Functional Overview
S3964R
♦
ProLinx Gateway
Driver Manual
Siemens 3964R Protocol
ProSoft Technology, Inc.
Page 37 of 64
April 14, 2009
5 Functional
Overview
In This Chapter
Product Compatibility ............................................................................ 37
3964R Protocol Overview...................................................................... 37
Communications.................................................................................... 38
Example Messages ............................................................................... 41
Job Processing...................................................................................... 50
Reference Documents........................................................................... 50
5.1 Product
Compatibility
The communication between the gateway and the Modbus TCP/IP processor is
realized through the gateway's database.
5.2
3964R Protocol Overview
5.2.1 The 3964R Protocol in General
The 3964R protocol defined by Siemens is used for bi-directional data exchange
between two peers through a bit-serial point-to-point connection. This protocol
may be additionally embedded in the RK512 telegram level. If 3964R is used with
RK512, each participant can send jobs to its partner and has read
(DB-FETCH)
and write access
(DB-SEND)
to the partner's data. The data exchange is realized
in the form of messages and response messages. The maximum user data
volume is 512 byte per job and 128 byte per message.
3964R without RK512 allows only block wise sending and receiving of data. The
detailed handshake procedure through messages and response messages is not
applicable in this case.
If both partners want to send a job (3964R with RK512) or data (3964R without
RK512) at the same time, the resulting initialization conflict will be solved through
the high/low priority setup. In such a case, one partner will be allocated high
priority and the other one low priority. Thus, in case of an initialization conflict the
device with low priority will defer its job whereas the device with the high priority
will be able to send a job.
The safety of data transmission on the line is guaranteed by a
BCC
checksum.
You should have sufficient knowledge about the 3964R protocol in order to
understand the operation of the driver for the S3964R and to make efficient use
of the example programs.
