Best 4 to 20 mA Generator for PLC Testing
The top pickers for a 4-20 mA signal generator are devices that offer precise current output, reliable voltage output, and user-friendly interfaces for PLC testing. This guide covers five suitable models, explaining who each is best for and why. It helps engineers, technicians, and maintenance personnel decide which tool fits their workflow, power availability, and display needs. A concise comparison table is included below to aid quick assessment.
| Product | Best For | Key Feature |
|---|---|---|
| Riiai 0-10V 0/4-20mA Current Voltage Signal Generator | PLCs and panel debugging with dual voltage/current output | 4-digit display; rechargeable battery; multiple power modes |
| Riiai SG003A 4-20mA 0-24V Current Signal Generator | Long sessions, real-time curves, multiple signal types | 4-20 mA, 0-24 V, USB rechargeable, TFT color screen |
| Adjustable Signal Generator 4-20mA 0-12V | Calibrated output with short-circuit protection | 0-12 V output, 4-20 mA default, extended battery life |
| Riiai 0-10V 0/4-20mA PWM Output Generator | Combined PWM, voltage, and current testing | Integrated PWM output, portable, precise adjustments |
| TH-71B Handheld Signal Generator | On-site tests with thermocouple and loop supply | Thermocouple support, 24V loop, versatile testing |
Riiai 0-10V 0/4-20mA Current Voltage Signal Generator
Best for engineers needing both voltage and current outputs with a compact, rechargeable unit. It offers -10V to +10V voltage range with 0.01V precision and 0-22 mA current with 0.01 mA precision. The 4-digit display makes mode switching between voltage and current straightforward. Battery-powered operation via a built-in 1000 mAh cell plus options to power from micro USB or external 15–30 V DC increases field usability. Suitable for PLC debugging and device testing where portable operation matters. A potential limitation is the single-knob adjustment, which may require more turns for fine-tuning in some scenarios.
Riiai SG003A 4-20mA 0-24V Current Signal Generator
Best for users who need versatile signal type support beyond simple current output. It switches among mA (0–24 mA, 0.01 mA precision), V (0–24 V, 0.01 V), XMT passive current, and Hz pulse signals (0–9999 Hz, five-digit precision). The large 4.3-inch-ish TFT color display aids visibility in various lighting conditions. A 3000 mAh USB rechargeable battery supports long operation times. Choose this if you require multiple signal types from a single device, but beware the higher feature density may require a learning curve for beginners.
Adjustable Signal Generator 4-20mA 0-12v
Best for applications needing reliable 4-20 mA current with a controlled 0–12 V range and short-circuit protection. It offers a 1500 mAh battery, 0–24 mA current with calibration accuracy around 0.05 mA, and short-circuit protection to guard test setups. The unit provides easy battery-powered operation for fieldwork, but charging can take several hours. It’s a solid choice when stability and basic safety features are priorities and space is limited.
Riiai 0-10V 0/4-20mA PWM Output Generator
Best for testers who need integrated PWM functionality along with voltage and current outputs. It supports 0–24 mA current with 0.05 mA precision and ±12 V voltage with 0.03 V precision. The device runs on a built-in 1500 mAh battery for cordless operation, suitable for on-site maintenance where power access is limited. A caveat is that longer sessions may demand periodic recharging when using PWM at higher duty cycles.
TH-71B Handheld Signal Generator
Best for on-site signal generation with versatility across voltage, current, and thermocouple measurements plus 24 V loop supply. It provides a compact form factor suitable for field engineers. This model’s thrust is its broad compatibility with basic lab and field measurements. A limitation may be the basic accuracy specification and absence of advanced digital interfaces compared to higher-end models.
Buying Guide
- Output range and precision: Look for devices offering 0.01 V / 0.01 mA precision for critical calibration tasks and a voltage range that covers your test needs.
- Signal types: If you require more than current output, choose models that support voltage, PWM, and even Hz or thermocouple capabilities to consolidate tools.
- Display and usability: A bright LCD/TFT screen and mode-switching ease help during day and night testing. Confirm whether displays show real-time values clearly.
- Power options: Battery-powered units offer portability; however, confirm charge time and operating hours to match field work duration.
- Protection features: Short-circuit protection and overcurrent safeguards protect both the device and the test setup.
- On-site practicality: For field use, preference should be given to compact, lightweight designs with rechargeable batteries and robust enclosures.
- Maintenance and calibration: Verify calibration capabilities and how easy it is to recalibrate for long-term accuracy.
Frequently Asked Questions
- What is a 4-20 mA signal generator used for?
It provides a controlled current loop signal (4-20 mA) used to simulate sensors and transmitters for PLCs and industrial control systems.
- Do these devices support both voltage and current outputs?
Many models offer both voltage and current outputs, with some also including PWM or frequency-based signals for broader testing needs.
- Is a rechargeable battery necessary for field testing?
Battery power is highly beneficial for on-site work where access to outlets is limited, though external power options may be available on some models.
- What should I consider when choosing between models with a TFT display vs. a basic display?
A TFT color display often provides clearer visuals and easier navigation, especially in low-light conditions, while basic displays save cost and power.
- How important is short-circuit protection?
Short-circuit protection can prevent damage to the device and the test setup, making it a key safety feature for bench and field use.