Owner's manual

34
tina40e1-b (2011-04)
The interface works in duplex mode. A nine byte string is sent continuously without
a request approx. every 20 ms.
Commands are transmitted to the gauge in a five byte input (receive) string.
• Data rate
9600 Baud set value, no handshake
• Byte
8 data bits
1 stop bit
• 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 for BCG450
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 Response value 13 for BCG450
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 for BCG450
8 Check sum of bytes 1 … 7 0 … 255 Low byte of check
sum
1)
1)
High order bytes are ignored in the check sum.
4.8.1 Description of the
Functions
Operational parameters
Electrical connections
4.8.1.1 Output String (Transmit
)
Format of the output string
Synchronization