Pfeiffer PPT 100 - Pfeiffer Vacuum RS-485 Protocol

13
Operation
6.3 Pfeiffer Vacuum Protocol for "RS485"
Telegram frame The telegram frame of the Pfeiffer Vacuum protocol contains only ASCII code characters
[32; 127], the exception being the end character of the message
C
R
. Basically, a master
 (e.g. a PC) sends a telegram, which is answered by a slave  (e.g. electronic drive
unit or transmitter).
Telegrams Data request ?
Control command !
Data response / control command understood 
Error message 
Telegram examples
Read actual pressure value (data query)
(Parameter [P:740], Slave device address: "001")
Activate/send parameter for atmospheric pressure (high pressure) (control com-
mand)
Atmospheric pressure adjustment (Parameter [P:741/740], Slave device address: "001")
a2 a1 a0 * 0 n2 n1 n0 l1 l0 dn ... d0 c2 c1 c0
C
R
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
R
Carriage return (ASCII 13)
a2 a1 a0 0 0 n2 n1 n0 0 2 = ? c2 c1 c0
C
R
a2 a1 a0 1 0 n2 n1 n0 l1 l0 dn ... d0 c2 c1 c0
C
R
a2 a1 a0 1 0 n2 n1 n0 l1 l0 dn ... d0 c2 c1 c0
C
R
a2 a1 a0 1 0 n2 n1 n0 0 6 N O _ D E F c2 c1 c0
C
R
_RANGE
_LOGI C
"NO_DEF" The parameter n2 - n0 does not exist
"_RANGE" Data dn - d0 are outside the permitted range
"_LOGIC" Logic access violation
? 0010074002=?106
C
R
ASCII 48 48 49 48 48 55 52 48 48 50 61 63 49 48 54 13
 0011074006100023025
C
R
ASCII 48 48 49 49 48 55 52 48 48 54 49 48 48 48 50 51 48 50 53 13
? 0011074103001130
C
R
ASCII 48 48 49 49 48 55 52 49 48 51 48 48 49 49 51 48 13
 0011074103001130
C
R
ASCII 48 48 49 49 48 55 52 49 48 51 48 48 49 49 51 48 13