MICON 500C Electronic Sequencing
35
234AY00.INS R06
Computer Installation Guide
8.4
END-OF-FILL DETERMINANTS
Following is a list of conditions which can terminate a fill (i.e., reset the register):
1.
The pressure at the dispenser transducer has reached the predicted final fill pressure,
and the fill terminates under normal operating conditions.
The fill is terminated once
the restart timeout times out.
2.
The absolute pressure is reached.
If the final fill pressure reaches this pressure, the fill
must be terminated regardless of how full the vehicle actually is. However, this is not an
emergency condition, and the restart timeout is allowed to take place, to see if the pressure
again drops below the absolute value. If it does, then the restart timeout will allow the fill to
resume. Otherwise, the fill fully terminates without any special annunciations.
3.
The pressure switch triggers.
Where the pressure switch PSI is installed, it is set for a
switching pressure equal to the absolute pressure value. As can be seen, it serves as a
mechanical backup for the pressure transducers.
As in #2 above, if the final fill pressure reaches the absolute pressure, the fill must be
terminated regardless of how full the vehicle actually is. This is not an emergency condition,
and the restart timeout is allowed to take place, to see if the pressure again drops below the
absolute value. If it does, then the restart timeout will allow the fill to resume. Otherwise,
the fill fully terminates without any special annunciations.
4.
If the customer turns OFF the handle switch
, the fill is considered terminated
immediately, with no restart timeout.
5. ‘
No flow’ timeout.
This feature is settable using the INFO-PAC transmitter, and controls
the length of time MICON 500C keeps motor and solenoid valve ON if a sale is in progress
but there is no product flow being registered. It can be set from 15 seconds to 4 minutes, 15
seconds. See INFO-PAC MICON 500C Programming Manual (software version: 3.0).
6.
If the initial vehicle cylinder pressure exceeds 90% of the final target pressure as
calculated
, a fill is not permitted to proceed, as the vehicle is too close to full to assure a
safe end-of-fill.
7.
Faults or alarms.
The MICON hardware or software may generate an internal or receive
an external fault or alarm. Alarm shutdown triggers are identified separately in section 8.10
– Alarms (Table 12), page 40, with appropriate reset actions. Alarm triggers include the
Excess Flow and Excess Fill features, settable using the INFO-PAC transmitter.
8.5
RESTART TIMEOUT & NOISE BLANKING
In certain common situations, the dispenser pressure transducer may temporarily see a pressure higher
than the actual pressure of the vehicle cylinder being filled. In this case, the fill will stop when the
pressure-temperature compensation system has determined a normal end of-fill, as described in
scenarios 1, 2, and 3 above. The fill will then be given a chance to restart and continue if the static
pressure at the transducer (which is actually the static vehicle cylinder pressure) settles or falls below
the end-of-fill pressure. This is accomplished by two time delays, which are preset in the INFO-PAC:
the
noise blanking delay
and the
restart timeout delay
.
