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EL32xx | Analog Input Terminals RTD (Pt100, Pt1000, ...) · 0 次阅读

PDO presentation, 0x80n00:02

Index 0x80n00:02 "Presentation" offers the possibility to change the digital presentation of the measured value in the 16-bit value. Three value presentations are possible in the 16-bit PDO:

PDO presentation, 0x80n00:02 1:Fig.164: Setting the presentation of the measured value in 0x8000:02 "Settings"
  • Signed (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 RTD transformation).
    PDO presentation, 0x80n00:02 2:
    Example:
    • 1000 0000 0000 0000bin = 0x8000hex = - 32768dec
    • 1111 1111 1111 1110bin = 0xFFFEhex = - 2dec
    • 1111 1111 1111 1111bin = 0xFFFFhex = - 1dec
    • 0000 0000 0000 0001bin = 0x0001hex = +1dec
    • 0000 0000 0000 0010bin = 0x0002hex = +2dec
    • 0111 1111 1111 1111bin = 0x7FFFhex = +32767dec
  • 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, but can be extended by user scaling).
    The achievable accuracy is not increased by the more detailed presentation! However, the additional decimal place can be useful for control tasks, where the internal ADC resolution limits the resolution.

Measured value and process data output

Measured value

Output
(hexadecimal)

Output
(signed integer, decimal)

In 1/10°C,
corresponds to

In 1/100°C,
corresponds to

-250.0°C

0xF63C

-2500

-250°C

-25°C

-200.0°C

0xF830

-2000

-200°C

-20°C

-100.0°C

0xFC18

-1000

-100°C

-10°C

-0.1°C

0xFFFF

-1

-0.1°C

-0.01°C

0.0°C

0x0000

0

0°C

0°C

0.1°C

0x0001

1

0.1°C

0.01°C

100.0°C

0x03E8

1000

100°C

10°C

200.0°C

0x07D0

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

  • Absolute value with MSB as sign:
    The measured value with resolution 1 bit = 1/10°C is output signed in the signed amount presentation.
    Maximum presentation 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 = 0xFFFFhex = - 32767dec
    • 1000 0000 0000 0010bin = 0x8002hex = - 2dec
    • 1000 0000 0000 0001bin = 0x8001hex = - 1dec
    • 0000 0000 0000 0001bin = 0x0001hex = +1dec
    • 0000 0000 0000 0010bin = 0x0002hex = +2dec
    • 0111 1111 1111 1111bin = 0x7FFFhex = +32767dec

Presentation note on the "Resistance measurement" operation mode

In "Resistance Measurement" mode, the measured value is always displayed unsigned, irrespective of the "Presentation" setting (object 0x80n00:02), as 0..0xFFFF with the respective value.

1/16 Ω -> ~62 mΩ/digit

1/64 Ω -> ~15 mΩ/digit