Ladder logic, Module data object (dfcmmoduledef), 3 ladder logic – ProSoft Technology MVI69-DFCM User Manual
Page 35

Ladder Logic
MVI69-DFCM ♦ CompactLogix or MicroLogix Platform
DF1 Interface Module
ProSoft Technology, Inc.
Page 35 of 117
November 3, 2008
3 Ladder
Logic
In This Chapter
Module Data Object (DFCMModuleDef)................................................ 35
Adding the Module to an Existing CompactLogix Project ...................... 38
Adding the Module to an Existing MicroLogix Project............................ 42
Ladder logic is required for application of the MVI69-DFCM 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 Object (DFCMModuleDef)
All data related to the MVI69-DFCM is stored in a user defined data type. An
instance of the data type is required before the module can be used. This is done
by declaring a variable of the data type in the Controller Tags Edit Tags dialog
box. The structure of the object is displayed in the following table.
Name Data
Type
Description
BlockTransferSize
INT
60, 120 or 240
ReadData
INT[720]
Data read from MVI69-DFCM
WriteData INT[720]
Data
written to MVI69-DFCM
BP
DFCMBackplane
Variables for BP logic
ModuleStatus DFCM_STATUS Module
Status
BlockRequest
DFCMBlockRequest
Bits to request special blocks
ReadClock
DFCMClock
Time read from MVI69-DFCM
WriteClock
DFCMClock
Time written to MVI69-DFCM
CommandControl
DFCMCommandControlPorts
Used for Command Control operation
EventCommand DFCMEventCommandPorts Used for Event Command operation
SlavePollingControl DFCMSlavePollingControlPorts
Slave polling control
SlaveStatus
DFCMSlaveStatusPorts
Status codes for each slave
This object contains objects that define the configuration, user data, status and
command control data related to the module. Each of these object types is
discussed in the following topics of the document.