3 building and sending data frames, 4 using the interrupt function, Building and sending data frames – Campbell Scientific SDM-CAN Datalogger to CANbus Interface User Manual
Page 40: Using the interrupt function

SDM-CAN Datalogger-to-CANbus Interface
13: 1.0
Mult
14: 0.0
Offset
*Table 2 Program
02: 0.0000 Execution
Interval
(seconds)
*Table 3 Subroutines
End Program
The default setting for the SDM-CAN internal software switches
is 0. The switches must be set by using the data type 32
parameter to enable data transmission. Also remember to check
the jumper settings inside the SDM-CAN if enabling
transmission, as the default setting is for transmission to be
disabled in hardware.
NOTE
3.5.3 Building and Sending Data Frames
The following table shows the parameters used for the process of using a series
of P118s to build a dataframe and then use a further call with data type set to
26 to define part of the working buffer as a remote frame response:
Input Loc Value
Data
type
Start Bit
nbits
Dec
Hex
Indexed
64 bit Frame
Un-initialized frame>>
0x12abcdef12345678
170
0xaa
7
5
N
8
Loaded into frame>>
0x0000000000000aa0
1234 0x4d2
13 17
N
16
Ored
into
frame>>
0x0000000004d20aa0
65535 0xffff 13 31
N
7 Ored
into
frame>>
0x0000001fc4d20aa0
171 0xab
13
8
Y 8
Ored
into
frame>>
0xab00001fc4d20aa0
X
X
26
28
Y
32
Remote Response Frame>>
0x0ab00001 32 bit frame
3.5.4 Using the Interrupt Function
By indexing (‘--‘) the No. of bits parameter, when a new value that an
instruction refers to is received the SDM-CAN I/O interrupt is enabled. This
can be used to set a control port high and run an interrupt subroutine. An
example of using the interrupt function is shown below.
32