Instruction Manual

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