Today, Thai manufacturers are accelerating their transition from traditional production toward automation, robotics, digitalization and Industry 4.0. The Thailand Board of Investment (BOI) continues to encourage manufacturers to upgrade production processes through automation, robotics, digital technologies and smart manufacturing. Its 2026 investment promotion framework also supports automation and robotics adoption in manufacturing and services.

As factories become more automated, the role of industrial control systems is becoming increasingly important. PLCs, DCS, SCADA systems, sensors, transmitters, actuators and other field devices need to exchange signals continuously and reliably.

But there is one often-overlooked challenge:

How can industrial signals be transmitted accurately while protecting control systems from interference, ground loops, voltage differences and potential faults?

This is where signal isolation becomes essential.

Why Do Industrial Automation Systems Need Signal Isolators?

Signal distortion, external interference, interface mismatch and insufficient channel quantity may lead to deviations in monitoring data. In severe cases, they can trigger unintended equipment actions and bring risks of shutdown or safety hazards.

Acrel BM100 & BM200: Reliable Signal Isolation for Industrial Automation

To support the growing demand for reliable industrial automation in Thailand, Acrel BM100 and BM200 series signal isolation products provide a practical solution for signal conditioning and electrical isolation.

I. BM100 Series

The BM100 series analog signal isolators measure electrical parameters such as current and voltage as well as non‑electrical parameters including Pt100 RTDs and potentiometers. After galvanic isolation, they output standard analog signals compatible with pointer meters, digital display meters, PLCs, frequency converters, A/D converters and computer systems. Apart from standard 1‑in‑1‑out, 1‑in‑2‑out and 2‑in‑2‑out versions, extended variants such as 1‑in‑3‑out and 1‑in‑4‑out analog isolators as well as the BM100‑K digital‑switch isolator satisfy diverse engineering requirements for channel counts and signal types.

Product Features

1. Galvanic isolation design Input, output and power supply are mutually isolated with a dielectric strength of ≥1500 V AC/1 min. This mitigates ground‑loop effects and common‑mode interference induced by frequency converters and high‑power motors. It offers protection for downstream PLC cards and suppresses surge impacts.
2. Diverse channel configurations Standard models provide 1‑in‑1‑out, 1‑in‑2‑out and 2‑in‑2‑out options. The 1‑in‑3‑out and 1‑in‑4‑out variants isolate and distribute one analog input into three or four mutually‑independent outputs, where each output channel is also isolated from one another. Both active and loop‑powered passive types are available. Passive models require no auxiliary power and operate purely via the 4‑20 mA signal loop.
3. Broad signal compatibility Accepts DC 4‑20 mA, 0‑20 mA, 0‑5 V, 0‑10 V, Pt100 RTD and potentiometer signals. The 1‑in‑3‑out / 1‑in‑4‑out versions support optional RS485‑Modbus output. Outputs conform to industry‑standard analog levels. Standard‑version transmission accuracy reaches 0.2 %, while multi‑output models achieve 0.1 %. For conventional electrical signals, 90 % of the final value is reached within 5 ms; RTD signals take 1 s; multi‑output units reach 90 % of final value in 0.5 s.
4. Fault‑diagnosis function (1‑in‑3‑out / 1‑in‑4‑out versions) Features over‑current protection for 2‑wire and 3‑wire inputs, open‑circuit detection for 4‑20 mA inputs, and an ALM status LED for fault indication. A 5‑second recovery delay after fault clearance facilitates on‑site loop troubleshooting. Local USB configuration enables custom input‑output mapping.
5. DIN‑rail mounting Two housing thicknesses are offered: 12.5 mm (Type B) and 22.5 mm (Type C), for installation on standard DIN35 rails to save cabinet space. Power supply options include DC 20‑35 V or AC 85‑265 V. Operating temperature ranges from ‑20 ℃ to +60 ℃, suitable for most industrial environments.

（Click picture for details)

II. BM200 Series

For workplaces with flammable‑explosive gas mixtures such as petroleum, chemical and gas industries, apart from anti‑interference performance, it is essential to limit transmitted circuit energy to reduce spark‑ignition risks. The BM200 Galvanically Isolated Safety Barrier integrates signal isolation and conversion plus intrinsic‑safety energy‑limiting functions. It holds 3C explosion‑proof, CE and RoHS certifications and enables signal inter‑communication between hazardous and safe areas.

Two types of galvanically isolated safety barriers are available:

• Field‑side (sensor‑side) isolated safety barrier: Receives signals from field instruments located in hazardous areas, performs isolation and transmits signals to PLC/DCS in safe areas, and restricts reverse energy inflow into intrinsic‑safety loops.
• Control‑side (actuator‑side) isolated safety barrier: Accepts control signals from safe‑area controllers. After isolation and energy‑limiting processing, signals are sent to field equipment within hazardous zones, preventing energy from the control room from entering explosion‑prone areas.

Product Features

1. Compliance with intrinsic‑safety explosion‑proof requirements Built‑in energy‑limiting circuits provide 2500 V AC isolation between intrinsic‑safety and non‑intrinsic‑safety sides. With CCC explosion‑proof certificate, CE and RoHS reports, the unit limits voltage and current fed into hazardous areas. In case of loop short‑circuit faults, it minimizes energy capable of igniting explosive mixtures and meets intrinsic‑safety standards for petrochemical applications.
2. Comprehensive signal‑processing capability Compatible with 2‑wire and 3‑wire transmitters. Supports RTD, voltage and low‑current inputs. Delivers standard analog outputs such as 4‑20 mA and 0‑5 V and supports multi‑channel signal distribution.
3. Unified mechanical installation Adopts the same DIN‑rail mounting scheme as the BM100 series, simplifying cabinet‑system design for complete‑set projects and lowering engineering workload.

（Click picture for details)

Why Choose Acrel BM100 & BM200?
1.Reliable Signal Isolation

Electrical isolation helps reduce the impact of ground loops, electrical interference and potential differences between field devices and control systems.

2.Multiple Signal Types

The BM series can handle a range of industrial measurement signals, including voltage, current, temperature and resistance signals, making it easier for system integrators to build flexible automation systems.

3.Protection for Automation Systems

By providing an isolation interface between field equipment and control equipment, the BM series can add an extra layer of protection for PLC, DCS and other automation devices.

4.Compact Industrial Solution

Signal isolators are commonly installed inside control cabinets and automation panels. A compact isolation solution helps system integrators optimize cabinet space and simplify wiring.

（Application of BM series signal Isolators in a factory）