MICON 500C Electronic Sequencing
34
234AY00.INS R06
Computer Installation Guide
8.3
SOFTWARE
This system employs algorithms based on ideal gas law equations to predict an end-of-fill final
pressure. Variables such as the dynamic gas pressure, ambient temperature and gas temperature are
utilized. The system basically functions as follows:
1.
When each fill is authorized, the main flow and high bank valves are opened, recording
the dispensed amounts.
2.
After 4 seconds, both valves are closed.
3.
After waiting an additional 4 seconds for the pressure to stabilize, the initial pressure
transducer reading is recorded.
4.
The main flow valve is again opened and the fill continues as per normal. The final fill
pressure is monitored throughout the sale.
The final fill pressure is limited to the absolute pressure hard value. The absolute pressure is
calculated as 1.2 times the operating pressure:
OPERATING PRESSURE
MULTIPLICATION FACTOR
ABSOLUTE PRESSURE: FINAL FILL
PRESSURE CANNOT EXCEED THIS
VALUE.
3000 psig
multiply by 1.2
3600 psig
3600 psig
multiply by 1.2
4320 psig
At the final fill pressure, the fill terminates, regardless of the state of the fill. However, the restart
timeout mechanism will be allowed to take its course, just in case the pressure transducer reading is
falsely high and settles below the target fill valve pressure. See section 8.5 - Restart Timeout & Noise
Blanking, page 35.
The initial pressure referred to in step 3 above (i.e., after valves have closed and pressure stabilized) is
used for two functions:
Ø
First, if it exceeds 90% of the predicted final target fill pressure, the fill is not allowed to
begin.
Ø
Initial pressure is also used by the main algorithm to predict falsely high pressure readings
due to compression heating of cylinder gas, and to provide an adjustable correction factor to
compensate for this.
TABLE 11 – ABSOLUTE PRESSURE
