ProSoft Technology MVI69-DNPSNET - Manual (Page 37)

Ladder Logic MVI69-DNPSNET ♦ CompactLogix or MicroLogix Platform
Distributed Network Protocol Interface Module
ProSoft Technology, Inc. Page 37 of 119
November 3, 2008
3 Ladder Logic
In This Chapter
™ Module Data Objects ............................................................................. 37
™ Adding the Module to an Existing CompactLogix Project ...................... 41
™ Adding the Module to an Existing MicroLogix Project............................ 45
Ladder logic is required for application of the MVI69-DNPSNET 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.
3.1 Module Data Objects
All data related to the MVI69-DNPSNET is stored in one user defined data type,
containing data transfer and status data, and the DNP datasets. Any time an
array's size is altered in the RSLogix 5000 software, all the data in the object can
be set to zero. Because the array sizes may need to be adjusted for the data
types in an application, the user defined data should be adjusted prior to the
module being placed in service (if the default configuration does not contain
enough data points for the application).
An instance of each data type is required before the module can be used. This is
accomplished by declaring variables of the data types in the Controller Tags Edit
Tags dialog box. Each object is discussed in the following topics.
3.1.1 DNPModuleDef Object
The DNPModuleDef object contains all the MVI69-DNPSNET module status data
and data transfer variables. The object has the following structure.
Name Data Type Description
Status DNPSlvStat
Data DNPData
CMDcontrolbits DNPCMDBits
ReadClock DNPClock
WriteClock DNPClock
BI_Events DNPBIEvntBlk
AI_Events DNPAIEvntBLK
BP DNPBackplane