Difference between revisions of "Two's complement"
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| − | Example: We want to program an offset of -2,5°C for sensor2 so the actual measured temperature will be displayed as follows: Display value sensor2=measured value(in °C) + (- 2,5°C). If we want to convert this to a Basic Action, we know that system values work in 0.5°C so we need to program -5. Following CLI instruction will program an offset -2,5°C for sensor 2: | + | Example: |
| − | "basic action activate 7 2 0 | + | We want to program an offset of -2,5°C for sensor2 so the actual measured temperature will be displayed as follows: Display value sensor2=measured value(in °C) + (- 2,5°C). If we want to convert this to a Basic Action, we know that system values work in 0.5°C so we need to program -5. Following CLI instruction will program an offset -2,5°C for sensor 2: |
| + | "basic action activate 7 2 0 251 0 0" | ||
Revision as of 13:33, 25 October 2020
Values like offset are being written in Two's complement notation. This means that, when using Basic Action, a byte value (0-255) can also represent a negative value.
Byte value is converted in Two's complement:
| Byte Value | Two's complement |
|---|---|
| 128 | -128 |
| ... | ... |
| 251 | -5 |
| 252 | -4 |
| 253 | -3 |
| 254 | -2 |
| 255 | -1 |
| 0 | 0 |
| 1 | +1 |
| 2 | +2 |
| 3 | +3 |
| 4 | +4 |
| 5 | +5 |
| ... | ... |
| 127 | +127 |
Example: We want to program an offset of -2,5°C for sensor2 so the actual measured temperature will be displayed as follows: Display value sensor2=measured value(in °C) + (- 2,5°C). If we want to convert this to a Basic Action, we know that system values work in 0.5°C so we need to program -5. Following CLI instruction will program an offset -2,5°C for sensor 2: "basic action activate 7 2 0 251 0 0"
