DS3820T1MC - 8-Channel Optocoupler Voltage Isolation Module

SPECIFICATIONS:

Part No: DS3820T1MC
Manufacturer: General Electric
Series: Mark IV
Product Type: 8-Channel Optocoupler Voltage Isolation Module
Number of Channels: 8
Input Voltage Range: 3.3V to 24V
Power Requirements: 24V DC,
Isolation Voltage:2,500V to 5,000V
Insulation Resistance: ≥ 100M Ohms
Input Current: 5mA to 20mA
Output Range: 0-10 V, 4-20 mA
Communication Ports: RS232, RS485
Dimensions: 150 mm x 100 mm x 30 mm
Mounting: Standard mounting
Operating Temperature: -40°C to +85°C
Country of Origin: USA
Availability: In Stock

FUNCTIONAL DESCRIPTION:

DS3820T1MC is an 8-channel Optocoupler Voltage Isolation Module manufactured and designed by General Electric and is part of the Mark IV Series used in GE Speedtronic gas turbine control systems. The 8-channel optocoupler module provides reliable electrical isolation between high-voltage inputs and sensitive low-voltage control circuits. By using optocouplers (opto-isolators) for each channel, the module allows signals to pass through without direct electrical contact, ensuring galvanic isolation. This protects microcontrollers, PLCs, and other logic-level devices from voltage spikes, electrical noise, transient surges, and ground loops that are common in industrial and embedded systems. Each channel converts input voltage changes into optical signals, which are then received by phototransistors on the output side, allowing safe and accurate signal transmission.

The module typically supports input voltages from 5V to 24V DC and provides fast response times suitable for real-time control applications. It is widely used in industrial automation, robotics, motor control, instrumentation, and IoT systems, enabling multiple signal isolations in a compact, reliable, and efficient form factor. By preventing hardware damage and minimizing signal interference, the 8-channel optocoupler module enhances system stability and extends the life of connected devices.

OPERATIONS:

The 8-channel optocoupler module operates by electrically isolating input signals from output signals using optocouplers. When a voltage signal is applied to the input side of a channel, it powers an LED inside the optocoupler. The light emitted by this LED is detected by a phototransistor on the output side, which switches accordingly to replicate the input signal on the low-voltage side. This process ensures that the high-voltage input does not electrically contact the output, preventing damage to sensitive devices like microcontrollers, PLCs, or other logic-level circuits. The module supports digital signals and is compatible with TTL or CMOS logic levels. The fast response time of the optocouplers allows real-time signal processing, while the high isolation voltage protects against surges, spikes, and electrical noise in industrial or embedded systems.

CONFIGURATION:

The 8-channel optocoupler module is typically configured with screw terminals or pin headers for both input and output connections, allowing easy interfacing with controllers, sensors, and external circuits. The configuration allows the module to simultaneously isolate multiple signals while maintaining fast response times, stable operation, and protection against voltage spikes or noise in industrial and embedded systems. Each of the eight channels has a dedicated input and output, which function independently, providing flexibility in multi-signal applications.

• Input Side: Designed to accept digital signals, usually in the range of 5V to 24V DC, depending on the module specifications. Pull-up resistors may be integrated to ensure stable input detection.

• Output Side: TTL or CMOS logic compatible, allowing direct connection to microcontrollers, PLCs, or other low-voltage devices. Open-collector or transistor outputs are commonly used for flexible interfacing.

• Isolation: Each channel is electrically isolated, typically rated for 2.5kV to 5kV AC, ensuring safe signal transfer and protection of sensitive devices.

• Power Requirements: Low current consumption per channel, usually around 5–20 mA, supplied via the input voltage line.

• Mounting: The module can be mounted on standard PCB surfaces, DIN rails, or integrated into custom enclosures, depending on the application.

WOC offers the largest inventory of replacement parts for GE Speedtronic Gas Turbine Control Systems, including unused, rebuilt, and fully refurbished modules, all backed by a reliable warranty. In addition to providing high-quality components, we offer expert repair services for faulty boards, using advanced diagnostics and repair techniques to extend equipment life and ensure optimal system performance. Our team of experienced engineers is available 24/7 to provide technical guidance, compatibility support, pricing, and availability information, helping minimize downtime and maximize operational efficiency. Whether sourcing replacement modules, repairing existing components, or seeking expert advice, WOC delivers fast, dependable, and cost-effective solutions to keep your turbine control systems running safely and reliably.

FREQUENTLY ASKED QUESTIONS:

What is the typical Current Transfer Ratio (CTR) of each optocoupler channel?

Each channel typically has a CTR in the range of 50% - 600%, depending on the module design and input current. This ratio indicates the efficiency of signal transfer from the LED to the phototransistor and affects output voltage levels under varying loads. CTR decreases slightly at higher temperatures or lower input currents.

What are the collector-emitter voltage (VCE) and collector current C limits?

The phototransistor output typically supports a collector-emitter voltage up to 30V–50V DC and a collector current of 50–100 mA per channel. Exceeding these limits can damage the transistor or reduce isolation reliability.

What is the maximum switching frequency the module can reliably handle?

The module can operate at switching frequencies up to 50 kHz for typical digital signals, depending on load resistance and input current. Rise and fall times are usually between 5–15 µs, and careful consideration of pull-up resistor values is required for high-speed applications.

How is the isolation voltage tested and rated?

Each channel is typically rated for 2.5 kV–5 kV AC isolation for 1 minute, tested using dielectric strength testing according to IEC 60747 standards. This ensures safe operation under transient overvoltage conditions between high- and low-voltage circuits.