Configuring the Camera
4-10 Basler A500k Series
PRELIMINARY
4.2.3.3 Calculating the Block Check Character
The block check character in any A500k command is the exclusive-or sum (XOR sum) of the bytes
in the descriptor and the data fields. For the write command example shown in Section 4.2.3.2,
the block check character is 0x45. Let’s consider at how this block check character was
calculated.
In this case, we must find the XOR sum of three bytes. This is done by finding the XOR sum of
the first two bytes and then by taking the result and finding the XOR sum of the result plus the third
byte.
Calculating XOR sums is most easily understood when numbers are shown in their binary form,
so in the example calculations shown below, the hexadecimal digits in our command have been
converted to binary.
To find the XOR sum of two binary numbers, you add the two digits in each column using the
following rules:
If both digits are 0, the result is 0.
If both digits are 1, the result is 0.
If one of the digits is a 1 and the other is a 0, the result is 1.
With all of this in mind, here is how the check digit for the write command shown in Section 4.2.3.2
would be calculated:
0100 0110=thebinary representation of 0x46
0000 0001
= the binary representation of 0x01
0100 0111=theXORsumofthefirst two bytes
0100 0111=TheXORsumofthefirst two bytes
0000 0010
= the binary representation of 0x02
0100 0101=TheXORsum
0100 0101=0x45 = the block check character
To Next Page
Loading...
Need help?
General
