ProMax 420G-HM3 Adjustable 0-20mA 4-20mA Signal Generator Simulator

Specifications

• Signal Output Range: 0-20mA / 4-20mA adjustable
• Adjustment Resolution: 0.01mA (High Precision)
• Operating Voltage: 15V - 30V DC (Standard 24V industrial supply compatible)
• Display Interface: Clear backlit LCD for real-time mA reading
• Control Mechanism: High-accuracy rotary encoder dial (Push to click/select)
• Protection Circuitry: Built-in reverse polarity protection on power terminals
• Output Modes: Supports both Active output and Passive (2-wire) simulation 

Features

• 0.01mA error, high linearity output.
• Output range is switchable: 0-20mA, 4-20mA, 0-22mA, 0-24mA. Switching via knob.
• Using long life span encoder with step-less knob, can rotate and press it.
• Fine adjustment can be 0.01mA/pulse, rough adjustment can be 5mA/pulse.
• Programmable adjusting mode: rough adjustment or fine adjustment.
• LED display is settable among current signal value display, 0-100.0 percentage display, etc.
• Min. changing step can be 0.01mA (the last digit plus or minus 1).
• 4 digits 0.4 inch clear LED display, standard panel-mounted package.
• 4 Pin pluggable wiring terminal blocks, easy to do wire connection.
• Output has short-circuit protection functions.
• Have polarity reverse connection protection circuit in power supply terminals.
• Digital encoder used, long durability, strong anti-interference capability.

Applications

• Industrial Automation: Debugging and commissioning PLC and DCS analog input modules.
• Sensor Calibration: Simulating outputs from pressure, flow, and temperature (PT100/Thermocouple) transmitters.
• Motor Control: Injecting exact 4-20mA reference signals into VFDs (Variable Frequency Drives) to test speed control loops.
• Valve Positioning: Testing and calibrating electro-pneumatic proportional valves.

Package Includes:

• 1 x ProMax 420G-HM3 Adjustable 0-20mA 4-20mA Signal Generator Simulator

Frequently Asked Questions (Technical FAQs)

• How do I power the ProMax 420G-HM3 generator?
  It requires an external DC power supply ranging from 15V to 30V DC. A standard 24V industrial power supply is ideal.
• Can it simulate a 2-wire passive transmitter?
  Yes, the HM3 can be wired in series with a loop power supply to act as a passive 2-wire sensor simulator.
• Does it support active 4-wire analog outputs?
  Yes, when powered, it can actively drive a current signal out to a receiving device like a PLC.
• What is the output resolution of this simulator?
  The rotary encoder allows for precise adjustments down to 0.01mA.
• Can it output exactly 0mA instead of starting at 4mA?
  Yes, the output range covers the full 0-20mA spectrum, not just the 4-20mA band.
• Is it safe to connect directly to my PLC analog input channel?
  Yes, as long as the PLC is configured to accept a standard 0/4-20mA current signal.
• What happens if I accidentally reverse the power wires?
  The unit features built-in reverse polarity protection to prevent immediate destruction of the internal circuitry.
• Does it come with an internal rechargeable battery?
  No, this specific model requires continuous external DC power (15-30V) to operate.
• Can I use this to test a VFD (Variable Frequency Drive)?
  Absolutely, if your VFD accepts an analog 4-20mA signal for frequency/speed reference, this is the perfect tool to test it.
• What is the maximum load impedance it can drive?
  It depends on your supply voltage, but at 24V DC, it can comfortably drive typical 250-ohm or 500-ohm receiver impedances.
• How do I quickly adjust the current output?
  Turn the rotary encoder dial. Some models allow pushing the dial to switch between coarse and fine adjustment modes.
• Does the LCD screen show the exact real-time mA output?
  Yes, the backlit LCD provides a direct readout of the current being generated.
• Can it directly simulate a PT100 RTD sensor?
  No, it simulates the 4-20mA output from a PT100 transmitter, not the raw resistive ohms of the PT100 element itself.
• Is it suitable for calibrating differential pressure transmitters?
  It doesn't calibrate the transmitter itself, but it simulates the transmitter's output so you can calibrate the receiving HMI or PLC scaling.
• How do I wire it for passive mode?
  Usually, you wire the external loop power supply positive to the receiver, the receiver negative to the generator's AOUT+, and the generator's V- back to the loop power ground.