ProSoft Technology 5204SE-MNET-PDPMV1 - Manual (Page 100)

5204SE-MNET-PDPMV1 ♦ ProLinx Gateway Reference
Modbus TCP/IP to PROFIBUS DP-V1 Pass-Through Master User Manual
Page 100 of 235
ProSoft Technology, Inc.
December 22, 2009
4.4.2 MNETDPV1_BASICVAR Variables and DDTs - M340
These structures hold all the Variables and DDTs required to send and receive
PROFIBUS DP-V0 or DP-V1 cyclic data messages and handle the responses.
Cyclic data is all the data coming from and going to slaves on the PROFIBUS
network on a regular, recurring cycle. Cyclic data transfers are accomplished at a
very rapid, fixed-interval rate in a repeating cycle. The process of completing and
repeating these data transfer cycles is called "polling".
As you can see below, there are four major types of cyclic data:
1 Cyclic input data - data from PROFIBUS Slaves sent to the Master
2 Cyclic output data - data from the PROFIBUS Master sent to the Slaves
3 General Gateway (Module) Status Data - created and reported by the
gateway. (Although this data is not PROFIBUS protocol-specific data, it is
updated along with all the other polling data and, therefore, will be treated as
cyclic data by the automatically-created Application Communication Logic
DDTs and DFBs.)
4 PROFIBUS Slave Diagnostic Data - the PROFIBUS protocol specifies that
each slave send six (6) 8-bit bytes of status and diagnostic data in a fixed
format to the Master as part of the regular polling cycle.
All the DDTs and variables required to use, control, and manage these four types
of cyclic data are contained in the MNETDPV1_BASICVAR structures and sub-
structures.
Cyclic input and output (I/O) data is the data to be transferred based on the
PROFIBUS Master/Slave configuration you did in ProSoft Configuration Builder
(PCB) when you configured specific amounts of inputs and outputs for each
slave on the network.
The ReadCyclicData sub-structures handle PROFIBUS cyclic input data. For
more information, see DFB Read Cyclic Data (page 103).
The WriteCyclicData sub-structures handle PROFIBUS cyclic output data. For
more information, see DFB Write Cyclic Data (page 106).
The ModuleStatus sub-structures handle general gateway status data. For more
information, see DFB Get Module Status (page 109).
The PB_SLVDiagnostics sub-structures handle the standard PROFIBUS slave
diagnostic data. For more information, see DFB Get PROFIBUS Standard Slave
Diagnostics (page 111).