14
Operation
Activate/send parameter for low pressure (control command)
Low pressure adjustment (Parameter
[P:741/740]
, Slave device address: "001")
Applied data types
6.4 Adjusting the transmitter
The transmitter is factory-calibrated. It may be necessary to calibrate the Pirani sensor
in the event of contamination, other installation positions, extreme temperature fluctua-
tions, ageing, etc. This is carried out using the "DokuStar" PC software via a connected
control unit or according to customer requirements following the communication instruc-
tions.
Before equalization, the transmitter should be operated at the relevant pressure for ap-
prox. 5 ... 10 minutes long (warm-up time).
For correct zero point equalization, the pressure in the vacuum chamber must be below
1
·
10
-5
mbar.
With controller
DPG 101/DPG 109:
Equalize the transmitter as described in the instructions for the control units.
Via RS-232/RS-485:
Evacuate the vacuum chamber to the pressure p < 1
·
10
-5
mbar.
Set the pressure adjusting point [P:741] to «000» for low pressure and transmit.
Send actual pressure value ([P:740] with value «000000» ) for low pressure (corre-
sponds to p < 1
·
10
-5
); ==> "ur" (under range).
Vent vacuum chamber to atmospheric pressure with air or N
2
; afterwards wait about
10 minutes.
Set the pressure adjusting point [P:741] to «001» for high pressure and transmit.
Set the actual pressure value to the atmospheric pressure («100023» for 1000 mbar).
?
0
0
1
1
0
7
4
1
0
3
0
0
0
1
2
9
C
R
ASCII
48
48
49
49
48
55
52
49
48
51
48
48
48
49
50
57
13
0
0
1
1
0
7
4
1
0
3
0
0
0
1
2
9
C
R
ASCII
48
48
49
49
48
55
52
49
48
51
48
48
48
49
50
57
13
Data type
Description
Size l1 - l0
Example
0
False / true
06
000000 / 111111
1
Positive integer number
06
000000 to 999999
2
Positive fixed comma number
06
001571 equal to 15.71
4
Symbol chain
06
TC_400
7
Positive integer number
03
000 to 999
10
Symbol chain
06
100023
