Two options are specific to calibrating Smart Valve hardware.
- Calibrate Torque
Torque is a measure of how much stress is on the valve stem, and is only useful for a TOTS valve as an indication of how hard the disc is forced against the seat. The controller will turn off the motor when the torque reaches the configured torque limit. Torque will read close to zero when the motor is not energized and the valve is not closed. Torque will read a small positive or negative percentage while the motor is opening or closing the valve before it gets into the seat zone. Only when the plate starts to connect to the seat do the torque readings quickly ramp up towards +/- 100%.
- Calibrate Pressure
There is a pressure transducer on each side of the valve which directly measures fluid pressure and produces a voltage. No part of the pressure calibration is concerned with flow rates. Flow rate is calculated in the operator based on pressure differentials. The pressure calibration deals with percent of maximum gauge and differential pressures.
When Calibrate Torque is selected, the dialog below is displayed.
Calibration cannot take place unless a connection is present between the Design Pad PC and the valve. This can be accomplished with an I/R wand or, in this case, an Ethernet connection as indicated by the green box at the bottom of the dialog.
Torque Sensor Voltage displays the electrical current, in milliVolts, corresponding to the current position of the valve.
The numbers tend to be smaller (more negative) while closing and larger (more positive) while opening.
Calibrated Torque displays the percentage open or closed at which the valve is currently positioned.
The Calibration Values are set by opening and closing the valve, and by setting it to 30% open or closed. At each valve setting, press the Set button to record the number of milliVolts corresponding to the valve position.
Once the values are set for the physical valve, they can be saved to a file by pressing Save to File. In the case of changing out the valve's electronics, the calibration settings can be read from that file by pressing the Load From File button. Once the values are set for the physical valve, they can be uploaded to the connected valve by pressing Save To Hardware.
Once a valve is calibrated, Design Pad will query the valve for its calibration points when Load From Hardware is pressed.
When Calibrate Pressure is selected, the dialog below is displayed. The Gauge Pressure tab is shown first.
The current values are displayed at the top of the dialog. Fluid pressure at sensor A and B are displayed in milliVolts, along with the calibrated pressure in pounds per square inch and the percentage of the valve's maximum pressure load associated with the current reading The difference between those readings in displayed below the raw current measurements
The rest of the dialog allows for determining the pressure sensor measurements at specific pressure increments . Each sensor's measurement at the flow rate is determined and its calibrated voltage saved by pressing the corresponding Set button. These values can be saved and read from a file as described for torque calibration values described above. The calibration vales can also be read from or written to the valve electronics.
The pressure labels change for fifty and one hundred percent capacity based on the valve type installed.
Selecting the Differential Pressure tab shows this dialog:
Connect the valve to a fluid source to calibrate its differential pressures, the difference between measurements at sensor A and B, at each flow setting. As each range is reached its Set button becomes active. Set the calibration value for each pressure value and press Save to Hardware to upload the values to the valve. Press Save to File to create an archive for use if the electronics are replaced. Load the file's values by pressing Load from File. Query the current calibration settings from the hardware by pressing the Load from Hardware button.
