ProSoft Technology MVI46-DFCM - Manual (Page 69)

Reference MVI46-DFCM ♦ SLC Platform
DF1 Communication Module
ProSoft Technology, Inc. Page 69 of 103
October 20, 2008
If the DF1 master port is configured to support the DF1 half-duplex protocol, the
master port can be used to route messages between slaves. Peer-to-peer
communication is accomplished by the master constantly polling all the slaves on
the network and relaying the messages received. The slaves must contain ladder
logic with MSG commands to generate and accept messages. This routing can
be used in conjunction with the normal command processing discussed above. If
the slave node to be polled is not included in the command list, a special
command is required in the command list. Enter a 999 in the Enable Code and
the slave's node address in the Node Address fields of the command. No other
parameters are required for a device poll message. This command will force the
master port to issue an enquiry request to the slave device without first issuing a
command. Any messages held in the slave's message queue will be sent to the
master and the master will route the messages that do not contain the master's
station code.
5.2.3 Module Data
All data related to the MVI46-DFCM module is stored in user defined data areas.
You must up the data areas to match the specific application for which the
module is used. Each data area is discussed below:
Configuration Data
You configure the module by entering values in a user defined data table. In the
example ladder logic, file N10 stores the general module configuration
information. N11 stores the command list for port 2. Each register in the files has
an associated symbol and description to help you enter the data. Refer to MVI46-
DFCM Configuration for the items that must be configured for the module, and
their associated location in the M0 file.
Backplane Parameters
All data transferred between the SLC processor and the module is held in the
module's M1 file. This simplifies the ladder logic. In order to read data in the
module, copy the specific data area in the M1 file into a user defined file. Repeat
this operation for each data area. Remember, the maximum data area that can
be copied with the COP instruction is 128 words. In order to write data to the
module, copy the data in the user defined file to the specific data area in the M1
file. The read and write data operations should be limited to the M1 words 0 to
4999. The modules status data can be read from the M1 file starting at register
7600.
Only two parameters are used in this section of the configuration. The Backplane
Fail 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 on the network. For example, if you enter a value of 10 for
the parameter, the module will stop all DF1 communications if 10 successive