Difference between revisions of "Component: Load Cell (HX711) (Force)"
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The HX711 load cell amplifier is used to get measurable data out from a load cell or strain gauge. | The HX711 load cell amplifier is used to get measurable data out from a load cell or strain gauge. | ||
| − | ==Component | + | ==Component Source Code== |
| − | + | Please click here for the component source code: [https://www.flowcode.co.uk/wikicopy/componentsource/FC_Comp_Source_HX711.fcfx FC_Comp_Source_HX711.fcfx] | |
==Detailed description== | ==Detailed description== | ||
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==Examples== | ==Examples== | ||
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| width="10%" align="center" style="border-top: 2px solid #000;" | [[File:Fc9-s32-icon.png]] - LONG | | width="10%" align="center" style="border-top: 2px solid #000;" | [[File:Fc9-s32-icon.png]] - LONG | ||
| + | | width="90%" style="border-top: 2px solid #000;" | ''Return'' | ||
| + | |} | ||
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| + | {| class="wikitable" style="width:60%; background-color:#FFFFFF;" | ||
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| + | | width="10%" align="center" style="background-color:#D8C9D8;" align="center" | [[File:Fc9-comp-macro.png]] | ||
| + | | width="90%" style="background-color:#D8C9D8; color:#4B008D;" | '''SetChannelAndGain''' | ||
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| + | | colspan="2" | Allows the preselected input channel and gain to be overridden. | ||
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| + | | width="10%" align="center" | [[File:Fc9-bool-icon.png]] - BOOL | ||
| + | | width="90%" | Channel | ||
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| + | | colspan="2" | Range: 0-1 / 0=A 1=B | ||
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| + | | width="10%" align="center" | [[File:Fc9-u8-icon.png]] - BYTE | ||
| + | | width="90%" | Gain | ||
| + | |- | ||
| + | | colspan="2" | Channel A can be 128 or 64, Channel B can be 32 | ||
| + | |- | ||
| + | | width="10%" align="center" style="border-top: 2px solid #000;" | [[File:Fc9-void-icon.png]] - VOID | ||
| width="90%" style="border-top: 2px solid #000;" | ''Return'' | | width="90%" style="border-top: 2px solid #000;" | ''Return'' | ||
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Revision as of 17:47, 9 November 2022
| Author | Matrix TSL |
| Version | 2.0 |
| Category | Force |
Contents
Load Cell component
The HX711 load cell amplifier is used to get measurable data out from a load cell or strain gauge.
Component Source Code
Please click here for the component source code: FC_Comp_Source_HX711.fcfx
Detailed description
No detailed description exists yet for this component
Examples
A simple example showing how to get a meaningful reading out of the HX711 IC connected to a load cell sensor. Zeros/Tares the reading when the switch is pressed.
The scale factor was determined by performing calibration with a unity scale of 1.0 and fixed weight weights. A table of weight vs reading was constructed to provide the correct scale factor.
Here is a guide to calibrate your sensor
When 0g was present on the load cell we zero the output.
When 10g was present on the load cell we get a reading of approx 2170.
2170 / 10g = 217 per g.
When 20g was present on the load cell we get a reading of approx 4340.
4340 / 20g = 217 per g.
1 / 217 = Scale Factor of 0.004608
The readings may not be 100% linear so it's best to take several samples based on different weights across the range you want to be able to measure and from this you can work out a close fitting average.
Downloadable macro reference
|
SetScaling |
| Sets the scaler for the samples to provide a meanningful value. Default scaler is set to 1.0 | |
 - FLOAT
|
Scaler |
| Unity Scale = 1.0 | |
 - VOID
|
Return |
|
|
ScaledSample |
| Takes a raw sample and then applies the scaling factor to return a real world value. | |
| - FLOAT
|
Return |
|
|
Zero |
| Zeros the reading at the current sample | |
| - VOID
|
Return |
|
|
RawSample |
| Allows the HX711 to be directly read returning the raw unscaled 24-bit reading. Reading is relative to the last defined Zero point. If a timeout occurs and the HX711 is not ready then we return the last valid reading. | |
 - LONG
|
Return |
|
|
SetChannelAndGain |
| Allows the preselected input channel and gain to be overridden. | |
 - BOOL
|
Channel |
| Range: 0-1 / 0=A 1=B | |
 - BYTE
|
Gain |
| Channel A can be 128 or 64, Channel B can be 32 | |
| - VOID
|
Return |
|
|
SetSampleCount |
| Specifies the number of samples to perform when taking a reading. The more samples the more filtered the signal will become from high frequency noise. | |
| - BYTE
|
NumSamples |
| Default 1. Range 1-20 | |
 - UINT
|
Delay |
| Time to wait between samples in milliseconds. | |
| - VOID
|
Return |
|
|
Initialise |
| Sets up the I/O ready for communications with the HX711 IC and performs an initial sample to set the channel and gain. Must be called before calling other HX711 component macros. | |
| - VOID
|
Return |
Property reference
|
Properties |
|
Input Channel |
| Selects which channel to sample A or B. Gain settings are channel specific. A Gain can be 128x or 64x B Gain is fixed at 32x | |
|
|
Input Gain |
| Gain settings are channel specific. A Gain can be 128x or 64x B Gain is fixed at 32x | |
|
Data |
| Data pin - connected to HX711 Data Out pin. | |
|
|
Clock |
| Clock pin - connected to HX711 SCK pin. | |
|
Clock Transition Delay |
| Number of microseconds to wait after each clock edge. Max theoretical: 10Hz Mode = 1uS / 80 Hz Mode = 4uS | |
|
Use Median Filter |
