S3964R
♦
ProLinx Gateway
Functional Overview
Siemens 3964R Protocol
Driver Manual
Page 46 of 64
ProSoft Technology, Inc.
April 14, 2009
5.4.3 Example 3964R DB-SEND of data to Modbus TCP/IP device
Now let's say the 3964R device needs to send data to the Modbus TCP/IP
device. The 3964R device issues a DB-SEND. The Modbus TCP/IP device
needs to continually poll the ProLinx for an indication of new data.
Use a Modbus Function Code 3 to read header data from the ProLinx
R
ECEIVE
BUFFER
.
The 3964R device issues a DB-SEND telegram to the ProLinx. The
ProLinx device will automatically respond with a DB-SEND Response telegram
back to the 3964R device. The ProLinx will copy the DB-SEND telegram into the
R
ECEIVE BUFFER
.
Use a Modbus Function Code 3 to read the data from the
ProLinx
R
ECEIVE BUFFER
1
Continually watch G for a change in value.
2
Verify the Job Code in L, to make sure this is new DB-SEND data.
3
If the Job Code is 0x1141, then read the
R
ECEIVE BUFFER
.
C
HECK
J
FOR
ERRORS
,
AND
K
AND
L
FOR DATA
.
4
Continually poll the error code, J to verify no errors.
5
Set B to the value in G.
Transmit Buffer
Receive Buffer
Item
Address
Transmit Value
Item
Address
Receive Value
A
(<port#> * 600) + 300
Sequence
Number
G
<port#> * 600
Sequence Number
B
((<port#> * 600) + 300) + 1
Last Receive
Sequence
Number
H
(<port#> * 600) + 1
Last Transmit
Sequence Number
C
((<port#> * 600) + 300) + 2
Blocks
Remaining
I
(<port#> * 600) + 2
Blocks Remaining
D
((<port#> * 600) + 300) + 3
Reserved
J
(<port#> * 600) + 3
Error Code
E
((<port#> * 600) + 300) + 4
Data Count
K
(<port#> * 600) + 4
Data Count
F
((<port#> * 600) + 300) + 5
through ((<port#> * 600) +
300) + 299
Data
L
(<port#> * 600) + 5
through (<port#> *
600) + 299
Data
Port 0 Receive Database (Results of DB-Fetch)
Here is an example of a RK512 DB-SEND initiated from the 3964R
Communication Partner on port 0. This example sends five words of data to the
Modbus TCP/IP device. The values for the five words of data are 11, 22, 33, 44,
and 55.
Word
Value
Description:
0
4
In this example, the Receive Sequence Number will increment from 3
to 4 when the DB-SEND message data has arrived. When this location
changes values, then it signals that new message data has been
received from the 3964R communication partner.
1
X
Transmit Sequence number. This number will not change when a DB-
SEND message has been received from the 3964R communication
partner.
2
0
Reserved.
