solid-state relays.
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