INFICON BCG450 ATM to Ultra-High Vacuum Triple Gauge - 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 ). 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