User Guide
3
Connection with External Supply
Connection with Datalogger Supply
Figure 3 Connection Block Diagrams
If the 21X power supply is used to power the SDM-CD16D, all low
level analogue measurements (thermocouples, pyranometers,
thermopiles, etc.) must be made differentially.
This is a result of slight
ground potentials created along the 21X analogue terminal strip when
the 12V supply is used to power peripherals.
This limitation reduces
the number of available analogue input channels and may make an
external supply for the SDM-CD16D essential.
4. Installation
For correct operation the SDM-CD16D must be installed where there is no
risk of water ingress or condensation.
The order in which connections are made is critical.
Always
connect 12V first
, followed by ground, then the control ports.
For datalogger connections, see Table 1, below. Please refer to Figure 4 for details
of how to use the spring-loaded terminals.
NOTE
CAUTION
GND
EXTERNAL
9 TO 18V DC
+ –
SDM-CD16D
DATALOGGER
12V
C1
C2
C3
SDM-CD16D
DATALOGGER
GND
12V
C1
C2
C3
