Daytronic Corporation - 5D Series DC Strain Gage Conditioner Module

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DC Strain Gage Conditioner Module

Model 5D70 / 5D70V

The Models 5D70 and 5D70V are general-purpose single-channel conditioners for input of pressure, force, torque, weight, and other variables measured by conventional DC-excited strain gage transducers.

The 5D70 delivers filtered analog output of ą5 VDC, while the 5D70V produces ą10 VDC.

For both models, advanced analog design directly addresses the problem of measurement inaccuracy in industrial environments of high electromechanical noise. Exceptional signal stability and accuracy over a remarkably wide range of sensor inputs are achieved through

	remotely sensed excitation, user-selectable
	chopper-stabilized low-drift amplification
	configurable low-pass active filtering
	"absolute" and "two-point" software-based calibration
	effective signal isolation and ESD protection.

For both the Model 5D70V and the Model 5D70S (the "S" Option version of the Model 5D70), a 10-pin header for a Phoenix Style screw-terminal connector replaces the Model 5D70's standard DB25 connector for the module's power, configuration, logic, and analog output wiring. Ensuring secure cable connections to individual 5D modules, these versions are intended primarily for single-point or single-mount module applications. Since the logic "enable" line is not provided in this case, both analog outputs are continuously available for both the 5D70V and the 5D70S.

View / download complete
Model 5D70/5D70V Instruction Manual

The 5D70/5D70V Overcomes Errors That Traditionally Plague the Strain-Gage Measurement Process

For steady indication and smooth, dependable control action, the 5D70(V) can provide a true average value of the measured variable, even in the face of substantial dynamic content. As with most 5D Series modules, two high-level, noise-free analog output signals are provided. For the 5D70 (only), one output may be switched on and off by setting the logic state of an "enable" line. For the 5D70V, both outputs are continuously available.

Both models feature

	Powerful low-pass active filtering, independently selectable for each output, for removal of unwanted high-frequency measurement-signal components and the elimination of aliasing errors, if the module's output is subsequently sampled
	Selectable excitation using remote sensing of bridge voltage and slaved to an extremely stable reference voltage
	Input impedance in excess of 10,000 MΩ is presented to signal leads to eliminate cable resistance as a source of error (allowable cable length has virtually no practical limits)
	High noise rejection, eliminating errors from common-mode pickup and ground-loop coupling, with 1500 VAC isolation between input and output terminals and between I/O and power supply / communications terminals
	High ESD immunity and extensive EMI protection further assure data integrity in harsh industrial environments

Internal "Absolute" Calibration Ensures High Accuracies, Without Elaborate Trial and Error Procedures

To calibrate a 5D70(V), no "deadweighting" is required; you need only use the Configurator software provided with the unit to specify the desired relationship between the module's measured engineering units and its ą5-VDC or ą10-VDC output, given the full-scale input range for which it is currently set and the strain gage transducer's known full-scale rating and sensitivity. A zero offset term may also be entered, expressed either in engineering units or millivolts.

Conventional "two-point (deadweight)" calibration may be applied, if desired, to improve on the "absolute" calculations, when there are at least two independently and accurately known calibration points ("ZERO" and "SPAN"). Activation of a user-supplied shunt calibration resistor is provided (for either a positive or negative upscale reading) for use in the two-point method, if desired. Internal symmetry trimming is also available for negative slope adjustments of up to ą2% of full scale.

Guaranteed "absolute" calibration accuracies for a properly configured 5D70(V)'s input ranges and excitation levels are given in the Specifications, below. By virtue of the unusually high stability of the 5D70(V) instrument, even higher accuracies can be achieved with additional software-based "two-point" calibration.

Model 5D70(V) Specifications [Top

]

(Click here for 5D Series General Specifications)

Transducer Types

Conventional 4-arm strain gage bridges, 120 Ω to 10 kΩ; zero range is 20% of the stated full scale. A screw terminal is provided for user-supplied shunt calibration resistor. The diagrams below show standard 4-wire cabling (for under 20 ft. in length) and 8-wire cabling (for 20 ft. or longer).

Input Ranges (Nominal, Full-Scale) and Accuracy per Excitation Setting

See table, below; selectable when the 5D70(V) is configured. Accuracy is given as % of full-scale overall expected maximum error, following calibration. Note that the highest range selection accommodates actual inputs as high as 25 mV/V.

ALSO NOTE: The first five ranges in the list apply only when the 5D70(V) is set to an excitation of 10 VDC, and are not available for earlier 5D70 modules.

	Excitation
Range (mV/V)	2 VDC	5 VDC	10 VDC
0.10			0.25
0.15			0.20
0.20			0.15
0.25			0.10
0.375			0.06
0.50	0.25	0.15	0.05
0.75	0.20	0.10	0.04
1.00	0.15	0.05	0.02
1.50	0.10	0.03	0.02
2.00	0.05	0.02	0.02
3.00	0.03	0.02	0.02
4.00	0.02	0.02	0.02
6.00	0.02	0.02	0.02
8.00	0.02	0.02	0.02
12.00	0.02	0.02	0.02
16.00	0.02	0.02	0.02

Excitation

Nominal 2.00 VDC @ 50 mA, 5.00 VDC @ 60 mA, or 10.00 VDC @ 90 mA; selectable when the 5D70(V) is configured

Accuracy

Dependent on range and excitation; see table, above

Amplifier

Common-Mode Range

ą1 V operating**

Common-Mode Rejection Ratio (at 1 V of Common Mode)

-100 dB at DC; -120 dB at 60 Hz**

Input Impedance (Differential and Common-Mode)

Greater than 10,000 MΩ

Offset

Initial: ą4 μV
Vs. temperature: ą0.10 μV/°C
Vs. time: ą10 ppm/month

Gain Accuracy

ą0.02% of full scale typical, following calibration; see table, above

Gain Stability

Vs. temperature: ą25 ppm/°C
Vs. time: ą10 ppm/month

Analog Filters

0.2, 2, 20, 200, or 2000 Hz, independently selectable for each output

Analog Outputs

Filtered ą 0 to 5 VDC (for the Models 5D70 and 5D70S) or ą 0 to 10 VDC (for the Model 5D70V), with linearity maintained for 20% overrange. For the Model 5D70 (only), Output B is switchable via logic "Enable" line.

Logic-Input Functions
(see also General 5D Specs)

Enable, Not Calibrate A, Not Calibrate B
The following diagrams show 5D70 logic input connections for switch closure (no external supply) and active TTL logic, respectively, using the standard module DB25 connector. For the "Enable" function, see 5D Analog Outputs and the description of the MODULE IDENTIFICATION (MID) command.

NOTE: For the Models 5D70V and 5D70S, the Enable function is not provided, and both analog outputs are continuously available.

** With respect to bridge center (midpoint of excitation)

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