ProSoft Technology MVI56-DFCMR - Manual (Page 38)

MVI56-DFCMR ♦ ControlLogix Platform Ladder Logic
DF1 Interface Module with Reduced Data Block
Page 38 of 113 ProSoft Technology, Inc.
October 20, 2008
The number of blocks is computed as follows:
BlockCnt = INT(RegCnt/40) + if(MOD(RegCnt,40), 1,0)
If the register count is evenly divisible by 40, the number of blocks is easy to
compute and the ladder is much simpler to write. If the number is not evenly
divisible by 40, special handling of the last block of data must be developed, as it
must transfer less than 40 words. It is recommended that the count values
always be set to values evenly divisible by 40.
The BPFail parameter determines if the module should continue communicating
on the DF1 network when the backplane transfer operation fails. A value of zero
indicates that the module should continue communicating when the backplane is
not operational. If the value is greater than zero, the backplane will be retried the
entered number of times before a failure will be reported and communication will
cease on the ports. When backplane communication is restored, the module will
start communicating with the network. For example, if you enter a value of 10 for
the parameter, the module will stop all DF1 communications if 10 successive
backplane errors are recognized. When a successful transfer is recognized, the
module will resume communications on the network.
The ErrStatPtr parameter defines the location in the module's database where
the error/status data will be stored. If the value is set to -1, the data will not be
stored in the user data area. A value between 0 and 4939 will cause the module's
program to store the data at the specified location.
3.1.2 DF1 Master Commands (DFCMCmd)
This object defines the parameters for each command in the master command
list. The DFCMModuleDef object contains an array of these objects that define
the complete list for each port. The definition of each parameter required for each
command is given below:
Name Data Type Description
Enable INT 0=Disable,1=Continuous,2=Event Command
IntAddress INT Module's internal address associated with the command
PollInt INT Minimum number of seconds between issuance of command
(0-65535 Sec)
Count INT Number of registers associated with the command
Swap INT Swap code used with command
Node INT Address of device to interface with on the DF1 network
Func INT DF1 function code as defined for MVI56-DFCM module
Parameter_1 INT First parameter for function
Parameter_2 INT Second parameter for function
Parameter_3 INT Third parameter for function
Parameter_4 INT Fourth parameter for function