1 Operating principle

When the metal material is subjected to tension or strain, the metal material becomes thinner and the electrical impedance increases. On the contrary, when it is compressed, the metal impedance becomes smaller. Applying this method to make a strain gauge is called a weighing module. Such sensing devices can convert pressure in physical phenomena into electrical signal output, so they are often used in applications where load, tension, and pressure are converted.

2 Introduction

1. Thank you for using the Wecon LX3V-2WT-G module. This module is compatible with all the functions of the LX3V-2WT module, and adds the function of flow calculation, which is dedicated to the grammage system. The weighing module LX3V-2WT-G provides 24-bit high resolution and can be applied to various eigenvalue weighing modules of 4 or 6-wire type. The response speed can be adjusted according to the needs of customers, and it can easily meet the current load application market. comprehensive needs.
2. In order to ensure the correct installation and operation of this product, please read the manual carefully before using the module. This manual is only for LX3V-2WT-G operation guide and reference.
3. The LX3V-2WT-G weighing module can read and write data with the instruction FROM/TO through LX3V or LX5V.

Specifications

Valid bits

For details, please refer to "(4) BFM3: Sampling frequency" in "BFM description" in "Chapter 5" of this manual.

3. Appearance and size

Dimensions

1. Expansion cable
2. COM light: Module internal data communication indicator
3. 24V light: Always on when connected to external DC24V power supply
4. WT light: Channel input/output indicators; WE light: Channel calibration indicator
5. LINK: Communication indicator between PLC and module
6. Name of the expansion module
7. Expansion module interface
8. DIN rail mounting clip
9. Hook for DIN rail
10. Holes for direct mounting: 2 places (φ4.5)

Use of blade terminals

Use crimp terminals of the size shown in the figure. Terminal tightening torque is 0.5 to 0.8N.m. Be sure to tighten the screws so as not to cause malfunction.

Terminals

4 Wiring

✎Note:

• The impedance of the load cell is greater than 200Ω.
• The four-wire sensor requires E1+ to be connected to F1+, E1 to be connected to F1-.

5 Buffer Register (BFM)

BFM list

✎Note: Symbol Description

1. O means retentive type.
2. X means non-retentive type.
3. R means readable data.
4. W means writable data.

BFM description

BFM0: Module model code

The model code for the LX3V-2WT-G module is 5016.

BFM1: Software version

The software version is displayed in decimal, which is used to indicate the software version of the expansion module.

BFM2: Unipolar

Bipolar means that the signal passes through zero in the process of changing, and unipolar does not pass zero. Since the conversion of analog quantity to digital quantity is a signed integer, the value corresponding to the bipolar signal will have a negative number.

BFM3: Sampling frequency

The module collects the frequency of the input signal. The lower the frequency, the more stable the value and the higher the accuracy, but the rate is reduced. The setting value corresponds to the sampling frequency as follows:

BFM4: Status code

BFM5: Error code

Tare setting: CH1-BFM6, CH2-BFM46

Writing 1 to CH1-BFM6/CH2-BFM46 is valid; after execution, reset to 0. Select the current weight value (BFM16-17) as the weight value for the tare weight (BFM19-20). Takes CH1 as an example.

The current weight value is 100, after tare setting:

• If the gross weight is currently displayed (BFM7=0), the tare weight (BFM19-20) becomes 100, and the current weight is still 100;
• If the net weight is currently displayed (BFM7=1), the tare weight (BFM19-20) It becomes the original value + the current weight value, and the current weight value becomes 0.

BFM8: Weight calibration instruction

Adjustment steps: (Described with CH1)

• Calibration with weights
  • Step1: Do not put any weights on the load cell.
  • Step2: Write 0x0001 to #8.
  • Step3: Add standard weights to the load cell.
  • Step4: Write the weight of the current weight on the chassis into #23.
  • Step5: Write 0x0002 to #8.
• Weightless calibration
  • Step1: Do not put any weights on the load cell.
  • Step2: Write the maximum range of the sensor into #23.
  • Step3: Write the sensor sensitivity into #39, accurate to three decimal places.
  • Step4: Write 0x0003 to #8.
• Modify calibration parameters:
  • Step1: Modify the calibration parameter values in BFM#35 to BFM#38;
  • Step2: Write 0x0004 to #8.

BFM11: Filter strength

The greater the filter strength, the more stable and accurate the weight value will be, but the delay will increase and the sensitivity will decrease accordingly, which can be set as required.

BFM12: Zero tracking interval time

BFM#12 is used in conjunction with BFM#13. When BFM#13 is not 0, BFM#12 indicates the interval between the current automatic weight reset and the next automatic reset to prevent continuous reset.

BFM13: Zero tracking range

The accumulation range of zero point tracking. If the accumulation exceeds this range, the tracking will not continue.

E.g: The setting value is 100, after the zero point drifts from the 0 position to more than ±100, the tracking will not continue. If it drifts back to within ±100, the tracking will be resumed.

BFM15: Set the AD chip gain

It can be set according to the sensor range. After the BFM is set, it needs to be re-calibrated.

Function description

Net weight measurement function

You could choose whether the measured weight is net weight or gross weight. Net weight refers to the weight of the product itself, that is, the actual weight of the product after removing the weight of the outer packaging. The weight of the outer packaging is generally called the tare weight, and the gross weight is the total weight, which refers to net weight plus tare weight.

• Tare weight: Refers to the weight of the outer packaging.
• Net weight: Refers to the weight of the product itself, that is, the actual weight of the product after removing the weight of the outer packaging.
• Gross weight: Refers to the total weight, that is, the weight of the product itself (net weight), plus the weight of the outer packaging (tare weight)
• Gross weight = net weight + tare weight.

E.g: There is a product that is 10KG, the carton it is packed in weighs 0.2KG, and the total weight is 10.2KG.

• Net weight=10KG
• Tare weight=0.2KG
• Gross weight=10.2KG

E.g: Use CH1 to measure the value to display the net weight, and CH2 to select OFF. (If the weight of the outer package is known, you can skip the step of reading the tare weight).

• Read the tare value
  • Write H0000 in BFM7;
  • Place the package on the CH1 weighing module;
  • Write H0001 in BFM6, and take the current package weight as the tare weight.
• Set BFM7=H0001

Stability check

When placing the item on the weighing module to measure the weight, the user can use the stability check function to know that the current measurement value is stable.

• If the variation range of the measured value is within the stable range #22 set by the user, the #4 stable bit of the measured value will be set to 1.
• When the variation range of the measured value exceeds the set stability range, the #4 stable bit of the measured value will be set to 0, until the stability check time #21 is within the stable range, the #4 stable bit of the measured value will be set to 1 again.

E.g: The stability check time is set to 200ms, and the stability check range is 10. When the change range exceeds 10, the measurement value is unstable, that is, the #4 stable bit of the measured value will be set to 0. When the beating range is within 10 within 200ms, the stable bit of the measurement value will be set to 1 again. (It is recommended that the user should judge whether the current measurement value is stable before performing control).

Zero point judgment

You could use the zero point judgment function to know that the item has been removed from the weighing module. You could judge that the measurement value is stable and the Bit is 1, which means that the item has been removed from the weighing module, and you could perform the next step at this time. (The zero point weight Bit in the zero point judgment range is 1).

Filter function

The average value is the function of summing and averaging the read values to obtain a slowing value, but the environment used will have unavoidable external force factors, which will cause the read value to have a sharp change in the surge value. The change also becomes larger. The function of filtering is not to include the sharply changing surge value in the aggregated average, and the obtained filtered average value will not be affected by the sharply changed surge value.

Standard of g/m

• Fast Track Criteria:
  • After 20 seconds, the error between the flow rate and the final value is within 5% (the final value is the flow rate value at 20 minutes)
• Final value accuracy standard:
  • If the flow is above 1000: After 20 minutes, the error between the flow rate and the final value is within 0.5% (The final value is the average of several final values)
  • If the flow is below 1000: After 20 minutes, the error between the flow rate and the final value is within 1% (The final value is the average of several final values

6 Example

Get the current weighing status

 Read the current weighing state BFM4 and judge it by Bit state. For details, please refer to the description of BFM4 in "5.2 Buffer Register Description".

Get the current weighing value

Write the average weight value (BFM16) of CH1 in the weighing module into D0.

Calibration weight

* In the new version, the first step can also be used for manual reset.

The adjustment is to make the module match the weight value of the load cell of the weighing module. The adjustment steps are as follows. Described with CH1.

Tare and gross weight

Filter mode setting

After setting the filter method or filter strength, re-calibration is required.

Zero tracking

Zero tracking is used to reduce temperature drift interference.

The zero tracking range is 0, which means zero tracking is not enabled.

Calibration without weights

The calibration without weights is calibrated by the zero point of the sensor and the maximum range of the sensor. The accuracy is related to the sensor specification and depends on the sensitivity of the sensor (mV/V).

For example: The sensitivity of the LAB-B-B sensor is 2.0±10%mV/V, and there may be a maximum error of 10%. Therefore, it is best to use a sensor with a small sensor sensitivity error when using this function.

Modify calibration parameters

✎Note: BFM35, BFM36, BFM37, and BFM38 are real numbers (float). When inputting, you need to input real numbers. If the input exceeds the range, BFM5 will report an error in writing calibration parameters.

7 Diagnosis

Check

1. I. Check that the input wiring and/or extension cables are properly connected to the LX3V-2WT-G analog special function module.
2. II. Check that the LX3V system configuration rules are not violated. E.g: The number of special function modules cannot exceed 8, and the total number of system I/O points cannot exceed 256 points.
3. Ⅲ. Make sure the correct operating range is selected in the application.
4. IV. Check that there is no power overload on the 5V or 24V power supply, remember: the load of the LX3V main unit or active expansion unit varies according to the number of connected modules or special function modules.
5. V. Set the LX3V unit in RUN state.

Check errors

If the special function module LX3V-2WT-G does not operate normally, please check the following items.

• Check the status of the LINK indicator
  • Blink: Expansion cables are properly connected.
  • Otherwise: Check the connection of the extension cable.
• Check the status of the "24V" LED indicator (top right corner of the LX3V-2WT-G)
  • Light on LX3V-2WT-G is normal, and 24VDC power is normal.
  • Otherwise: 24V DC power supply may be faulty. If the power supply is normal then the LX3V-2WT-G is faulty.
• Check the status of the "COM" LED indicator (top right corner of the LX3V-2WT-G)
  • Blink: Numeric conversion works fine.
  • Otherwise: Check buffer memory #5 (error status).

If any of the bits (b0, b1, b2) are ON, that's why the COM indicator is off. For details, please refer to "(6) BFM5: Error Code" in "5.2 Buffer Register (BFM) Description" in "Chapter 5" of this manual.

• Check the sensor, measure whether the voltage between S+ and S- is less than (5*sensor sensitivity) mv, the sensor sensitivity is found in the sensor manual used, the unit is (mv/v), if the voltage at this point is out of range, it means the sensor Deformation or wiring errors have occurred. Measure whether the voltage between F+ and F- is 5V, if not, check the sensor wiring.