ProSoft Technology 5201-DFNT-104S - Manual (Page 110)

104S v2 ♦ ProLinx Gateway Reference
(Firmware v2.xx) Protocol Manual
Page 110 of 157
ProSoft Technology, Inc.
March 19, 2010
The DB Input Window Start parameter defines the ProLinx database starting
register where the command block request should be transferred to (from the
remote node to the ProLinx gateway). For the example above, a Modbus TCP/IP
client would send a control block request to the ProLinx gateway starting at
database start register 3000. A value of -1 disables this functionality.
The DB Output Window Start parameter defines the ProLinx database starting
register where the control block response should be transferred to (from the
ProLinx gateway to the remote node). So some control blocks will require a
response from the gateway (for example the control block to retrieve the current
time from the gateway). For the example above, the remote node must read the
control block response from the ProLinx gateway starting at database start
register 3100. A value of -1 disables this functionality.
General Command Block Structure
A command request block will have the following general structure. The
command request block should be copied starting at the database address given
by the configuration parameter DB Input Window Start:
Word Offset Description
0 Block ID1 - Command Request Without Response
1 Block ID2 - Command Request With Response
2 to 98 Command Request Data
99 Block ID1 - Command Request Without Response
Where:
Command Request Without Response Block is transferred from the remote
node to the ProLinx gateway to request a special task that does not require
data back from the gateway. For example, a Set Time command block sets
the gateway time but does not require data back from the gateway.
Command Request With Response Block requires data back from the
gateway. The response block is copied at a different database area. For
example, a Get Time command block requests the gateway time information.
So a command block may:
Perform command request without response only
Perform command request with response only
Perform both command request with response and command request without
response
The ProLinx gateway recognizes a new block command request if:
A new command request block ID is received at word offsets 0 and 99
The same command request block ID is received at word offsets 0 and 99
If these conditions are fulfilled the gateway will process the request and response
command blocks.