ProSoft Technology MVI46-DFCM - Manual (Page 64)

MVI46-DFCM ♦ SLC Platform Reference
DF1 Communication Module
Page 64 of 103 ProSoft Technology, Inc.
October 20, 2008
5.2.2 Data Flow between MVI46-DFCM Module and SLC Processor
The following topics describe the flow of data between the two pieces of
hardware (SLC processor and MVI46-DFCM module) and other nodes on the
DF1 network under the module's different operating modes. Each port on the
module is configured to emulate a DF1 master device or a DF1 slave device. The
operation of each port is dependent on this configuration. The sections below
discuss the operation of each mode.
Slave Driver Mode
The Slave Driver Mode allows the MVI46-DFCM module to respond to data read
and write commands issued by a master on the DF1 network. The following flow
chart and associated table describe the flow of data into and out of the module.
Step Description
1 The DF1 slave port driver receives the configuration information from the SLC processor.
This information configures the serial port and define the slave node characteristics. The
module simulates N-files to permit remote access of the database. Each file has a fixed
length of 200-word registers.
2 A Host device, such as the Rockwell Automation PLC or an HMI application issues a
read or write command to the module's node address. The port driver qualifies the
message before accepting it into the module.
3 After the module accepts the command, the data is immediately transferred to or from
the internal database in the module. If the command is a read command, the data is read
out of the database and a response message is built. If the command is a write
command, the data is written directly into the database and the M1 file and a response
message is built.
4 After the data processing has been completed in Step 3, the response is issued to the
originating master node.
5 Counters are available in the Status Block that permit the ladder logic program to
determine the level of activity of the Slave Driver.
Refer to Module Configuration (page 21) for a complete list of the parameters
that must be defined for a slave port. The slave driver supports the following DF1
command set: