Slide Valve Operation

Slide Valve Actuator Operation

The slide valve actuator is a gear-motor with a posi- tion sensor. The motor is powered in the forward and reverse directions from the main computer in the control panel. The position sensor tells the main computer the position of the slide valve. The main computer uses the position and process information to decide where to move the slide valve next.

The position sensors works by optically counting mo- tor turns. On the shaft of the motor is a small alumi- num “photochopper”. It has a 180 degree fence that passes through the slots of two slotted optocouplers. The optocouplers have an infrared light emitting di- ode (LED) on one side of the slot and a phototransistor on the other. The phototransistor behaves as a light controlled switch. When the photochopper fence is blocking the slot, light from the LED is prevented from reaching the phototransistor and the switch is open. When photochopper fence is not blocking the slot, the switch is closed.

As the motor turns, the photochopper fence al- ternately blocks and opens the optocoupler slots, generating a sequence that the position sensor mi- crocontroller can use to determine motor position by counting. Because the motor is connected to the slide valve by gears, knowing the motor position means knowing the slide valve position.

During calibration, the position sensor records the high and low count of motor turns. The operator tells the position sensor when the actuator is at the high or low position with the push button. Refer to the calibration instructions for the detailed calibration procedure.

The position sensor can get “lost” if the motor is moved while the position sensor is not powered. To prevent this, the motor can only be moved electrically while the position sensor is powered. When the posi- tion sensor loses power, power is cut to the motor. A capacitor stores enough energy to keep the position sensor circuitry alive long enough for the motor to come to a complete stop and then save the motor position to non-volatile EEPROM memory. When power is restored, the saved motor position is read from EEPROM memory and the actuators resumes normal function

This scheme is not foolproof. If the motor is moved manually while the power is off or the motor brake has failed, allowing the motor to free wheel for too long after the position sensor looses power, the ac- tuator will become lost.

A brake failure can sometimes be detected by the position sensor. If the motor never stops turning after a power loss, the position sensor detects this, knows it will be lost, and goes immediately into calibrate mode when power is restored.

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Emerson VSS, VSR, VSM service manual Slide Valve Operation, Slide Valve Actuator Operation
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VSS, VSM, VSR specifications

Emerson VSM, VSR, and VSS are advanced technologies designed for process automation and control, often utilized in industrial applications. These systems are part of Emerson's broader portfolio of solutions aimed at enhancing operational efficiency, safety, and reliability.

The Emerson VSM, or Valve Signature Management, focuses on the digital management of valves within a system. One of its main features includes advanced diagnostics that monitor the health and performance of control valves. This technology allows for predictive maintenance, ensuring that valves operate at peak efficiency and reducing the risk of unexpected failures. The VSM utilizes a combination of smart sensors and actuators to gather data, enabling real-time analytics that can enhance decision-making and operational strategies.

On the other hand, VSR, or Valve Status Reporting, enhances visibility into the operational state of valves in real time. This system provides operators with critical updates and alerts related to valve conditions, significantly reducing response times to potential issues. The VSR technology integrates seamlessly with existing control systems, allowing for easier implementation and minimal disruption to ongoing operations. The reporting capabilities feature user-friendly dashboards that present complex data in a straightforward manner, empowering operators to make informed decisions quickly.

The Emerson VSS, or Valve Service Solutions, complements the VSM and VSR by focusing on the maintenance and support of valve systems. This offering includes comprehensive service packages that range from routine maintenance to advanced troubleshooting and repair. The VSS is designed to improve the lifespan of valves through proactive service, ensuring reliability and minimal downtime. Emerson’s trained technicians leverage predictive analytics derived from VSM and VSR data, allowing for timely intervention before issues escalate.

In summary, Emerson’s VSM, VSR, and VSS technologies work together to create a robust ecosystem for valve management in industrial settings. The combination of advanced diagnostics, real-time reporting, and comprehensive service solutions provides operators with a powerful toolkit aimed at optimizing performance and ensuring operational reliability. With these technologies, companies can embrace digital transformation, reduce operational risks, and improve overall process efficiency, leading to a safer and more productive environment. Each component plays a crucial role in empowering industries to meet the challenges of modern automation and maintain competitive advantages in their respective markets.
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