
45
S
Signed form for the commands (
P3, P4
) using the binary format. This yields a 7 bit binary
device address and a sign + 16 bit magnitude for data. This allows up to 60,000 counts in the
pressure A/D conversion cycle. If the FS value is set above 60,000 counts, then only four
significant digits will be displayed instead of five.
................................................................................................................
O
When this parameter is sent to the HPB and the power control line is either floating or held at 5V,
the majority of internal HPB circuitry is immediately turned
O
ff and the HPB enters micro-power
state. If the power control line is at ground (0V) when the command is sent, the HPB will not enter a
micro-power state until the power control line is subsequently returned to 5V. Normal operation is
restored by momentarily grounding the power control pin. The OP=O parameter is not stored in
eeprom. Also,
OP=O
is not accepted when
OP=P
is active.
P
This parameter allows the HPB micro-power state to be controlled with the
P
ower control line.
Holding the power control line at 0V enables normal operation. When the power control line is
raised to 5V, the HPB immediately enters the micro-power state.
X
No watchdog time enabled.
W
W
atchdog time enabled to reset the HPB if it should stop for ~50 msec.
Note:
if the
IC
command is
set to any value other than
IC=0
, then the
OP=W
command will not set and cause a
RS
command
error condition.
P=
Production Date
The
P
roduction date command reads the factory set HPB manufactured date with format mm/dd/yy. If the response
has an ! character instead of =, there was an EEPROM parity error.
Inquiry:
*dd
P=
P1
Pressure, Single, ASCII Format
The
P1
command requests a temperature compensated pressure (CP) reading in ASCII format. Refer to Table 4.2
for default decimal placement and significant digits. When in a ring network configuration and this command has a
group or global address (
*9d
), it is a sequential request command and the
OP=A
or
U
all or changes only parameter
controls the output. If this command is executed while a
P2, P4, T2,
or
T4
command is executing, then one ASCII
pressure reading is transmitted and the continuous command resumes operation.
Note:
If a group or global
P1
or
P3
command is sent and the pressure reading for that integration cycle has
been read before, then the HPB will not send any pressure value.
Note:
The HPB continuously integrates and calculates pressure and temperature readings. When this command
is received, the latest available reading is transmitted if there is sufficient digital output buffer space. A
group or global address command echo of
*9dP1!
indicates that digital buffer space was not available for
one of the addressed HPBs.
Inquiry:
*dd
P1
A response of
#ddCP!0.0000
either indicates the pressure is at zero and a temperature over/under range occurred or
there is an EEPROM parity error. Check
RS
for specific error. If a parity error occurred, then send a
*ddIN=RESET
command or cycle the power off and on.
A response of
#01CP=..
indicates that no pressure reading is available yet. Try again. This response can be a result
of a
P1
request after a
DU, BP
(parity change), or
ID
action command or during the power-up cycle before valid
data is available.