New Flow Meter Simplifies Gas Mixing and Blending Systems

With its advanced capabilities, the Smart-Trak® 2, coupled with Sierra’s new Compod™, simplifies production of basic flow control applications, such as gas mixing and blending systems, by permitting easy setup and networking of multiple instruments using open-source MODBUS RTU protocol. A Smart-Trak® 2 with Compod™ can replace much more expensive DCS or PLC systems, allowing end users to automate a wide variety of processes. Two digital outputs and one analog input can be configured by the end user, while the Compod monitors the functionality of the mass flow meter or controller and provides diagnostics, notifying users of faults or system upsets.

Gas Mixing and Blending Made Easy

A specific gas blend must be produced. In this example, synthetic air composition is maintained at 78% N2, 21% O2 and 1% Ar. A miniature Human/Machine Interface (HMI) with LCD touch screen monitors and controls the system automatically. The HMI communicates to three mass flow controllers (via their attached Compods) and a pressure transducer mounted inside the tank. Each MFC regulates the flow of one gas in to the tank. The HMI maintains the exact proportion defined above by constantly monitoring these MFCs. When the pressure reaches the set point, the PLC commands the Compods stop the flow controllers.

Should the pressure drop below the set point, the PLC sends a flow command to each controller to resume gas flow into the tank. The system is fully automatic. Each Compod™ includes a safety program that monitors the gas flow through its attached controller. Should the flow through a controller drop off when the setpoint from the HMI remains on, the Compod™ detects that the gas supply has been interrupted (such as when a bottle runs out) and triggers an alarm that shuts down the system. If the ratio of the gases in the synthetic air mixture needs to be modified, simply change the recipe in the PLC and the system provides the new mixture, immediately and automatically.

Other Flow Applications Made Easy
 

• Batch control
• Leak Testing
• Process monitoring
• Physical Vapor Deposition (Sputtering)
  View all applications made easy using Smart-Trak® with Compod.
  
  
  Smart-Trak® Features:
  • Accuracy of +/- 1% of full scale
  • Accuracy of +/- 0.7% of reading +.3% of FS
  • 316 stainless steel construction
  • Flow ranges from 0 to 10 sccm to 0-1000 slpm.
  • Fast-response control valve
  • True digital performance with great flexibility
  • “Primary Standard” calibration& NIST traceability
  • Dial-A-Gas® Technology
  • 10 pre-programmed gases come standard
  • Substitute up to 9 gases of your own
  • Unique pilot module allows field adjustment of key control functions
  • Source code for RS-232 communication provided
  • Multi-drop RS-485/MODBUS RTU (Using Compod)
  • Small footprint makes drop-in replacement easy
  • Single-sided 24 Vdc power supply
  • CE approval
  
  Additional Compod™ Features:
  • Controls simple processes without the need for external PLCs or computers
  • Acts as a vital link in a complex process control network
  • Monitors the operation of instruments and provides potential problem alerts
  • Is available with a local LCD Display for local monitoring
  • Can be used with new instruments or added to existing models