The Z449 can be connected as either a unipolar or bipolar device. It can also be configured for two different inut voltage ranges.
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For Unipolar operation, the outputs should be as follows (Assume the MSB has a weighting of 0.5):
Binary out = (Vin/VinMax
For example, for a 10 V range, and an input voltage of 3.75V (.375 * 10), the binary output should be 0.375.
Bit 7 0 .500 Weighting (MSB)
Bit 6 1 .250 Weighting
Bit 5 1 .125 Weighting
Bit 4 0 .0625 Weighting
Bit 3 0 .03125 Weightin
Bit 2 0 .015625 Weighting
Bit 1 0 .0078125 Weighting
Bit 0 0 .00390625 Weighting (LSB)
Sum = 0.25 + 0.125 = 0.375
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For Bipolar operation, the MSB has a weighting of -1. The 2nd MSB has a weighting of +.5, the 3rd MSB has a weighting of +.25, etc
For example, with a 10 V full scale, and an input of -4.53125V, the output would be:
Bit 7 1 -1Weighting (MSB)
Bit 6 1 .5 Weighting
Bit 5 0 .25 Weighting
Bit 4 0 .125 Weighting
Bit 3 0 .0625 Weighting
Bit 2 1 .03125 Weighting
Bit 1 1 .015625 Weighting
Bit 0 0 .0078125 Weighting (LSB)
Sum = -1 + .5 + .03125 + .015625 = -.453125
The easiest way to convert from decimal fractions to binary fractions is with a scientific calculator that has Binary or Hex mode.
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Put the calculator in decimal mode, and enter the decimal fraction.
Multiply the decimal fraction by the binary full scale (in this case X 256).
Place the calculator in binary or hex mode.
Read the binary or hex fraction directly.