INFICON BCG450 ATM to Ultra-High Vacuum Triple Gauge User Manual
Page 36
36
tina40e1-b (2011-04)
The example is based on the following output string:
Byte
No.
0 1 2 3 4 5 6 7 8
Value 7 5 0 0
242
48 20
13 69
The instrument or controller (receiver) interprets this string as follows:
Byte No. Function
Value Comment
0
Length of data
string
7 set
value
1 Page
number
5
BCG450
2 Status
0
Emission = off
Pressure unit = mbar
3 Error
0
No error
4
5
Measurement
High byte
Low byte
242
48
Calculation of the pressure:
p = 10
((242 × 256 + 48) / 4000 - 12.5)
= 1000 mbar
6 Software
version 20
Software version = 20 / 20 = 1.0
7 Sensor
type
13
BCG450
8 Check
sum
69
5 + 0 + 0 + 242 + 48 + 20 + 13 =
328
dec
= 01 48
hex
High order byte is ignored
⇒
Check sum = 48
hex
= 72
dec
For transmission of the commands to the gauge, a string (frame) of five bytes is
sent (without <CR>). Byte 1 to byte 3 form the data string.
Byte No Function
Value
Comment
0
Length of data string
3
set value
1 Data
→ admissible input strings
2 Data
→ admissible input strings
3 Data
→ admissible input strings
4 Check
sum
(of bytes No 1 … 3)
0 … 255
(low byte of sum)
1)
1)
High order bytes are ignored in the check sum.
Example
4.8.1.2 Input
String
(Receive)
Format of the input string