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SDM-SIO1A Serial Input/Output Module
5.5
Datalogger Compatibility
6.
Installation
6
Main body including base
mounting flange
Height:
Width:
Depth:
Weight:
Mounting centers:
The SDM-SIO1A is compatible with our CR6-series, CR800-series, CR1000,
CR3000, CR5000, and CR9000X dataloggers. The CR5000 and CR9000X
operating system must be OS 6 or higher.
The SDM-SIO1A is an addressable interface; therefore, before use, its SDM
address needs to be set by rotating the switch on the side of its case using a
screwdriver. If there is only one SDM device, the address can be left at the
default of 0. (Refer to Section 6.1, Mounting
SDM device.) After mounting as close to the datalogger as possible (to
minimize the cable runs), the interface is connected to the datalogger SDM and
power connections. Refer to Section 6.2, Connection and Wiring
further details.
Study the documentation of the serial device you want to connect to the
SDM-SIO1A to determine the most appropriate method of connection for the
application, for example, RS-232 or RS-485/RS-422, half or full duplex.
Generally, RS-485/RS-422 connections are used for cable runs over 50 m (164
ft) if the device supports them. Once decided, connect the wires to the relevant
SDM-SIO1A terminals. Make sure a connection is made between the ground
connections of the two devices. Use the RG terminal on the SDM-SIO1A for
RS-485/422 connections.
Some serial sensors are supported by Campbell Scientific's Short Cut program.
The SDM-SIO1A can be used with those programs simply by selecting the
relevant serial port number to match the SDM-SIO1A (defined by the SDM
address of the SDM-SIO1A, see Section 6.1, Mounting
taken when interpreting any wiring instructions generated by Short Cut to
account for the differences in wiring a sensor to the SDM-SIO1A rather than
directly to the datalogger.
For other sensors or more complex applications, a CRBasic program needs to
be written to configure and enable the connection between the two devices.
To write a program, it is first necessary to determine how data will be
exchanged. When using the SDM-SIO1A to collect data from a sensor, there
are two options. The datalogger requests data and then picks up the data in the
response from the sensor (often called polling) or the sensor transmits data
"one-way" to the datalogger at fixed intervals based upon its internal timer.
The latter mode is more common but can lead to problems with synchronizing
the sensor measurements with other measurements the datalogger is making
and can also lead to the occasional missed data value if the sensor clock is
running slightly slower than the datalogger clock.
64 mm (2.52 in)
85 mm (3.35 in)
23 mm (0.91 in)
70 g
76.2 mm (3.0 in)
, if there is more than one
(p. 7)
). Care must be
(p. 7)
, for
(p. 8)
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