Schweitzer Engineering SEL-2032, Instruction Manual

Page: 102 / 354

3.32
SEL-2032 Communications Processor Instruction Manual Date Code 20120126
Job Done Examples
Example 6: Modbus Job Done
Figure 3.29 Response Message
Automatic Data
Movement
(Optional)
Some Modbus masters are unable to use 6-digit addressing for function code
03 and are unable to access the data as shown in
Step 5 on page 3.31 . This
example will use a logic point to trigger the movement of user data to a
memory region accessible to these masters. The objective of this step is to
execute the transfer automatically and without additional latency relative to
the computation of the user data region.
Step 1. With meter data now in the Port 16 user region, you can trigger
a 20USER copy to populate its D1 region with the same data
based on the MSET bit status. Use the command
SET A 16
with the following parameters:
➢
ISSUE1=!MSET (make sure to use the !)
➢
MESG1=20USER
The MSET bit is set during SET M equation execution. The
above ISSUE will trigger the 20USER copy immediately
following the SET M operations on Port 16.
Step 2. You can now access this data via Modbus with function code
03. The starting address in the D1 region is 2000h or 8192
decimal. The database will always have a date and timestamp in
the first 4 registers, so the first accessible register with data is
2004h or 8196 decimal. To read the data, send the following
message from the master:
11 from address 17
24 bytes of data following 18
successful function code 3 response 03
•
•
•
SEL-121F IA data
00
14
SEL-121F IB data
00
02
SEL-501 ICY data
xx
xx
CRC-16 code
xx
xx
Courtesy of NationalSwitchgear.com