17 paroscientific "t" series pressure transducer – Campbell Scientific CR10X Measurement and Control System User Manual
Page 104
SECTION 7. MEASUREMENT PROGRAMMING EXAMPLES
7-20
04:
Z=X+F (P34)
1:
1
X Loc [ Temp ]
2: -24
F
3:
3
Z Loc [ Temp_Comp ]
05:
Z=X*F (P37)
1:
3
X Loc [ Temp_Comp ]
2:
-.0698
F
3:
3
Z Loc [ Temp_Comp ]
06:
Z=X+Y (P33)
1:
3
X Loc [ Temp_Comp ]
2:
2
Y Loc [ Pressure ]
3:
2
Z Loc [ Pressure ]
07:
IF (X<=>F) (P89)
1:
5
X Loc [ Cmpile_Ck ]
2:
1
=
3:
0
F
4:
30
Then Do
08:
Z=X+F (P34)
1:
2
X Loc [ Pressure ]
2:
47.23
F
3:
4
Z Loc [ Offset ]
09:
Z=F (P30)
1:
1
F
2:
0
Exponent of 10
3:
5
Z Loc [ Cmpile_Ck ]
10:
End (P95)
11:
Z=X-Y (P35)
1:
4
X Loc [ Offset ]
2:
2
Y Loc [ Pressure ]
3:
6
Z Loc [ Distance ]
7.17 PAROSCIENTIFIC "T" SERIES
PRESSURE TRANSDUCER
The Paroscientific "T" series transducer has two
resonating quartz crystals that output frequency
signals for temperature and pressure. The
pressure output requires temperature
compensation. Instruction 27 measures the
outputs and returns period in microseconds
(refer to Table 7.17-1).
TABLE 7.17-1 Period Averaging Inst. 27
PARAM.
DATA
NUMBER
TYPE
DESCRIPTION
01:
2
Repetitions
02:
2
Gain/output option
03:
2
Single Ended Input
Channel
04:
4
# Cycles to measure
05:
4
Time out (0.01 sec, at
least the maximum
duration of the # of cycles
specified + 1 1/2 cycles.)
06:
4
Destination input location
07:
FP
Multiplier
08:
FP
Offset
GAIN/OUTPUT OPTION, PARAMETER 2
The nominal pressure frequency range is 32 to
42 kHz over the stated pressure range (period
of 3.1
∗10
-5
to 2.4
∗10
-5
). The nominal
temperature frequency is 172 kHz,
±
50 ppm/
°C
(period of 5.8
∗10
-6
). The gain/output option
(Parameter 2) is based on the maximum input
frequency. For the stated temperature and
pressure frequency ranges, the gain codes are
3 and 4 (refer to Table 7.17-2). Codes 1 and 2
are not used with Paroscientific transducers.
For period, the output option is 0.
NOTE: The 172 kHz signal is greater than
the specified maximum of 150 kHz.
Variability in the amplifier forces the 150 kHz
specification. Selecting components allow
frequencies up to 200 kHz to be measured
accurately. Consult CSI if, as in this example,
your application requires a higher frequency.
TABLE 7.17-2 Input Frequency Gain Codes
Range
Peak to Peak Volts
Maximum
Code
Required @ Max. Freq.* Frequency
1
2 mV
8 kHz
2
3 mV
20 kHz
3
12 mV
50 kHz
4
2 V
150 kHz
0x
Output period in microseconds
1x
Output frequency in kHz
where x is range code
*
AC voltage; must be centered around
CR10X ground.