Honeywell HPA, Руководство пользователя, Страница: 53 / 68

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p = 6 EEPROM parity/control checksum error
p = 7 EEPROM parity/characterization/control error
p = 8 EEPROM parity error for A=, B=, C=, D=, M=, P=, S=, and start-up header response.
q = 0 No command error
q = 1 Command error
r = 1 Digital communications framing error
r = 2 Digital communications parity error
r = 3 Both framing and parity digital communications errors
s = 0 No temperature or pressure range errors
s = > Over temperature condition
s = < Under temperature condition
s = + Over pressure condition (>1% over FS)
s = - Under pressure condition (>1% under lower limit)
s = B Microprocessor bandwith warning
s = G Internal signal noise detected, may indicate a grounding problem
s = W Watchdog timer interrupt occured or an IN=RESET was executed
A pressure-over-range error condition will occur when the applied pressure is greater than or equal to 1% of full scale
(FS) above the FS limit. For example, if the pressure applied to a 17.6 psia unit is >17.776 psia, then an over range error
condition is set. Similarly, an under range condition occurs when the applied pressure is greater than or equal to
1% FS below the minimum limit. If the temperature exceeds the limit values (-40 and 85 °C), then the over/under
temperature error flag is set. The temperature output reading will remain at the limits. If there had been an over and
an under-range condition, then the first RS inquiry reply will be “000+”, the second will be “000-” and the third
will be “0000”.
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 integration cycles stop.
This can be overridden by executing two RS commands consecutively, which clears the error indications.
Pressure and temperature 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 HPB’s which have at least one error condition will respond. Replies
are in sequential 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.
S= Serial Number
The S erial number command reads the factory set HPB serial number. If the response has an ‘!’ character instead
of ‘=‘, there was an EEPROM parity error.
Inquiry: *dd S=
Multi-Drop type only
In multidrop bus configuration only this command must be used to identify a HPB for address assignment.
Command *99S= ssssssss, where ssssssss is the 8 character serial number of the HPB (in this case the leading zeros
of the serial number must be used because the identification match is made on all 8 ASCII characters—not the
decimal value of the serial number), identifies the HPB for identification address assignment. The address
assignment is then performed by a *99ID nn command, where nn is the address.
Note: If two HPB units on a multi-drop bus have the same ID then you can use the sequence
below to re-assign ID numbers