Parker TPDM - 11 Serial Interface; Communication Protocol

Parker Hannifin Manufacturing Srl user’s manual TPDM
128
11 SERIAL INTERFACE
The serial communication of the converter is half-duplex, master-slave.
The same serial line can be connected to up to 32 axes, the configuration of the address is
automatic, or by setting a different serial address in each to the Pr27 parameter. It is also
possible to set the transmission speed by using the Pr26 parameter as specified in the table
below:
For the connection diagrams, see the section, Connecting the serial line.
11.1 Communication protocol
The column on the right in the table above shows the time-out value expressed in
milliseconds for each communication speed. This is the time within which the message must
be sent, beginning from the start of each message (STX). If a message is interrupted after this
time, the converter ignores what has been received and waits for the beginning of a new
message.
The message consists of several consecutive bits. The format of the bits is the following:
1 start bit
8 bit of data defined by a following byte enclosed within brackets
1 parity bit (even)
1 stop bit
The structure of the message is the following:
[STX] [CMD+ADDR] [BK+LUN] [PAR] [D0]... [Dn] [CHK]
where:
[STX] = $7E indicator of transmission start. If a field in the message different from STX
assumes the value $7E, this field is followed by a 0 ($00) so that it will not be interpreted as
an [STX].
[CMD+ADDR] = command and address of the peripheral device. This is never 0. This data is
composed in the following way: the first 5 bits (bits 0-4) define the address of the converter
(from 0 to 31); the remaining 3 bits (bits 5-7) define the type of message sent, as described in
the following table:
Pr26 (decimal base)
b/s
time-out (ms)
5
9600
32
6
19200
23
7
38400
23
8
57600
23
9 (default)
115200
23
CMD
bit 7
bit 6
bit 5
type of message
1
0
0
1
converter response
2
0
1
0
reading a pico-PLC instruction
3
0
1
1
writing a pico-PLC instruction
4
1
0
0
reading a parameter
5
1
0
1
writing a parameter
6
1
1
0
bit modification
7
1
1
1
writing a parameter to all the slaves