INFICON BPG402-Sx ATM to Ultra-High Vacuum Gauge User Manual
Page 31
tina46e1-a (2010-03) BPG402.om
31
• TxD
Pin 13
• RxD
Pin 14
• GND
Pin 5
(Sensor cable connector)
The complete output string (frame) is nine bytes (byte 0 … 8). The data string is
seven bytes (byte 1 … 7).
Byte No Function
Value
Comment
0
Length of data string
7
set value
1
Page number
5
hot cathode gauges
2 Status
→ Status byte
3 Error
→ Error byte
4
Measurement high byte
0 … 255
→ Calculation of pressure value
5
Measurement low byte
0 … 255
→ Calculation of pressure value
6
Software version
0 … 255
→ Software version
7
Sensor type
12
for BPG402-Sx
8
Check sum
0 … 255
→ Synchronization
Synchronization of the master is achieved by testing three bytes:
Byte No Function
Value
Comment
0
Length of data string
7
set value
1
Page number
5
hot cathode gauges
8
Check sum of bytes No 1 … 7
0 … 255
low byte of
check sum
1)
1)
High order bytes are ignored in the check sum.
Bit 1
Bit 0
Definition
0 0
emission
off
0 1
emission 25
μA
1
0
emission 5 mA
1 1
degas
Bit 2
Definition
x
not
used
Bit 3
Definition
0
⇔ 1
toggle bit, changes with every
string received correctly
Bit 5
Bit 4
Definition
0
0
current pressure unit mbar
0
1
current pressure unit Torr
1
0
current pressure unit Pa
Bit 6
Definition
0
filament 1 active
1
filament 2 active
Bit 7
Definition
x
not
used
Electrical connections
4.9.1.1 Output String (Transmit
)
Format of the output string
Synchronization
Status byte