6.6 Connection options via interface RS-485
DCU 002
DCU 110 - 310
HPU
USB/RS485-converter
T P S
M V P
RS485
RS485
RJ45
M12
M12
DC in
DC in
M12
M12
M12
M V P
H i P a c e
H i P a c e
Fig. 8:
Connection options via interface RS-485
Connecting Pfeiffer Vacuum display and control panels or PC
At interface RS-485, one external control panel can be connected in each case.
1. Use the respective connection cable supplied with the control panel or from the range of accesso-
ries.
2. Use the option to connect a PC via the USB/RS-485 converter.
6.7 Pfeiffer Vacuum protocol for RS-485 interface
6.7.1 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 telegram 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).
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";"255"]
● Group address "9xx" for all identical units (no response)
● global address "000" for all units on the bus (no response)
*
Action according to telegram description
n2 – n0
Pfeiffer Vacuum parameter numbers
I1 – I0
Data length dn to d0
dn – d0
Data in the respective data type
(see chapter “Data types”, page 27)
.
c2 – c0
Checksum (sum of ASCII values of cells a2 to d0) modulo 256
C
R
carriage return (ASCII 13)
Interfaces
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