Request a complete data string
The command
$pt
requests a data string as in the following example:
EXAMPLE
#S0001$pt|
Answer: none
The data string is returned as soon as the USH-9 has processed the command.
Request a single measurement value
The reading command
R
together with the index of the requested measurement returns a single
measurement value. In the following example the measurement value with index
01
(in this example
a water level) is requested:
EXAMPLE
#R0001_010cv|EA62;
Answer:
#A0001ok_010cv1461 |07EB;
12.3.9 Sommer CRC-16
The CRC-16 (cyclic redundancy check) used in data transmission of Sommer devices is based on the
ZMODEM protocol. When data are exchanged between two devices the receiving device calculates
the CRC-value. This value is compared to the CRC value sent by the other device to check if the data
were transmitted correctly. Please refer to technical literature or contact Sommer for calculation of
CRC-16 values.
You can
calculate the CRC of a command online .
If you need to compute CRCs automatically, you can implement the following script in your data log-
ger or controller software:
Computation CRC-16 in C/C++
1
crc16 = crc16tab[(
unsigned char
)(crc16>>
8
)] ^ (crc16<<
8
) ^ (
unsigned
int
)(c);
The
crc16tab
array is listed in
.
1
2
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