Campbell Scientific SDM-CD16AC 16-Channel ac/dc Relay Controller - Manual (Page 8)

SDM-CD16AC 16 Channel AC/DC Controller
Cables connecting the terminals of the datalogger and
SDM device should be kept as short as possible to
minimize the risk of corruption of the signals and damage
from induced surges. Where long cable runs (>3 m) are
unavoidable and the cables run outside, some extra
protection may be required for the SDM control terminals.
Please contact Campbell Scientific for further advice.
When connecting wires to the SDM signal terminals please
ensure they are at ground potential before making the
connection, e.g. by touching them to the earth terminal. CAUTION
For datalogger connections, see Table 1.
Multiple SDM-CD16AC's may be wired in parallel by connecting the
datalogger side of one SDM-CD16AC to the next. The CABLE5CBL-L or an
equivalent cable is used to connect the module to the datalogger. A 1-ft cable
length should be sufficient when both datalogger and SDM-CD16AC are
housed within an ENC12/14; a 2-ft length may be required if the datalogger
and SDM-CD16AC are housed at opposite ends of an EN16/18 enclosure.
CRBasic dataloggers should use the SDMSpeed instruction if the cable length
is longer than 20 feet. The maximum recommended cable length for the CR7
is 600 feet. For other Edlog dataloggers, the maximum recommended cable
length is 20 feet.
SDM cables in noisy environments need to be suitably shielded. NOTE
4.1 Wiring
4.1.1 SDM-CD16AC Power and Control Connections
Refer to Figure 2 and Table 1 for SDM-CD16AC operating power and control
connections to the datalogger.
TABLE 1. Datalogger to SDM-CD16AC Connections
(see caution)
Connection
Order
SDM-CD16AC
Datalogger (see note)
Function
First 12 V 12 V on datalogger or Power
external supply
Second Gnd Gnd Common ground
C1 SDM-C1 (CR3000,
CR5000) or C1 (other
dataloggers)
Data
C2 SDM-C2 (CR3000,
CR5000) or C2 (other
dataloggers)
Clock
C3 SDM-C3 (CR3000,
CR5000) or C3 (other
dataloggers)
Enable
4