ProSoft Technology MVI56-101S User Manual

Page 103

MVI56-101S ♦ ControlLogix Platform

Reference

IEC 60870-5-101 Slave Communication Module

User Manual

ProSoft Technology, Inc.

Page 103 of 193

August 2, 2011

5.2.4 Sending

Events

The module operates by sending data when the master sends Class 2 polls.
When the slave has an event, it sends the event to the module queue. If the
communication mode is unbalanced, the slave notifies the master that it has an
event to be sent and the master’s next poll should be a Class 1 poll. The slave
then replies to this poll sending the first event to the queue.

There are two ways of sending timestamp events to the module queue. The first
is when a configured point changes its value in the module’s database. This is
actually the way the module would normally send events.

The second method is by using block 9958 (refer to the next section), in which
case ladder logic should be used to send events in this manner. This method is
limited due to the number of events that can be sent to the master. The important
issue about events is that the slave should have its clock synchronized with the
master. The master should send a Sync. Command to the MVI56-101S module
in order to synchronize both clocks. You can also synchronize the module and
the processor clocks using blocks 9970 and 9971 (Refer to the next section).

5.2.5 Command Control Blocks

Command control blocks are special blocks used to control the module. The
current version of the software supports five command control blocks.

Event Messages

Block 9958 identification code sends event messages from the ControlLogix
processor

Block Format for Write

Word Offset in Block Data Fields

Description

0 Block

This field contains the value of 9958 identifying the
block type to the module.

1 Event

Count

Number of events present in the block. This field can
have a value from 1 to 10.

2 to 16

Event #1