IS200VRTDHID - RTD Processor Board

SPECIFICATIONS

Part No.: IS200VRTDHID
Manufacturer: General Electric
Country of Manufacture: United States of America (USA)
Temperature: 0 to 60 °C
Number of channels: 16
Technology: Surface-mount
Product Type: RTD Processor Board
Availability: In Stock
Series: Mark VI

Functional Description

IS200VRTDHID is an RTD Processor Board developed by GE. It is a part of the Mark VI control system. This board is specifically designed to measure temperature accurately using RTD sensors in industrial applications. It accepts up to 16 three-wire RTD inputs, making it suitable for large-scale temperature monitoring. These RTDs are connected through an RTD terminal board such as TRTD or DRTD via specialized cables with molded connectors to ensure reliable connections.

Features

• Signal Transmission Path: Each RTD sensor is excited by the board to begin the temperature measurement process. The excitation and signal return path run through the connected terminal board to the VRTD board, which is housed within the VME rack. The board transmits a precise excitation current to each RTD, collects the resulting signal, and begins processing the data. This design ensures minimal signal loss and noise interference during transmission, which is essential for accurate temperature readings.
• Excitation Current Functionality: The board provides a 10 mA DC excitation current, which is multiplexed rather than continuously applied. This design helps reduce the heat generated by the RTDs and minimizes self-heating errors. The intermittent excitation ensures the RTDs remain accurate and stable over time while extending their operational lifespan. This excitation current is delivered through the RTD terminal board to each sensor during the scanning cycle.
• Signal Processing and Digital Conversion: Upon receiving the analog signals from the RTDs, the VRTD board uses a Voltage Controlled Oscillator (VCO)-type Analog-to-Digital converter to digitize the data. This converter utilizes voltage-to-frequency conversion and sampling counters to translate resistance values into accurate digital temperature readings. The design ensures high resolution and low latency in data conversion, critical for responsive industrial process control.
• Sampling Rates and Modes: The board offers two distinct sampling modes to meet various operational needs. In normal scanning mode, each signal is sampled four times per second, providing sufficient resolution for most applications. In fast scanning mode, the rate increases to 25 times per second, ideal for systems requiring rapid response to temperature changes. The sampling intervals are synchronized with the power system frequency to eliminate errors due to electrical noise and harmonics.

Communication with VCMI and Controller

Once digitized, temperature values are transmitted via the VME backplane to the VCMI (VME Communication and Monitoring Interface) board. The VCMI then communicates this data to the Mark VI controller, which uses it to regulate and monitor temperature-dependent processes. This seamless integration ensures that real-time temperature data is available for system decision-making, contributing to overall system performance and safety.

Software Linearization and RTD Compatibility

The digital signal processor (DSP) on the VRTD board performs software-based linearization, allowing for accurate interpretation of the RTD signals across a wide range of temperatures. The board supports 15 different types of RTDs, offering compatibility with various sensor materials and standards. This flexibility allows the system to be tailored for specific industrial requirements.

Fault Detection and Channel Management

The board includes advanced diagnostics to detect open and short circuits on any RTD input. If a sensor reading falls outside the hardware-defined limits, that channel is automatically removed from the scan cycle to avoid affecting other measurements. Faulted channels are automatically reinstated after 20 seconds if the problem clears. Alternatively, users can manually restore the channel when maintenance is complete.

The WOC team is always available to help you with your Mark VI requirements. For more information, please contact WOC.

Frequently Asked Questions

What is IS200VRTDHID?
It is an RTD Processor Board developed by GE under the Mark VI series.

How does the VRTD board supply excitation current to RTDs?
The board provides a 10 mA DC multiplexed excitation current to each RTD through the terminal board.

What type of A/D converter does the board use?
The board utilizes a Voltage Controlled Oscillator (VCO) type Analog-to-Digital (A/D) converter.

How often are RTD signals sampled by the RTD board?
In normal mode scanning, signals are sampled four times per second, while in fast mode scanning, the sampling frequency is increased to 25 times per second.

What types of RTD linearization does the VRTD board support?
The board supports linearization for 15 different RTD types, ensuring accurate temperature measurement across various applications.

How does the VRTD board detect faults in inputs?
Faults such as open and short circuits in inputs are detected by monitoring for out-of-range values.

What happens if an RTD is determined to be outside hardware limits?
If found to be outside hardware limits, it is automatically removed from the scanned inputs to prevent adverse effects on other channels.