Best 4-20 Signal Generators for PLC Testing and Lab Use
The top pick 4-20 mA signal generators for PLC testing, voltage/current simulator, and real-time signal analysis. These devices are best for electronics technicians, control engineers, and labs needing precise current or voltage signals, with some models offering PWM outputs and multi‑signal types. The following selections balance precision, versatility, and ease of use for indoor bench work or field maintenance.
Summary of selected products:
| Product | Key Benefit | Best For |
|---|---|---|
| Riiai SG003A 4-20mA/0-24V | Multiple signal types, real-time curve, long battery life | Bench testing and PLC calibration |
| DROK 4-20mA Generator | Dual signal output (0-20 mA and 0-10 V) in one unit | Compact, simple signal generation |
| Riiai 0-10V 0/4-20mA | 2-in-1 voltage/current with 4-digit display | Dual-display quick readouts |
| LB78 Current Voltage Signal Generator | Calibrator quality with independent keys | Maintenance and field calibration |
| TestHelper TH-71B | Multimodal with thermocouple support | General measurement and source output |
Riiai SG003A 4-20mA/0-24V Signal Generator
This multi‑mode generator supports mA current, V voltage, XMT passive current, and Hz pulse signals. It converts inputs into several output types, enabling flexible PLC testing and signal simulation. The 2.4 inch TFT color screen with backlight aids operation in various lighting. A built-in 3000 mAh battery provides extended field use, with full recharge in a few hours and long runtime. Best for technicians who need versatile signal types in one device and occasional portable use.
Best for: technicians and PLC testers who require multiple signal types in a single handheld unit. Better for: on‑site field calibration thanks to battery power. Caution: battery life depends on backlight use and signal type; plan charging accordingly.
DROK 4-20mA Generator
This compact module provides 0/4–20 mA current along with 0–10 V voltage output via a single device, controlled by a precise potentiometer. It is a straightforward option for quick signal generation in lab benches or field service. The dual-output design makes it useful when you need both current and voltage signals without carrying multiple tools. Best for: users who want an affordable, simple dual-signal generator. Caution: single module limits simultaneous display to one value at a time; check measurement needs before purchasing.
Riiai 0-10V 0/4-20mA Current Voltage Generator
This 2‑in‑1 device delivers -10 V to +10 V and 0–22 mA with 0.01 unit precision for both voltage and current. An encoder knob with 20 pulses per turn allows precise adjustments, and a 4-digit display provides quick readouts. It supports multiple power modes, including internal battery and external DC input. Best for: users who want clear readouts and precise calibration in a compact unit. Choose this if you value a built‑in display for quick comparison of voltage and current. Limitation: display and battery convenience may be reduced under heavy field use.
LB78 Current Voltage Signal Generator
The LB78 focuses on reliability and ease of operation with a dedicated control layout and independent keys for each function. It includes safety features like a built-in fuse to protect against misconnection. This makes it well-suited for PLC maintenance and field calibration where robust hardware and predictable behavior matter. Best for: technicians who need stable performance with simple, fast access to each function. Caution: its feature set is robust but not as feature-dense as multi-signal models.
TestHelper TH-71B Handheld Signal Generator
TestHelper TH‑71B combines voltage, current, and thermocouple measurement with source output, including a 24 V loop supply. It emphasizes portable measurement alongside signal generation, making it a versatile pick for technicians who need integrated measurement in the field. Best for: on‑site technicians who require a handheld tool with multiple measurement modes. Caution: basic accuracy is stated as 0.2%, which may be lower than precision-grade lab devices.
Buying Guide
- What signals do you need? If you require multiple types (current, voltage, and pulse), choose a model like SG003A or TH‑71B. If you mainly need a simple DC current/voltage source, a DROK model may suffice.
- How important is a display? Devices with 4‑digit displays or color LCDs help with quick reading and calibration; consider the Riiai 0-10V 0/4-20mA or LB78 for easy visibility.
- Portability vs. bench stability: Battery-powered handheld units excel in the field, while tabletop units offer larger displays and more stable measurements.
- Power options: Look for built-in rechargeable batteries for field use or external power compatibility (micro USB, DC input) for lab work.
- Accuracy and resolution: If high precision matters, prioritize products listing 0.01 mA/0.01 V resolutions and clear calibration controls.
- Safety features: Fuses or protection against misconnection help prevent instrument damage during maintenance tasks.
Frequently Asked Questions
- What is a 4-20 mA signal generator used for? It creates standardized current or voltage signals to test PLCs, controllers, and instrumentation in automation systems.
- Can these devices simulate PWM signals? Some models offer PWM outputs or square-wave outputs in addition to current and voltage signals.
- Is battery life important for field work? Yes. A longer runtime reduces recharge interruptions during on-site calibration or testing.
- Do these units support both 0-10 V and 0-20 mA ranges? Several models provide both ranges; check each product’s specifications for exact limits.
- What should I consider when choosing? Prioritize signal types needed, display/readout convenience, portability, and calibration features.