ProSoft Technology MVI56-101S - Manual (Page 108)

Reference MVI56-101S ♦ ControlLogix Platform
User Manual IEC 60870-5-101 Slave Communication Module
Page 108 of 193 ProSoft Technology, Inc.
August 2, 2011
5.2.6 Data Flow Between MVI56-101S Module and ControlLogix
processor
The following topics describe the flow of data between the three pieces of
hardware, the ControlLogix processor, the MVI56-101S module, and the IEC
60870-5-101 Master unit. Each port on the module is configured to emulate a
common slave device. The database used in the module is used for both ports
and only one port can be utilized at one time.
Slave Driver
The Slave Driver allows the MVI56-101S module to respond to data read and
write commands issued by a master unit on the telecontrol network. The
following flow chart and associated table describe the flow of data into and out of
the module.
Step Description
1 The slave port driver receives the configuration information from the Compact Flash
Disk in the module. This information configures the serial port and define the slave
node characteristics.
2 A Host device 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 message, 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 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.
Review the Installing and Configuring the Module section for a complete list of
the parameters that must be defined for a slave port. The IEC 60870-5-101
Interoperability Document for the MVI56-101S Slave Module contains a listing of
the protocol support supplied in the module.