ProSoft Technology 5301-MBP-ASCII - Manual (Page 12)

Functional Overview MBP ♦ ProLinx Gateway
Protocol Manual Modbus Plus
Page 12 of 52 ProSoft Technology, Inc.
May 12, 2011
1.2.4 Modbus Plus Global In Access to Database
The MBP module actively exchanges global in (32 words max. per node) and
global out (32 words max.) data on the Modbus Plus network. Priority is given to
these data types to provide a high speed mechanism for the transfer of control
data.
1 The Global In driver reads configuration data from the configuration file. This
data includes the Device Definition File that includes the node address data,
the number of Global In words and where to put this data in the module's
internal database.
2 During the configuration process, the Input File Map is updated out of the
configuration file. The Input File Map informs the module which data registers
in the internal database to feed into the module's input image. This
operational mode is independent of the Global In mode but is commonly used
to transfer global input data from other nodes directly to the processor.
3 The Global In Driver monitors Global In data from other nodes on the
network. If the data matches one of the node addresses in the Device
Definition File and is qualified in terms of length, and so on. the data is
accepted.
4 After the data is accepted, the data is transferred into the module's internal
database. The user via configuration in the Device Definition File determines
the location of the data.
5 As data is read from the other nodes on the network into the module, an
asynchronous process moves the data from the database into the module's
input image. The values to be moved are user determined via configuration of
the Input File Map. Up to 32 words of data can be transferred in this fashion.
6 Status is monitored for each device in the Device Definition File that is
expected to return Global In data to the module. This status is updated on an
on-going basis and is transferred to the Modbus Plus network for processing.
This data includes the node status value and a counter incremented each
time global input data is received.