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EPPxxxx | Industrial housing · 0 次阅读

Presentation, index 0x80n0:02

Index 0x80n00:02 Presentation offers the possibility to change the method of representation of the measured value.

Presentation, index 0x80n0:02 1:
Index 0x8002, selection of the representation

3 value representations are possible in the 16bit PDO:

  • Signed Integer (default setting):
    The measured value with resolution 1 bit = 1/10°C is displayed signed in two's complement.
    Maximum representation range for 16-bit = -32768 ... +32767, corresponding theoretically to -3276.8°C ... +3276.7°C (in reality the measured value is limited by the set transformation).

    Example:
    • 1000 0000 0000 0000bin = 0x8000hex = - 32768dec
    • 1111 1111 1111 1110bin = 0nFFFEhex = - 2dec
    • 1111 1111 1111 1111bin = 0nFFFFhex = - 1dec
    • 0000 0000 0000 0001bin = 0n0001hex = +1dec
    • 0000 0000 0000 0010bin = 0n0002hex = +2dec
    • 0111 1111 1111 1111bin = 0x7FFFhex = +32767dec
Presentation, index 0x80n0:02 2:
Selection options transformation
  • High resolution:
    The measured value with resolution 1 bit = 1/100 °C is displayed signed in two's complement, see there. Maximum representation range for 16-bit = -32768 ... +32767, corresponding theoretically to -327.68°C ... +327.67°C (in reality the measured value is limited by the set transformation).

    The achievable accuracy is not increased by the finer representation! However, the additional decimal place can be useful for control tasks, where the internal ADC resolution limits the resolution: for example, real measured value changes of 60 mK can be read for type K:
Presentation, index 0x80n0:02 3:
Representation of measured value change thermocouple type K

Measured value

Output (hexadecimal)

Output (signed integer, decimal)

Corresponds in 1/10 °C

Corresponds in 1/100 °C

-200.0 °C

0nF830

-2000

-200 °C

-20 °C

-100.0 °C

0nFC18

-1000

-100 °C

-10 °C

-0.1 °C

0nFFFF

-1

-0.1 °C

-0.01 °C

0.0 °C

0n0000

0

0 °C

0 °C

0.1 °C

0n0001

1

0.1 °C

0.01 °C

100.0 °C

0n03E8

1000

100 °C

10 °C

200.0 °C

0n07D0

2000

200 °C

20 °C

500.0 °C

0x1388

5000

500 °C

50 °C

850.0 °C

0x2134

8500

850 °C

85 °C

1000.0 °C

0x2170

10000

1000 °C

100 °C

Table:  Output of process data and measured value

  • Absolute value with MSB as sign:
    The measured value with resolution 1 bit = 1/10 °C is output signed in the signed amount representation.
    Maximum representation range with 16 bit = -32768 ... +32767, corresponding theoretically to -3276.8°C ... +3276.7°C (in reality the measured value is limited by the set transformation)

    Example:
    • 1111 1111 1111 1111bin = 0nFFFFhex = - 32767dec
    • 1000 0000 0000 0010bin = 0x8002hex = - 2dec
    • 1000 0000 0000 0001bin = 0x8001hex = - 1dec
    • 0000 0000 0000 0001bin = 0n0001hex = +1dec
    • 0000 0000 0000 0010bin = 0n0002hex = +2dec
    • 0111 1111 1111 1111bin = 0x7FFFhex = +32767dec