3 ladder logic – ProSoft Technology MVI56-104S User Manual
Page 55

Ladder Logic
MVI56-104S ♦ ControlLogix Platform
User Manual
IEC 60870-5-104 Server Communication Module
ProSoft Technology, Inc.
Page 55 of 188
November 18, 2009
3 Ladder
Logic
In This Chapter
User-defined Data Types ................................................................... 56
Normal Data Transfer ........................................................................ 65
Special Function Blocks ..................................................................... 67
Ladder logic is required for application of the MVI56-104S module. Tasks that
must be handled by the ladder logic are module data transfer, special block
handling, and status data receipt. Additionally, a power-up handler may be
needed to handle the initialization of the module’s data and to clear any
processor fault conditions.
The sample ladder logic, on the ProSoft Solutions CD-ROM, is extensively
commented, to provide information on the purpose and function of each rung. For
most applications, the sample ladder will work without modification.
All data related to the MVI56-104S is stored in a user-defined data type. At least
one instance of each data type is required before the module can be used. This
is done by declaring a controller tag variable or variable array of the data type in
the Controller Tags Edit Tags dialog box (this will be done automatically if you
use the Add-On Instruction Rung Import file or use a copy of the provided ladder
logic sample).