Campbell Hausfeld SDM-CD16AC - Manual (Page 9)

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. For CR10 and 21X
dataloggers, the total length of the cables connecting the SDM-CD16AC's
should not exceed 20 feet.
Total cable lengths in excess of 20 feet will adversely influence
communication performance. For CR7 dataloggers, the total cable length
should not exceed 600 feet.
4.1 Wiring
4.1.1 SDM-CD16AC Power and Control Connections
Refer to Figure 3 and Table 1 for SDM-CD16AC operating power and control
connections to the datalogger.
4.1.2 Controlled Device Connections
ELECTROCUTION HAZARD! USE EXTREME CAUTION
WHEN WORKING WITH HIGH VOLTAGE INPUTS. DO
NOT COME IN CONTACT WITH HOT LEADS! DANGER!
Figure 2 shows how the switches in each channel operate. NO means
“normally open”, NC means “normally closed”. COM means “common” to
NO and NC.
In most applications, the SDM-CD16AC acts as a switch (controllable break)
in one wire of the circuit powering the controlled device. One side of this
break may have power (hot). Figure 4 shows an example.
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