Operating Control Interface Units Using The 3964R Protocol; Notes On The 3964R Protocol - Pepperl+Fuchs IVI-KHA6-4HRX Manual

Operating control interface units using the 3964R protocol

8 Operating control interface units using the 3964R protocol
8.1

Notes on the 3964R protocol

The 3964R procedure was defined to allow the transfer of data via a serial point-to-
point connection in which the majority of data errors and time-outs are detected and
corrected by the protocol. The 3964R protocol is an asynchronous bit-serial transmis-
sion procedure. A character frame consists of one start bit, 8 data bits, one even parity
bit and one stop bit.
Start 0
bit LSB
Bild 8.1: 11-bit character frame
The transmission rate is set via DIP switches S1, S2, and S3.
Communication always starts with a command message either to transmit data
(SEND messages) or to fetch data (FETCH messages).
The control interface unit replies with a "Response" message, with or without data.
A SEND message comprises a message header and data. A FETCH message com-
prises a message header only.
The message header consists of 10 bytes of information about the data target in the
case of a SEND message, or information on the data source, in the case of a FETCH
message.
If the RK 512 Interpreter is used, the message header is structured as follows:
Byte
1
2
3
4
5
6
7
8
9
10
Bild 8.2: Message header
Subject to reasonable modifications due to technical advances.
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IDENT-I • IVI-KHA6-4HRX, IVI-KHD2-4HRX
1 2 3 4
Code Description
00h Message
00h Identifier
'E' Message "input"
x Type of data
xx Target address of data
xx Target address of data
yy Volume of data (high)
yy Volume of data (low)
FFh Coordination marker
FFh Coordination marker
5 6 7
MSB
Check
(high)
(low)
Copyright Pepperl+Fuchs, Printed in Germany
Even Stop
parity bit
yes
yes
yes
no
no
no
no
no
no
no
35