VGVGV LM8-RRD Digital Weighing Controller User Manual

1. Introduction

This manual provides detailed instructions for the installation, operation, and maintenance of the VGVGV LM8-RRD Digital Weighing Controller. This device is designed to work with various pressure and weight sensors, specifically 1-4 load cells, providing precise weight control and display for applications such as DIY portable electronic kitchen scales.

2. Safety Information

• Ensure the power supply matches the controller's requirements (AC 220V or 110V as indicated on the unit).
• All wiring should be performed by qualified personnel to prevent electrical shock or damage to the device.
• Do not operate the controller in environments with excessive moisture, dust, or corrosive gases.
• Disconnect power before performing any maintenance or wiring changes.
• Avoid physical impact or dropping the device.

3. Package Contents

Upon opening the package, please verify that all items are present and undamaged:

• 1 x VGVGV LM8-RRD Digital Weighing Controller
• 2 x Mounting Brackets
• 1 x User Manual (this document)

Figure 3.1: Package contents including the controller, brackets, and manual.

4. Product Overview

The LM8-RRD Digital Weighing Controller features a dual LED nixie tube display for clear reading of process value (PV) and set value (SV). It supports input from 1-4 load cells and provides 2 relay outputs for control applications. The instrument also includes data/peak value holding and functions for clearing zero and PV modification.

4.1. Front Panel and Display

Figure 4.1: Front panel of the weighing controller.

• PV (Process Value) Display: Large LED display showing the current weight or measured value.
• SV (Set Value) Display: Smaller LED display showing the setpoint or parameter value.
• AL1/AL2 Indicators: LEDs indicating the status of Relay Output 1 and 2.
• OUT Indicator: LED indicating the general output status.
• Buttons: SET, RST (Reset/Shift), Up, Down for navigation and parameter adjustment.

4.2. Rear Panel and Wiring Terminals

Figure 4.2: Rear panel with wiring diagram.

The rear panel provides clearly labeled terminals for power input, load cell connections, and relay outputs. Refer to Section 5.2 for detailed wiring instructions.

5. Setup

5.1. Installation

The controller is designed for panel mounting. The dimensions are 48mm x 48mm x 80mm. A hole size of 45mm x 91mm is required for proper installation. Use the provided mounting brackets to secure the controller firmly into the panel cutout.

5.2. Wiring

Carefully connect all wires according to the diagram on the rear panel and the instructions below. Ensure power is disconnected before making any connections.

Figure 5.1: Detailed view of the wiring terminal block.

1. Power Input (AC 220V / 110V): Connect your main power supply to the terminals labeled 'AC 220V' or '110V' and 'N' (Neutral) and 'L' (Live). Ensure correct voltage is applied.
2. Relay Outputs (AL1, AL2, COM): The controller provides 2 relay outputs. Connect your external control devices (e.g., alarms, motors) to the 'AL1', 'AL2', and 'COM' (Common) terminals as required by your application.
3. Load Cell Input (EXC5V, SG-, SG+, V-):
   • EXC5V: Excitation voltage output (DC 5V) for load cells.
   • SG- (Sense Ground): Signal ground for load cell.
   • SG+ (Sense Plus): Signal input from load cell.
   • V- (Voltage Minus): Negative voltage input for load cell.

   The instrument provides isolated auxiliary power (regularly 5V 80mA) which allows direct connection of 1-4 load cells. Connect the load cell wires (Excitation+, Excitation-, Signal+, Signal-) to the corresponding terminals. Refer to your load cell's specific wiring diagram for correct connections.

4. RST (Reset): Connect to an external reset button if desired.

6. Operating Instructions

After successful installation and wiring, power on the device. The LED display will illuminate.

6.1. Basic Display Information

• PV Display: Shows the current measured weight or value from the load cell(s).
• SV Display: Shows the setpoint or parameter value during configuration.
• AL1/AL2/OUT Indicators: Light up when the corresponding relay output is active.

6.2. Button Functions

• SET Button: Used to enter parameter setting mode and confirm selections.
• RST (Reset/Shift) Button: Used to clear the current value (zeroing) or to shift digits during parameter entry.
• Up (▲) Button: Used to increase parameter values or navigate through menus.
• Down (▼) Button: Used to decrease parameter values or navigate through menus.

6.3. Zeroing the Scale

To clear the current weight and set the display to zero, press the RST button. This is typically done when there is no load on the scale to establish a baseline.

6.4. Parameter Setting (Calibration and Setpoints)

The controller allows for calibration and setting of various parameters such as alarm setpoints, data holding functions, and PV modification. The exact procedure for calibration and parameter setting will depend on the specific application and load cell used. Generally, this involves:

1. Press and hold the SET button to enter the parameter setting mode.
2. Use the Up and Down buttons to navigate through different parameters.
3. Press SET again to select a parameter for editing.
4. Use Up, Down, and RST (for shifting digits) to adjust the value.
5. Press SET to confirm the new value and move to the next parameter or exit the setting mode.

Refer to the detailed parameter list in the included physical user manual for specific codes and their functions.

7. Maintenance

• Cleaning: Use a soft, dry cloth to clean the display and casing. Do not use abrasive cleaners or solvents.
• Inspection: Periodically check all wiring connections for tightness and signs of wear or damage.
• Environment: Ensure the operating environment remains within specified temperature and humidity ranges to prolong the life of the device.

8. Troubleshooting

If you encounter issues with your VGVGV LM8-RRD Digital Weighing Controller, consider the following common problems and solutions:

• No Display/Power:
  • Check power connections and ensure the correct voltage is supplied.
  • Verify the power source is active.
• Incorrect Weight Reading:
  • Ensure load cell wiring is correct and secure.
  • Perform a zeroing operation (press RST).
  • Recalibrate the controller with known weights.
  • Check the load cell for damage or malfunction.
• Relay Outputs Not Activating:
  • Verify the setpoints (SV) are correctly configured.
  • Check the wiring to the external control devices.
  • Ensure the PV is reaching the setpoint to trigger the relay.
• Unstable Readings:
  • Check for electromagnetic interference (EMI) from nearby equipment.
  • Ensure the load cell and its mounting are stable and free from vibrations.
  • Verify load cell connections are tight and free from corrosion.

If problems persist, contact VGVGV customer support for further assistance.

9. Specifications

10. Warranty and Support

The VGVGV LM8-RRD Digital Weighing Controller comes with a standard manufacturer's warranty. For specific warranty terms, conditions, or technical support, please refer to the warranty card included with your product or contact VGVGV customer service directly through their official channels.