ProSoft Technology 5204SE-MNET-PDPMV1 - Manual (Page 37)

Procedures 5204SE-MNET-PDPMV1 ♦ ProLinx Gateway
User Manual Modbus TCP/IP to PROFIBUS DP-V1 Pass-Through Master
ProSoft Technology, Inc.
Page 37 of 235
December 22, 2009
Set this parameter to a memory address (1 to 32000) to reserve memory space
in a Quantum processor for communication control and data buffers. To send
and receive Modbus TCP/IP messages with a Quantum processor, an area of
processor memory must be set aside and reserved for exclusive use as
communication control and data buffer space. The amount of memory that must
be reserved varies with the amount of communication tasks in the Unity Pro
program. The address you enter in this parameter will be the starting address of
these buffers in %MW processor memory.
How much memory to reserve depends on whether or not you plan to use the
PROFIBUS Acyclic Messaging (Mailbox Messaging) capabilities of the gateway.
The communication control and data buffers are related to the special Defined
Function Blocks (DFBs) created for you by the gateway's ACL. The four (4) basic
DFBs used to transfer PROFIBUS Cyclic data, general module status, and
standard slave diagnostic data require 436, 16-bit registers of communication
control and data buffer space. This is the least amount of space that will need to
be reserved. The ten (10) DFBs used to accomplish Mailbox Messaging require
as much as an additional 1635 registers, for a total of up to 2071 registers, that
should be reserved for these special function buffers.
How you set the M AILBOX M ESSAGING parameter will determine how much
memory will be shown for Control Buffers in the Unity Passthru Memory Map.
Setting M
AILBOX M ESSAGING to N O will show 436 registers reserved for Control
Buffers. Setting M AILBOX M ESSAGING to Y ES will show 2071 registers reserved
for Control Buffers.