1. Introduction
The LiebeWH 4-20mA Signal Generator is a precision instrument designed for simulating 4-20mA process signals. It is an essential tool for calibrating and testing various industrial control devices, including PLC analog inputs, transmitters, and actuators. This generator features a digital display for accurate output readings and incorporates built-in protection circuits for safe operation in diverse industrial environments.
- Precise Current Simulation: Provides an adjustable output from 0 to 22mA with a digital display for accurate signal simulation.
- PLC and Instrument Calibration: Ideal for calibrating and testing PLC analog inputs, transmitters, actuators, and other industrial control devices.
- Short Circuit Protection: Integrated protection circuits safeguard the generator against accidental short circuits, ensuring reliable field use.
- Compact DIN Rail Mount: Its compact size and DIN rail compatible design allow for easy permanent installation in control cabinets.
- Stable Anti-Interference Output: Engineered for stable output even in electrically noisy industrial environments, ensuring reliable test results.
2. Product Overview
The 4-20mA Signal Generator is housed in a durable white ABS casing, designed for DIN rail mounting. It features a digital display, an adjustment knob, and clearly labeled terminal blocks for power and signal connections.
Figure 2.1: Front view of the signal generator, highlighting the digital display and the rotary adjustment knob for current output.
Figure 2.2: Side view illustrating the integrated DIN rail mounting clip for easy installation.
Figure 2.3: Top view displaying the clearly labeled terminal blocks for input power and signal output connections.
3. Specifications
| Parameter | Value |
|---|---|
| Voltage Supply Range | DC 15V - DC 28V |
| Power Consumption | <2W |
| Current Output Range | 0mA - 22mA (adjustable, 4-20mA in default) |
| Output Adjustment Accuracy | 0.1mA |
| Output Error | <0.05mA |
| Load Sampling Resistance | <500 ohms |
| Working Environment Temperature | 0-40℃ |
| Relative Humidity | <80% |
| Material | ABS |
| Item Weight | 122 Grams |
| Special Feature | Short Circuit Protection |
Figure 3.1: Product dimensions, showing length, width, and height in both millimeters and inches.
4. Setup and Installation
The signal generator is designed for easy installation onto a standard DIN rail. Ensure the power supply is disconnected before proceeding with installation and wiring.
4.1 DIN Rail Mounting
To mount the device, align the integrated clip on the back of the generator with the DIN rail. Press firmly until it clicks into place. To remove, pull the red release tab and lift the device off the rail.
Figure 4.1: Detail of the DIN rail mounting clip and release mechanism.
4.2 Wiring Connections
Refer to the wiring terminal diagram below for correct connections. Use shielded and twisted pair cables for optimal anti-interference ability, especially in noisy industrial environments, to ensure stable transmission and communication.
Figure 4.2: Wiring Terminal Diagram and Description. This diagram illustrates connections for DC 24V power supply, AC 220V power supply (optional), and RS485 communication (optional).
- GND: Signal Output Ground
- OUT: Signal Output Positive
- VCC: DC Power Input Positive
- GND: DC Power Supply Input Ground (connected with signal ground)
- ACL: AC Power Supply L
- ACN: AC Power Supply N
- B-: RS485 Communication B-
- A+: RS485 Communication A+
Figure 4.3: The use of shielded and twisted pair cables is recommended for enhanced anti-interference capabilities, ensuring stable data transmission over long distances and with multiple connected devices.
5. Operating Instructions
Once the signal generator is correctly installed and powered, you can adjust the current output using the rotary knob on the front panel. The digital display will show the current output value in real-time.
5.1 Adjusting Output Current
- Power On: Ensure the device is powered within the specified DC 15V-28V range.
- Rotate Knob: Turn the rotary knob clockwise to increase the current output and counter-clockwise to decrease it.
- Monitor Display: Observe the digital display to set the desired current value between 0mA and 22mA. The default output range is 4-20mA.
Figure 5.1: Close-up view of the digital display and the rotary knob, indicating the direction for increasing (+) and decreasing (-) current output.
5.2 Operational Demonstration Video
Video 5.1: A short demonstration showing the physical handling of the signal generator and the adjustment of the output current using the rotary knob. This video provides a visual guide to the device's operation.
6. Safety Information
Always prioritize safety when working with electrical equipment. This device includes features to enhance safety during operation.
- Short Circuit Protection: The generator is equipped with internal circuits to protect against damage if the output is accidentally shorted.
- Reverse Protection: Designed with reverse polarity protection to prevent damage from incorrect power supply connections.
- Ensure all wiring is correct and secure before applying power.
- Do not exceed the specified voltage supply range (DC 15V-28V).
- Operate within the recommended working environment temperature (0-40℃) and humidity (<80%).
Figure 6.1: Visual representation of key safety features: short circuit protection and reverse protection.
7. Maintenance
The LiebeWH 4-20mA Signal Generator is designed for low maintenance. Regular cleaning and inspection are recommended to ensure optimal performance and longevity.
- Cleaning: Use a soft, dry cloth to clean the exterior of the device. Avoid using abrasive cleaners or solvents.
- Inspection: Periodically check all wiring connections to ensure they are secure and free from damage. Inspect the casing for any signs of physical damage.
- Storage: When not in use, store the device in a dry, dust-free environment within the specified operating temperature range.
8. Troubleshooting
If you encounter issues with your signal generator, consider the following basic troubleshooting steps:
- No Power/Display Off: Verify that the power supply is connected correctly and providing the specified DC 15V-28V. Check for loose connections.
- Incorrect Output: Ensure the rotary knob is adjusted to the desired value. Check the load resistance to ensure it is within the <500 ohms specification.
- Unstable Output: Confirm that shielded and twisted pair cables are used, especially in environments with electrical noise. Check for external interference sources.
- No Output: Check all wiring for continuity and correct polarity. Ensure the device is not in a short-circuit condition, which might trigger protection.
If problems persist after performing these checks, please contact customer support.
9. Warranty and Support
Specific warranty details for the LiebeWH 4-20mA Signal Generator are not provided in this manual. For information regarding warranty coverage, returns, or technical support, please refer to the product packaging, your purchase documentation, or contact the seller directly.