Campbell Scientific SDM-CAN Datalogger to CANbus Interface - Manual (Page 18)

SDM-CAN Datalogger-to-CANbus Interface
An additional I/O terminal is provided on the SDM-CAN for use with
dataloggers which support interrupt driven logging events. This might typically
be used to enable the rapid capture of time critical CAN data, where the I/O
port can be used to indicate to the datalogger that data has been captured and is
available for immediate collection (see below). In most applications this
function will not be used and the terminal need not be connected. Where it is
required, it should be connected to a digital input on the datalogger.
2.3.1 LED Status Indication
When power is applied to the SDM-CAN the red ‘STATUS’ LED will flash to
indicate the current status of the unit as a result of the power-up checks.
If the LED flashes once, the module has passed all power-up tests and should
operate correctly. The other flash sequences are shown below. Problems with
the operating system can normally be fixed by reloading the operating system.
Please contact Campbell Scientific if you are unable to resolve the problem.
TABLE 2-2. LED Status Indication
Number of flashes Indication
1 SDM-CAN is ok.
2 OS signature bad.
10 OS downloaded has failed.
2.4 Connection to CAN-Bus.
The physical connection to the CAN-Bus is achieved by one of two methods
which is by either the 3 way un-pluggable screw terminals or the 9 pin ‘D’ plug
which conforms to CIA draft standard 102 version 2.
The basic connections of the CAN-Bus to the three-way terminal are CAN
High, CAN Low and 0V ground reference. The 3 way screw terminal is
marked as ‘G H L’ on the SDM-CAN case, where G=Ground, H=CAN High,
L=CAN Low.
The CIA, 9 pin, ‘D’ connector pin configuration is shown in TABLE 2-3.
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