Table of Contents
Advertisement
PGV...-F200/-F200A...-R4-V19
Operation and communication
5
Operation and communication
5.1
Communication via the RS-485 Interface
The controller and read head communicate via the RS-485 interface during operation. Make
sure that the basic communication settings have been made on the read head, such as setting
the read head address and baud rate.
A distinction is made between request telegrams that the controller sends to the read head and
response telegrams that the read head sends to the controller. Each byte of a request or
response telegram consists of 9 bits (8 data bits + 1 parity bit).
5.1.1
Request Telegram
A request telegram always consists of 2 bytes. The second byte corresponds to the first byte,
but with the 8 data bits of the first byte inverted.
Structure of a Request Telegram
Byte/
bit
Byte 1 Parity
Byte 2 Parity
1. R/W: 0 = response, 1 = request
Meaning of Bits
PAR
Parity
Parity
Parity
Parity
Parity
Parity
Parity
Parity
Parity
Bit 8
Bit 7
Bit 6
Bit 5
1
Req.
Req.
1
bit 4
bit 3
0
~Req.
~Req.
bit 4
bit 3
Req.
Req.
Req.
R/W
bit 4
bit 3
bit 2
1
x
x
x
1
x
x
x
1
x
x
x
1
x
x
x
1
1
0
0
1
1
1
0
1
1
0
R=0
1
0
0
R=0
1
0
0
R=1
Bit 4
Bit 3
Bit 2
Req.
Req.
Req.
bit 2
bit 1
bit 0
~Req.
~Req.
~Req.
bit 2
bit 1
bit 0
Req.
Req.
bit 1
bit 0
A1
A0
x
x
0
0
x
x
0
1
x
x
1
0
x
x
1
1
1
0
x
x
LL
RL
x
x
G=0
B=1
x
x
G=1
B=0
x
x
G=0
B=0
x
x
Bit 1
Bit 0
Function
A1
A0
Request
~A1
~A0
Checksum
Function
Read head address 0
Read head address 1
Read head address 2
Read head address 3
Position inquiry
See chapter 5.1.2
Selection of direction
See chapter 5.1.3
Choice of color blue
See chapter 5.1.4
Choice of color green
See chapter 5.1.4
Choice of color red
See chapter 5.1.4
37
Advertisement
Table of Contents
