Foxboro FBMSVH I/A Series Precision Closed-Loop Servo Control Module

Description

• Output Parameters
  • It outputs ±27 mA current to drive servo valves, and the maximum output current of the power amplifier can reach ±30 mA when matched with an 80 Ω load.
  • It provides a 0 – 20 mA valve position signal output with an output impedance of 50 Ω, and the external current feedback load impedance is 500 Ω with a maximum feedback current of 21 mA.
  • The external shutdown contact outputs -10 mA current when closed to achieve emergency shutdown control.
• Environmental Specifications
  • The operating temperature range is 0 °C to 50 °C, and the storage temperature range is -40 °C to 70 °C.
  • The module weighs 2000 grams and can operate stably in industrial environments with non-condensing humidity, adapting to the general electromagnetic and temperature fluctuation conditions of industrial sites.

Function Features

• Dual Input Modes and Flexible Regulation

  The module supports both 4 – 20 mA current and 0 – 10 VDC voltage input commands, which can be flexibly matched with different upper-level control system signal outputs. It offers selectable proportional or proportional-integral control modes, where the proportional gain can be adjusted from 0 to 20 and the integral time constant from 1 to 20 seconds. Operators can customize control behaviors through parameter adjustments such as gain and integral time to adapt to the response characteristics of different pneumatic or hydraulic servo systems.

• Precise Closed-Loop Control with Feedback Mechanism

  It integrates an LVDT modulator and demodulator to process LVDT feedback signals efficiently. By comparing the input control commands with the real-time LVDT feedback signals and conducting proportional or proportional-integral calculations, the module continuously adjusts the output current to drive servo valves. This closed-loop control mechanism ensures sub-millimeter accuracy in valve positioning, which is critical for industrial processes requiring high-precision motion control.

• Comprehensive Monitoring and Safety Protection

  It provides a 0 – 20 mA valve position signal output that enables the upper-level DCS to real-time monitor the operating status of the servo valve. The external shutdown contact design allows for emergency shutdown operations; when the contact is closed, the module outputs -10 mA current to trigger the shutdown process. This feature prevents equipment damage or production accidents caused by abnormal servo system operations, enhancing the safety and reliability of the entire control system.

• Strong Compatibility and Easy Integration

  As a component of the Foxboro I/A Series, the module can be seamlessly integrated into the I/A Series distributed control architecture without compatibility issues. It maintains stable communication and signal interaction with other modules and controllers in the system. Its standardized signal input and output formats also facilitate connection with various types of servo valves, LVDT sensors and other field equipment, reducing the difficulty of system integration and configuration.

Application Scenarios

• Power Generation Industry

  It is widely used in steam turbine control systems of thermal power and nuclear power plants. It processes the DEH command signals of steam turbines and cooperates with LVDT sensors to precisely control the opening of steam valves. The precise valve positioning ensures stable steam intake and load regulation of the turbine, which is essential for maintaining the stable operation of the generator set and improving power generation efficiency. In case of abnormal conditions, the external shutdown function can quickly cut off the servo drive signal to protect the turbine from damage.

• Oil and Gas Industry

  It is deployed in oil drilling platforms, oil refineries and natural gas processing plants. It is used to control the hydraulic servo actuators of wellhead control valves, pipeline regulating valves and other key equipment. It adjusts the valve position according to the pressure, flow and other process parameters transmitted by the control system to ensure stable transportation and processing of oil and gas. Its strong anti-interference ability adapts to the harsh electromagnetic environment of drilling platforms and ensures continuous and reliable operation of the control system.

• Chemical Industry

  It is integrated into chemical production processes such as reaction kettles and distillation columns. It controls the pneumatic or hydraulic servo valves that regulate the flow of raw materials and the discharge of products. For example, in the polymer synthesis process, the module precisely adjusts the opening of the raw material feeding valve to maintain the reaction temperature and pressure within the set range. The flexible parameter adjustment function enables it to adapt to the replacement of different raw materials and changes in process conditions, ensuring the stability and consistency of product quality.

• Pulp and Paper Industry

  It is applied in key equipment of pulp and paper production lines, such as paper machines and pulp beaters. It controls the servo systems of the paper machine’s traction roller and thickness adjustment valve, realizing precise control of paper thickness and tension. Stable servo control ensures that the paper surface is flat and the thickness is uniform, reducing the rate of unqualified products. At the same time, the module’s reliable operation ensures the continuous operation of the high-speed paper machine and improves production efficiency.

• Automotive Manufacturing Industry

  It is used in hydraulic servo control systems of automotive stamping and welding equipment. It controls the movement of stamping dies and welding fixtures through driving servo valves, ensuring the accuracy of stamping dimensions and welding positions. The high response speed and control precision of the module enable the equipment to complete complex stamping and welding operations efficiently, improving the assembly accuracy and production quality of auto parts.