Ladder logic is required for application of the MVI56-DFCMR 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 Configuration

Objects

Configuration of the module is performed by filling in the values in the module
object defined in the Controller Tags Edit Tags dialog. Each parameter required
by the module has a defined location in the object. The tables and discussions
below describe the parameters set in the dialog box. You can view these tables
by opening the data type under the User Defined Data Type option in the
Controller Organization window.

3.1.1 Data Transfer Parameters (DFCMModule)

Name Data

Type

Description

WriteStartReg

INT

Start reg to transfer from PLC to module

WriteRegCnt

INT

Number of registers to write from PLC

ReadStartReg

INT

Start reg to transfer from module to PLC

ReadRegCnt

INT

Number of registers to transfer from module

BPFail INT

Determines module operation if BP fails
0=continue,>0=number of retries before comm shutdown

ErrStatPtr

INT

Internal DB start register for status data (-1=Ignore)

This object defines the parameters for data movement between the module and
the processor. Values entered determine the ladder logic and data size required
in the application. The ReadData and WriteData arrays must be sized to or larger
than the count values entered. The ladder logic must process the number of
blocks of data to be transferred.