Campbell Hausfeld SDM-CAN - Manual (Page 24)

SDM-CAN CAN-Bus Interface User Guide
Table 3-1 Typical settings of the CAN Speed Parameters
Baud rate TQUANTA TSEG1 TSEG2
1M 1 5 2
800 K 1 7 2
500 K 2 5 2
250 K 4 5 2
125 K 8 5 2
50 K 16 7 2
20 K 40 7 2
The same three values for these parameters should be used in every
call of the P118 instruction in the datalogger program. NOTE
ID (Parameters 05:, 06:, 07:)
A CAN data frame includes an identifier (ID) which is used by devices on the
network to identify each type of packet on the network. Some standards reserve
certain IDs or ranges of IDs for specific functions. The J1939 SAE standard for
instance reserves certain parts of the ID to identify the type of data, its priority and
its origin (see Appendix C for a discussion of this standard and use with the
SDM-CAN). The SDM-CAN is, however, transparent to any special meaning of
the ID; each packet is only referenced by the full ID. The CAN 2.0A standard uses
an ID with 11 bits, while CAN 2.0B uses 29 bits.
When entering IDs into Instruction P118, three parameters are used. This is
because the ID size, in number of bits, is too large to be encoded into a single
parameter.
The first ID parameter (parameter 05) sets bits 0..10, entered as a number between
0 and 2047. This parameter also determines whether an 11-bit or a 29-bit Identifier
is set. If you index this parameter then an 11bit Identifier is set; the following two
parameters are then irrelevant and are normally left at zero.
The second ID parameter (parameter 06) encodes bits 11..23 entered as 0 to 8191.
The third ID parameter (parameter 07) is for bits 24 to 28 entered as 0 to 31.
CAN networks either work with 11 or 29 bit IDs. As a general rule
you cannot have packets with different length IDs on the same
network. Therefore make sure parameter 05 specifies the same
length ID for all calls of P118. NOTE
Data Type (Parameter 08:)
This parameter determines the type of data involved and/or the type of function
this call of P118 will perform. The data type parameter is entered as a two-digit
parameter in the range of 0-33. A summary table of the data types described below
is given in Appendix B of this manual for quick reference.
As a general rule, this function is applied only to data packets with the ID
specified in parameters 05..07. The action applies to a certain number of bits
within the data frame that is specified in parameter 10, starting at the bit specified
in parameter 09. In some cases the number-of-bits parameter is overridden
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