Measurement SG 1/4 bridge (quarter bridge) 120 Ω 2/3-wire connection

To determine the measuring error:

The transition resistance values of the terminal contacts affect the measurement. The measuring error can be reduced further through compensation by the user, with active signal connection.

The temperature coefficient (Terminal) can be significantly improved through an external, more temperature-stable auxiliary resistor and the terminal in half/full bridge operation.

Quarter bridge calculation:

Measurement SG 1/4 bridge (quarter bridge) 120 Ω 2/3-wire connection 1:

R2/3/4 are the internal switchable input resistors of the terminal.

The strain relationship (µStrain, µε) is as follows:

Measurement SG 1/4 bridge (quarter bridge) 120 Ω 2/3-wire connection 2:

For the quarter bridge, N=1 always applies.

Note: specifications apply for 2.5 V SG excitation.

Measurement mode

SG 1/4 bridge 120 Ω

Measuring range, nominal

120 ± 12 Ω or ±25 mV/V

[corresponds to 108 Ω…132 Ω]

[corresponds to ±50000 µε at K=2]

Measuring range, end value (full scale value)

132 Ω

Measuring range, technically usable

120 ± 12.88.. Ω

PDO resolution

24 bit (including sign)

PDO LSB (Extended Range)

1.536 µΩ/Step

PDO LSB (Legacy Range)

1.430.. µΩ/Step

Basic accuracy: Measuring deviation at 23°C, with averaging (2

2-wire connection: 0.05% typ. (relative to full scale value)

3-wire connection: 0.04% typ. (relative to full scale value)

4-wire connection: not possible

Integrated power supply

0.5…2.5 V adjustable, max. supply/excitation 21 mA (internal electronic overload protection)

Temperature coefficient (¹

TcTerminal

<8 ppm/K typ.
(rel. to full scale value, from HW Version 06; refer to serial number)

<12 ppm/K typ.

(rel. to full scale value, HW Version 04, since production 2016 week 10; refer to serial number)

<60 ppm/K typ.
(rel. to full scale value, HW Version 01-04, production until 2016 week 09; refer to serial number)

¹) Please see the remarks to 2/3/4 wire measurement within section for resistance measurement of section “technical data”.

2) Dominant part of the basic accuracy is its offset specification (see following tables). The process described in the Offset correction section eliminates this proportion and increases the measurement accuracy considerably.

Measurement mode

SG 1/4 bridge 120 Ω (2 wire)

Offset/Zero Point deviation (at 23°C)

EOffset

< 420 [ppmFSV]

Gain/scale/amplification deviation (at 23°C)

EGain

< 250 [ppm]

Non-linearity over the whole measuring range

ELin

< 50 [ppmFSV]

Repeatability (at 23°C)

ERep

< 15 [ppmFSV]

Noise (without filtering, at 23°C)

ENoise, PtP

< 160 [ppmFSV]

< 13750 [digits]

ENoise, RMS

< 20 [ppmFSV]

< 1720 [digits]

Max. SNR

> 73.1 [dB]

Noisedensity @1kHz

< 37.36 Measurement SG 1/4 bridge (quarter bridge) 120 Ω 2/3-wire connection 3:

Noise (with 50 Hz FIR filtering, at 23°C)

ENoise, PtP

< 6 [ppmFSV]

< 520 [digits]

ENoise, RMS

< 1 [ppmFSV]

< 86 [digits]

Max. SNR

> 99.2 [dB]

Common-mode rejection ratio (without filtering)3

DC:
< 0.3 Ω/V
typ.

50 Hz:
< 1 Ω/V
typ.

1 kHz:
< 20 Ω/V
typ.

Common-mode rejection ratio (with 50 Hz FIR filtering)3

DC:
< 300 mΩ/V
typ.

50 Hz:
< 40 mΩ/V
typ.

1 kHz:
< 0.5 mΩ/V
typ.

Largest short-term deviation during a specified electrical interference test

±1%FSV typ.

3) Values related to a common mode interference between SGND and internal ground.

Measurement mode

SG 1/4 bridge 120 Ω (3 wire)

Offset/Zero Point deviation (at 23°C)

EOffset

< 360 [ppmFSV]

Gain/scale/amplification deviation (at 23°C)

EGain

< 150 [ppm]

Non-linearity over the whole measuring range

ELin

< 50 [ppmFSV]

Repeatability (at 23°C)

ERep

< 15 [ppmFSV]

Noise (without filtering, at 23°C)

ENoise, PtP

< 160 [ppmFSV]

< 13750 [digits]

ENoise, RMS

< 20 [ppmFSV]

< 1720 [digits]

Max. SNR

> 73.1 [dB]

Noisedensity @1kHz

< 37.36 Measurement SG 1/4 bridge (quarter bridge) 120 Ω 2/3-wire connection 4:

Noise (with 50 Hz FIR filtering, at 23°C)

ENoise, PtP

< 6 [ppmFSV]

< 520 [digits]

ENoise, RMS

< 1 [ppmFSV]

< 86 [digits]

Max. SNR

> 99.2 [dB]

Common-mode rejection ratio (without filtering)3

DC:
< 0.3 Ω/V
typ.

50 Hz:
< 1 Ω/V
typ.

1 kHz:
< 20 Ω/V
typ.

Common-mode rejection ratio (with 50 Hz FIR filtering)3

DC:
< 300 mΩ/V
typ.

50 Hz:
< 40 mΩ/V
typ.

1 kHz:
< 0.5 mΩ/V
typ.

Largest short-term deviation during a specified electrical interference test

±1%FSV typ.

3) Values related to a common mode interference between SGND and internal ground.

The channel value (PDO) can be interpolated in ±12 Ω or ±25 mV/V:

Measurement SG 1/4 bridge (quarter bridge) 120 Ω 2/3-wire connection 5:
Representation measuring range SG 1/4 bridge 120 Ω