YSI WaterLog Series, Owner'S Manual

Page: 87 / 174

For 3-byte signed values, if the value is greater than 131071, subtract 131072 from the value and
change the sign to negative.
For 2-byte signed values, if the value is greater than 2047, subtract 2048 from the value and
change the sign to negative.
For 1-byte signed values, if the value is greater than 31, subtract 32 from the value and change
the sign to negative.
Finally, divide the number by 10^Precision. Thus if 2 was chosen as the Precision, divide the
number by 100 (10^2), 3 would be 1000 (10^3), etc.
The following are 3-byte, 2 Precision Signed-Magnitude examples:
H^g = (32768 + 1920 + 39) = 34727 H in the left position = 32768
^ in the middle position = 1920
g in the right position = 39
---------
Total = 34727
This is less than 131071 so just divide by 100.
Divide by 100. 34727 / 100 = 347.27 = final value.
rSx=( 1216 + 56) = 206072 r in the left position = 204800
S in the middle position = 1216
x in the right position = 56
------------
Total = 206072
This is greater than 131071 so subtract it from 131072.
206072 - 131072 = 75000
Then divide by 100 and change the sign. (-1) * 75000 / 100 = -750.00 = final value.
Appended battery values are encoded using a single byte. To decode the appended battery
voltage use the weighted value for the character from the right hand column and multiply it by
0.3124, then add 0.311.
For example, if the single character for the appended battery voltage is ‘h’, the weighted value of
the right most character column is 40. Thus 40 * 0.3124 + 0.311 = 12.81 volts.
Date and time are transmitted as 3 bytes each: one byte for date, one for month, one for year and
so on. An example of date and time values in binary follows, again using the right hand column
of the look up table.
CLHWxs C = 3 = month, March; L = 12 = Date, the 12 ; H = 8 = Year, 2008.
th
W = 23 = Hours; x = 56 = minutes; s = 51 = seconds.
System 5000
Outputs 6-29
TM