Campbell Hausfeld 4-Channel Current/Voltage SDM-CVO4 - Manual (Page 10)

SDM-CVO4 4-Channel Current/Voltage Output Module
3. Power Considerations
The SDM-CVO4 power requirements are large compared to most Campbell
Scientific products, especially when driving significant loads. Care must be taken
to ensure that the power supply can cope with this higher demand.
Alkaline batteries are not recommended for long term applications.
The SDM-CVO4 has two internal power supplies, one for channels 1 and 2 and
one for channels 3 and 4. It will only turn on the power supply for channels 3 and
4 if sent an instruction that sets the output of those channels. If channels 3 and 4
are not used the power consumption is approximately 20 mA lower than when all
outputs are used.
Where supported by the datalogger, and when the application allows it, the SDM-
CVO4 can be shut down to reduce its consumption to less than 0.5 mA. In this
state all outputs are switched off.
4. Installation
Prior to installing the device you need to set the output mode (current or voltage)
of each channel by positioning internal jumpers (see section 4.3). You also need
to set the SDM address of the module (see section 4.4) and additionally consider
any safety issues specific to the installation (see section 4.5).
4.1 Connection to a Datalogger
For datalogger connections, see Table 4-1, below.
Table 4-1. Datalogger to SDM-CVO4 Connections
Connection Order SDM-CVO4 Datalogger Function
First 12 V 12 V on datalogger or external supply Power
Second
or G
C1
C2
C3
or G
SDM-C1 (CR3000, CR5000) or C1 (other dataloggers)
SDM-C2 (CR3000, CR5000) or C2 (other dataloggers)
SDM-C3 (CR3000, CR5000) or C3 (other dataloggers)
Common Ground
Data
Clock
Enable
Multiple SDM-CVO4s may be wired in parallel by connecting the SDM and
power connections from one SDM-CVO4 to the next.
If the total cable length connecting SDM-CVO4s to
SDM-CVO4s, other SDMS and the datalogger exceeds 6 m, the
SDM baud rate may need to be reduced to ensure reliable operation.
Please contact Campbell Scientific for more information.
NOTE
The transient protection of the SDM-CVO4 relies on a low resistance path to
earth. Ensure that the ground return wire has as low a resistance as possible. An
additional G terminal is provided which can be connected directly to the enclosure
earth ground terminal to ensure this. Make sure the ground wire from the SDM-
CVO4 to the datalogger goes to its G terminal and not the AG terminal.
The SDM-CVO4 uses spring-loaded terminal blocks for the connections to the
datalogger which provide quick, vibration resistant, connections. To attach wires,
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