FCI ST100A Series, Installation, Operation And Maintenance Manual

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OPERATION ST100A Series Flow Meter
46 Fluid Components International LLC
Configuring for AST™ or Constant Power Measurement Methods
The default factory sensor heater configuration is AST™ (Adaptive Sensing Technology) in which the instrument automatically transitions
between constant Delta T operation (heater power to maintain Delta T proportional to flow) and constant power operation (constant heater
power and sensor Delta T proportional to flow) to measure the flow rate. Refer to Theory of Operation , page 1 . The alternate heater mode
choice is Constant Power mode (only).
Caution: Only in certain cases should the instrument be configured from AST™ to Constant Power. Consult the factory for
guidance to determine if the Constant Power mode is optimum for your process conditions.
Use the configuration software to set the heater mode to AST or Constant Power as follows (refer to the ST100A Configuration Software
manual 06EN003481 for software details):
1. Access the AST Power Mode tab from the Configuration branch of the menu tree. See Figure 45 below.
2. In the AST Heater Power Mode field, pull down the Power Setting menu and select Constant Power or AST (default).
3. If AST is selected, pull down the Max. Current menu and select the maximum current at which the unit transitions to Constant
Power: 105 mA or 90 mA (default).
Note: The VC and VD data fields are DAC values used in the heater modes. This data is for factory use only.
Figure 45 – Example AST Power Mode Tab (Configuration)