ABB Bailey SPASO11 Analog Output (AO) Module

ABB Bailey SPASO11 is an analog output safety barrier module designed specifically for explosion-proof environments in the Bailey series. It is mainly used in industrial fields with flammable and explosive risks such as chemical industry, petroleum, and natural gas. It acts as a "safe signal converter" in the system, which can not only receive analog control signals from controllers in the safe area but also safely transmit signals to actuators in the hazardous area (such as explosion-proof valve positioners and explosion-proof control valves) through intrinsic safety design. At the same time, it strictly limits the energy output to the hazardous area to prevent explosion accidents caused by excessive energy, ensuring the accurate execution of control commands in hazardous environments.

• Power Adaptation: The working power supply on the safe side is 24V DC, with an allowable voltage fluctuation range of 19.2V - 28.8V DC, adapting to standard DC power supplies in industrial sites; the hazardous side does not require independent power supply, and control signals and weak energy are transmitted through signal lines, meeting intrinsic safety requirements; the power consumption on the safe side is about 2.8W, and the low-energy design reduces heat generation, ensuring long-term stable operation of the module.
• Signal Output: Equipped with 2 independent analog output channels, which can output 4 - 20mA DC current signals, a standard control signal commonly used by actuators in hazardous areas. The isolation voltage between the safe side and the hazardous side reaches 2500V AC, and the isolation voltage between channels is 1000V AC, effectively blocking dangerous energy conduction and signal interference.
• Output Accuracy and Load Capacity: The output accuracy reaches ±0.1% FS, which can accurately reproduce the control commands of the controller. For example, when converting a 0 - 100% valve opening command into a 4 - 20mA signal, the error can be controlled within ±0.1%; each channel has a maximum load resistance of 500Ω, which can drive actuators at longer distances in hazardous areas, ensuring stable signal transmission without attenuation.
• Environmental Adaptability: The operating temperature of the safe side is -20℃ - +60℃, and that of the hazardous side is -40℃ - +70℃, enabling reliable operation in extreme temperature difference environments; the relative humidity is 5% - 95% (non-condensing), adapting to humid coastal industrial areas or rainy season environments; the anti-vibration performance complies with IEC 60068-2-6 standards, capable of withstanding vibration shocks of 10Hz - 150Hz, adapting to the vibration environment near pump sets and compressors.
• Physical Specifications: It has a size of approximately 105mm×85mm×65mm and a weight of about 0.3kg. It adopts DIN rail mounting, and its compact structure saves space in the control cabinet, suitable for explosion-proof control systems with high-density installation.

• 
  

• Intrinsic Safety Output Control: Adopting an energy and current limiting circuit design, it strictly controls the energy output to the hazardous area (voltage ≤ 30V, current ≤ 30mA). Even in case of module failure, the output energy will not exceed the ignition threshold of explosive mixtures. For example, when a short circuit occurs in the output circuit, the internal current-limiting protection circuit will quickly limit the current to a safe range, eliminating the risk of explosion from the source.
• Bidirectional Isolation Mechanism: It realizes bidirectional isolation of signals and power supplies. Signal isolation cuts off electrical connections through optocouplers, and power isolation uses isolated DC/DC converters to prevent energy exchange between the safe area and the hazardous area. The double isolation greatly reduces the risk of hazard transmission and improves system safety.
• Real-Time Fault Diagnosis: It has a complete self-diagnostic function, which can monitor output short circuits, disconnections, over-ranges, as well as module power supply abnormalities and isolation faults. When a fault is detected, the LED indicator on the safe side (such as a yellow alarm light staying on) prompts in time, and sends a fault code to the upper system through the bus (such as "E02: Channel 1 short circuit"), facilitating maintenance personnel to quickly troubleshoot, and the diagnosis process does not affect normal signal output.
• Anti-Interference Optimization: It integrates multi-level filter circuits (low-pass filter, electromagnetic interference filter) inside, which can effectively suppress electromagnetic noise and high-frequency interference in industrial sites. In factory areas with dense high-voltage motors and frequency converters, it can ensure the stability of output signals, avoid misoperation of actuators caused by interference, such as preventing regulating valves from unnecessary opening changes due to signal fluctuations.
• System Compatibility: It can be seamlessly integrated into ABB Bailey Symphony Plus, INFI 90 and other DCS systems, supporting online configuration and parameter setting (such as output range calibration, filter time adjustment), and communicating with the controller at high speed through the system bus. It is also compatible with third-party safety instrumented systems (SIS) and follows standard protocols such as Modbus, simplifying cross-brand system integration.

• 
  

• Petroleum Refining Units: In the atmospheric and vacuum distillation unit of a refinery, SPASO11 is installed in the control cabinet of the safe area, receives the temperature control signal from DCS, converts it into a 4 - 20mA signal and transmits it to the explosion-proof control valve in the hazardous area. Through the intrinsic safety design, it limits the energy output to the control valve, and at the same time accurately controls the valve opening, adjusts the fuel supply of the heating furnace, ensures that the crude oil distillation temperature is stable within the process range, and avoids dangers caused by overheating.
• Chemical Reactor Control: In the control system of polymer reactors in chemical plants, this module converts the pressure control command of the PLC in the safe area into an analog signal and transmits it to the explosion-proof valve positioner in the hazardous area to control the opening of the feed valve. The module strictly limits the output energy to prevent sparks near the reactor containing flammable and explosive monomers, and at the same time ensures that the valve opening control accuracy reaches ±0.5% to keep the reaction pressure stable.
• Natural Gas Pipeline Transportation: In the booster station of long-distance natural gas pipelines, SPASO11 receives the pressure regulation signal from the SCADA system, outputs a 4 - 20mA signal to the explosion-proof pressure control valve in the hazardous area, and controls the natural gas pressure in the pipeline. Through the energy-limiting design of the safety barrier, it prevents the electric energy of the station control system from entering the explosion-proof area, and at the same time ensures that the control valve acts quickly (signal transmission delay <10ms), ensuring that the pipeline pressure fluctuates within a safe range.
• Pharmaceutical Explosion-Proof Workshops: In the fermentation workshop for antibiotic production, this module converts the stirring speed command of the controller in the safe area into an analog signal and transmits it to the explosion-proof frequency converter in the hazardous area to control the rotation speed of the stirring motor. The intrinsic safety characteristics of the module match the explosion-proof level of the workshop, avoiding potential safety hazards in the alcohol vapor environment, and at the same time ensuring the speed control accuracy of ±1% to keep the fermentation process uniform and stable.