Table of Contents
Advertisement
6.3 Pfeiffer Vacuum Protocol for "RS485"
Telegram frame
Telegrams
a2
0
ASCII
48
ASCII
The telegram frame of the Pfeiffer Vacuum protocol contains only ASCII code characters
[32; 127], the exception being the end character of the message
(e.g. a PC) sends a telegram, which is answered by a slave (e.g. electronic drive
unit or transmitter).
a2
a1
a0
a2 - a0
Unit address for slave
– Individual address of the unit ["001";"015"]
*
Action
n2 - n0
Pfeiffer Vacuum parameter numbers
l1 - l0
Data length dn ... d0
dn - d0
Data in data type concerned
c2 - c0
Checksum (sum of ASCII values of cells a2 to d0) modulo 256
C
Carriage return (ASCII 13)
R
Data request ?
a2
a1
Control command !
a2
a1
a0
Data response / control command understood
a2
a1
a0
Error message
a1
a0
1
0
n2
"NO_DEF"
The parameter n2 - n0 does not exist
"_RANGE"
Data dn - d0 are outside the permitted range
"_LOGIC"
Logic access violation
Telegram examples
Read actual pressure value (data query)
(Parameter [P:740], Slave device address: "001")
?
0
0
ASCII
48
48
0
1
1
0
7
48
49
49
48
55
Activate/send parameter for atmospheric pressure (high pressure) (control com-
mand)
Atmospheric pressure adjustment (Parameter [P:741/740], Slave device address: "001")
?
0
0
1
ASCII
48
48
49
0
0
1
48
48
49
*
0
n2
n1
n0
a0
0
0
n2
n1
1
0
n2
n1
n0
1
0
n2
n1
n0
n1
n0
0
6
N
_
_
1
0
0
7
4
49
48
48
55
52
4
0
0
6
1
52
48
48
54
49
1
0
7
4
1
49
48
55
52
49
1
0
7
4
1
49
48
55
52
49
C
. Basically, a master
R
l1
l0
dn
...
d0
n0
0
2
=
?
l1
l0
dn
...
d0
l1
l0
dn
...
d0
O
_
D
E
F
R
A
N
G
E
L
O
G
I
C
0
0
2
=
?
48
48
50
61
63
0
0
0
2
3
48
48
48
50
51
0
3
0
0
1
48
51
48
48
49
0
3
0
0
1
48
51
48
48
49
Operation
C
c2
c1
c0
R
C
c2
c1
c0
R
C
c2
c1
c0
R
C
c2
c1
c0
R
C
c2
c1
c0
R
C
1
0
6
R
49
48
54
13
C
0
2
5
R
48
50
53
13
C
1
3
0
R
49
51
48
13
C
1
3
0
R
49
51
48
13
13
Hide quick links:
Advertisement
Table of Contents
