SDM-CD16D 16 Channel Digital Control Port Expansion Module
4
Table 1 Datalogger to SDM-CD16D Connections
Connection Order
SDM-CD16D
Datalogger
Function
First
12V
12V on datalogger or
external supply
Power
Second
C1
C2
C3
or G
C1 (Control Port 1)
C2 (Control Port 2)
C3 (Control Port 3)
Common Ground
Data
Clock
Enable
Multiple SDM-CD16Ds may be wired in parallel by connecting the datalogger
side of one SDM-CD16D to the next.
The transient protection of the SDM-CD16D relies on a low resistance path
to earth. Ensure that the ground return wire has as low a resistance as
possible. Where long cable runs are likely, or where lightning damage is a
possibility, the SDM-CD16D can be fitted with gas discharge tubes. Please
contact Campbell Scientific for details.
For CR10/10X, CR23X and 21X dataloggers, the total cable length
connecting SDM-CD16Ds to SDM-CD16Ds and the datalogger
should not exceed 6m. Total cable lengths in excess of 6m will
adversely affect communication performance.
For CR7 dataloggers,
the total cable length can be up to 180m.
4.1 Controlled Device Connections
The SDM-CD16D uses spring-loaded terminal blocks, which provide quick,
vibration resistant, connections. The output terminals are labelled 1 to 16. A
common ground connector is provided between each pair of terminals
Use a screwdriver in either the top or front slot, as appropriate, to open the
terminal spring. Strip any insulation from the wire to give 7 to 9mm bare wire.
Push the wire into the opening, and, while holding it in position, withdraw the
screwdriver to release the spring. The wire will now be firmly held in place. See
Figure 4, below.
You cannot reliably insert more than one solid-core wire into one
terminal connector unless the wires are soldered or clamped
together. When inserting more than one stranded wire, twist the bare
ends together before insertion.
NOTE
NOTE
