Honeywell PPT User Manual page 67

The maximum pressure reading is 105 percent of FS. This limit varies slightly from device to device
but will continue to display the out-of-range indicator ("!" in place of "=") until the pressure drops
below 101 percent of FS
Note: In the unlikely event of EEPROM checksum errors, the temperature and pressure integra-
tion cycles stop. This can be overridden by executing two RS commands consecutively, which clears
the error indications. Pressure, temperature and DAC readings can then be taken; however, the
readings may not be correct. Also the fourth error indicator is prioritized in the order shown. When
the RS command is issued with a group or global address (sequential mode), only PPTs which have
at least one error condition will respond. Replies are in sequential RS-232 bus loop connection order,
followed by the return of the RS command.
Out-of-range temperature has display precedence over out-of-range pressure, which in turn has
precedence over microprocessor bandwith warning, which is followed in precedence by noisy signal
ground warning. The indication is cleared only if the condition no longer exists. If temperature out-
of-range, pressure out-of-range, and microprocessor bandwidth warning all existed, then with
successive RS commands, the first command would show the temperature condition, the second
command would show the pressure condition, the third command would show the bandwidth
warning, and the fourth command would show no error.
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