TRICONEX 3700A analog input module

TRICONEX 3700A analog input module

I. Module Positioning and Application Scenarios

The core component of the safety system: As the analog acquisition module of the TRICONEX trialized safety system (Tricon), it is mainly used to convert the analog signals from on-site sensors into digital quantities for operation and safety logic judgment by the trialized processor.

Typical application fields: Petrochemicals, nuclear power, natural gas processing, metallurgy and other scenarios with extremely high safety requirements, capable of collecting process parameters such as temperature, pressure, flow rate and liquid level.

Ii. Analysis of Functional Characteristics

Multi-channel analog quantity acquisition

Number of channels: 16 isolated analog input channels, supporting the simultaneous collection of 16 different types of analog signals.

Signal type:

Current signal: 4-20mA, 0-20mA, ±20mA;

Voltage signal: 0-5V, 1-5V, ±10V

Thermocouples (TC) : J, K, T, E, R, S, B, N types;

Thermal resistors (RTD) : PT100, PT500, PT1000, etc.

Adjustable input range: Each channel can independently configure the signal type and range to meet the requirements of different sensors.

Triplet signal processing architecture

The module internally performs triplet sampling (A/D conversion) on the analog signals of each channel to generate three sets of independent digital signals, which are transmitted through the backplane to the triplet processor for three-by-two voting to ensure data reliability.

If the sampling value of one channel deviates from the other two channels by more than the threshold, the system automatically identifies and eliminates the faulty data to avoid misoperation.

High-precision and anti-interference design

Conversion accuracy: 16-bit resolution, linearity error ≤0.05%, meeting the high-precision measurement requirements of industrial sites.

Electrical isolation: The isolation degree between channels is ≥500VDC, and the isolation degree between the module and the system backplane is ≥2500VDC, effectively suppressing electromagnetic interference (EMI) and common-mode interference.

Real-time diagnosis and safety mechanism

Self-diagnostic function: Continuously monitor channel open circuit/short circuit, A/D converter failure, power supply abnormality, etc., with a diagnostic cycle of ≤10ms;

Failure handling: If a single channel failure is detected, the module will automatically mark that channel as "invalid", without affecting the operation of other channels. In the event of a module-level failure, the SIL3-level safety failure mode is triggered (such as outputting the preset safety value).

Indicator light feedback: Each channel is equipped with status leds (such as normal signal or FAULT), and the module panel provides PASS/FAULT/ACTIVE indicator lights for on-site maintenance.

Iii. Technical Specifications and Parameters

Number of channels

Equipped with 16 isolated analog input channels, it can independently collect multiple analog signals, avoiding interference between channels and ensuring the accuracy of signal collection.

Signal type

It supports multiple signal types such as current, voltage, thermocouple and thermal resistance, and can be customized to adapt to different industrial sensors such as temperature, pressure and flow, flexibly meeting the needs of various scenarios.

Resolution

It features a 16-bit resolution (±1/65536 LSB), capable of accurately identifying minute signal changes and providing high-precision data support for system control and monitoring.

Accuracy

The full-scale error is ≤±0.05%, and the temperature drift is ≤50ppm/℃. Even under complex working conditions (such as temperature fluctuation environments), it can still stably output high-precision measurement results, ensuring the reliability of system control.

Sampling rate

The single-channel sampling rate is ≥100Hz, which can quickly capture signal transients. The full-channel synchronous sampling is ≥62.5Hz, meeting the requirements of multi-parameter synchronous monitoring and facilitating real-time grasp of the industrial process status.

Isolation characteristic

The isolation between channels reaches 500VDC, and the isolation between the module and the backplane is 2500VDC. This effectively blocks interference signals, enhances the module's anti-interference capability, and is suitable for industrial sites with complex electromagnetic environments.

Working voltage

It is powered by 24VDC, with a voltage fluctuation range of ±15% and a power consumption of ≤15W. It is compatible with industrial standard DC power supply systems, energy-saving and highly compatible.

Temperature range

The operating temperature range is from -40 ℃ to 70℃, and the storage temperature range is from -40 ℃ to 85℃. It can operate stably in harsh environments such as severe cold and high temperatures, and is suitable for outdoor/extreme working conditions in industries like petroleum and chemical engineering.

Security certification

It has passed the SIL3 (IEC 61508) functional safety certification, as well as the ATEX/IECEx explosion-proof certification and UL/cULus industrial safety certification, meeting the compliance and reliability requirements of high-risk and high-safety industries (such as petrochemicals and nuclear power).

Hot plugging support

It supports live plugging and unplugging, and features an anti-misinsertion design and transient protection. During maintenance, there is no need to stop the machine, reducing the risk of system interruption and enhancing the convenience and efficiency of operation and maintenance.

Wiring method

It is connected through an external terminal panel (ETP) and adopts a detachable terminal block, simplifying the cable installation and maintenance process, and facilitating on-site wiring management and fault detection.

Iv. Working Principle and Signal Flow

Signal acquisition and conversion

The analog signals (such as 4-20mA) output by the on-site sensors are connected to the ETP module. After passing through the signal conditioning circuit (filtering and amplification), they are synchronously sampled by the triple A/D converter and converted into digital quantities.

Each group of digital signals is transmitted to the backplane through an independent channel and interfaces with the three channels (A/B/C) of the triplet processor.

Triple voting and communication

The processor conducts a three-by-two vote on the three groups of digital signals. If at least two signals are consistent, this value is adopted as the valid input. If the signals are inconsistent, trigger the diagnostic logic and mark the fault.

The module interacts with the processor in real time through the backplane bus (such as the Tricon dedicated communication protocol), with a transmission rate of ≥10Mbps, ensuring the real-time performance of control instructions.

Fault tolerance mechanism

When A certain channel A/D converter fails, the module automatically switches to the dual-channel working mode and uses the remaining two signals to maintain the system operation. If both channels fail simultaneously, the safety value of that channel (such as 0mA or the preset alarm value) will be output.

V. Installation and Maintenance Characteristics

Hardware compatibility

Compatible with TRICONEX Tricon series chassis (such as 4181, 4351B), it can be directly installed through the backplane slot without the need for additional interface modules.

It supports hybrid networking with other modules of TRICONEX (such as the 3636T relay output module and the 3503E digital input module) to build a complete safety control system.

Maintenance convenience

The hot-swappable design allows modules to be replaced during system operation, and the configuration is automatically restored after replacement (without the need for reprogramming).

Support remote monitoring of the module status through TRICONEX dedicated software (such as Tricon Explorer), export diagnostic logs, and facilitate preventive maintenance.

Vi. Core Differences from Similar Products

Advantages of the triple architecture: Compared with the non-triple analog input module, the 3700A minimizes the impact of single point of failure through hardware redundancy and voting mechanisms, meeting the SIL3-level safety integrity requirements.

Full signal type integration: Supports direct connection of various sensors such as thermocouples and thermal resistors, reducing the configuration of external signal conditioners and lowering system complexity.

Wide temperature range and anti-interference design: Adaptable to harsh industrial environments (such as high temperatures and strong electromagnetic interference), with higher reliability than ordinary commercial-grade modules.