二进制11111111转十进制 11111111转十进制( 四 ) _11111111转十进制

0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F. So we count like
0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,10,11,12,13,…
1A,1B,1C,1D,1E,1F,20,21… 2A,2B,2C,2D,2E,2F,30… Using the formula again, we can convert a hex number to decimal quite easily. Nbase=Ddigit * R^unit + …. D1R^1 + D0R^0So hex 6A4 would be:(remember here that R=16) N10=D6 * 16^2 + DA * 16^1 + D4 * 16^0
=6*256 + A(A=decimal10)*16 + 4*1
=1536 +160 +4
=1700
(if you don't see where the 256,16 and 1 came from, refer to the table below)
十六进制 – 二进制数制系统需要大量的数字来表示一个较大的数字。八进制系统在此基础上进行了改进，但不管怎么样十六进制是最好的解决方案，因为它允许我们使用更少的数字。因此，现在十六进制是计算机和PLC中使用的最流行的数字系统（当然我们应该了解每一种数制系统）。
Now we can see that hex FFF is the same as decimal 4095. Try translating hex 76. You should get decimal 118. Try hex 100. You should get decimal 256.
现在我们可以看到十六进制数FFF和十进制数4095是一样的。尝试转换十六进制数76，应该得到的十进制数是118；试试十六进制数100 ，应该得到的十进制数是256 。
Here's a simple hex chart for reference. The top row shows powers of 16 while the bottom row shows their equivalent decimal value. Notice that the numbers get large rather quickly!
这里有一个简单的十六进制图表供参考。第一行显示16的乘方，而后一行显示它们的等效的十进制数值。注意，你可以看到数字会很快变大！

Finally, the hex system is perhaps the most convenient way for us to express or write binary numbers in plc systems. A binary number with a large number of digits can be conveniently written in hex form with fewer digits than octal. This is because 1 hex digit actually represents 4 binary digits.
最后，十六进制系统可能是我们在PLC系统中表达或写入二进制数最方便的方法。一个有大量数字的二进制数可以用比八进制数更少的数字写成十六进制形式，这是因为1个十六进制数字实际上代表4个二进制数字。
Believe me that when we start working with register data or address locations in the advanced chapters it becomes the best way of expressing data. The following chart shows what we're referring to:
相信我，当我们在更高级章节中开始处理寄存器数据或地址位时，十六进制将成为我们表达数据的最佳方式。下面的图表显示了我们所讲到的情况：

From the chart we can see that binary 0111010010100101 is hex 74A5. (decimal 29861) As we can see, when we think of registers, it's far easier to think in hex than in binary or octal.
从图中我们可以看到二进制数0111010010100101是十六进制数74A5（十进制数29861）。正如我们所看到的，当我们想到寄存器时，用十六进制比用二进制或八进制要容易得多。