Campbell Scientific SDM-CAN Datalogger to CANbus Interface - Manual (Page 28)

SDM-CAN Datalogger-to-CANbus Interface
values previously written into the memory buffer. This allows complex bit
patterns to be defined, sometimes changing only as little as one bit at a time.
Parameter Value Data type
13 Unsigned integer, most significant byte 1st.
14 Unsigned integer, least significant byte 1st.
15 Signed integer, most significant byte 1st.
16 Signed integer, least significant byte 1st.
17 4 byte IEEE floating point number, most significant byte 1st.
18 4 byte IEEE floating point number, least significant byte 1st.
3.3.5.3 Transmit individual data values onto the CAN-Bus:
This range of parameter values instructs the datalogger to send a data value to
the SDM-CAN in the format specified; it is loaded into the specified point in a
data frame and then immediately transmitted onto the CAN-Bus. Bits within
the data frame that are not set are left at zero. The data frame length is set to the
minimum size (in whole bytes) required to hold the type of data value
specified.
Parameter Value Data Type
19 Unsigned integer, most significant byte 1st.
20 Unsigned integer, least significant byte 1st.
21 Signed integer, most significant byte 1st.
22 Signed integer, least significant byte 1st.
23 4 byte IEEE floating point number, most significant byte 1st.
24 4 byte IEEE floating point number, least significant byte 1st.
3.3.5.4 Transmit a previously built data frame on to the CAN-Bus (type 25):
When parameter 08 is set to 25, P118 will cause the datalogger to tell the
SDM-CAN to transmit a previously ‘built’ data frame which is stored in the
memory buffer for this packet ID (see data types 7..18 above).
The length of the data frame transmitted is determined by parameter 10. If
number of bits is less than a complete number of full bytes (1-8) then the
number of bytes sent will be rounded up and all unused bits will be set to zero.
The data start bit position will normally be set to one so the data frame starts at
the beginning of the memory buffer. However, you can enter a value greater
than one to allow part of the buffer to be transmitted, which can simplify some
binary masking operations.
The memory buffer is left unchanged after transmission.
20