Campbell Scientific CR7 Measurement and Control System User Manual
Page 97
SECTION 9. INPUT/OUTPUT INSTRUCTIONS
9-7
PAR.
DATA
NO.
TYPE
DESCRIPTION
01:
2
Repetitions
02:
2
Range code (Table 9-1)
03:
2
Analog card number
04:
2
Single-ended channel number
for first measurement
05:
2
TC type code (Table 9-3)
06:
4
Reference temperature
location. (When indexed (--)
this is incremented with each
rep.)
07:
4
Input location number
08:
FP
Multiplier
09:
FP
Offset
Input locations altered: 1 per repetition
*** 14 THERMOCOUPLE ***
TEMPERATURE, DIFFERENTIAL
MEASUREMENT
FUNCTION
This instruction calculates the thermocouple
temperature for the thermocouple type selected.
The instruction specifies a DIFFERENTIAL
VOLTAGE MEASUREMENT (Section 13.2) on
the thermocouple, adds the measured voltage
to the voltage calculated for the reference
temperature relative to 0 oC, and converts the
combined voltage to temperature in oC. The
differential inputs are briefly shorted to ground
prior to making the voltage measurement to
insure that they are within the common mode
range. (Section 13.4)
Table 9-3 gives the thermocouple type codes
for Parameter 5, the option of skipping every
other channel applies only to Instruction 13.
The reference temperature location will be
incremented by one each repetition if C is keyed
before entering Parameter 6. When this option
is exercised, two minus signs (--) will appear as
the right most characters of the display.
A multiplier of 1 and an offset of 0 yields
temperature in degrees C.
PAR.
DATA
NO.
TYPE
DESCRIPTION
01:
2
Repetitions
02:
2
Range code (Table 9-1)
03:
2
Card number
04:
2
Beginning channel
05:
2
TC type code (Table 9-3)
06:
4
Reference temperature
location. (When indexed (--)
this is incremented with each
rep.)
07:
4
Input location number
08:
FP
Multiplier
09:
FP
Offset
Input locations altered: 1 per repetition
*** 16 TEMPERATURE FROM ***
PLATINUM R.T.D.
FUNCTION
This instruction uses the result of a previous
RTD bridge measurement to calculate the
temperature according to the DIN 43760
specification adjusted (1980) to the pending
International Electrotechnical Commission
standard. The range of linearization is -200 oC
to 850 oC. The error in the linearization is less
than 0.001 oC between -200 and +300 oC, and
is less than 0.003 oC between -180 and
+830 oC. The error (T calculated - T standard)
is +0.006o at -200o and -0.006 at +850 oC.
The input must be the ratio R/R0, where R is
the RTD resistance and R0 the resistance of
the RTD at 0 oC.
A multiplier of 1 and an offset of 0 yields
temperature in degrees C.
PAR.
DATA
NO.
TYPE
DESCRIPTION
01:
2
Repetitions
02:
4
Input location number of
(R/Ro)
03:
4
Input location number of
result
04:
FP
Multiplier
05:
FP
Offset
Input locations altered: 1 per repetition
*** 17 TEMPERATURE OF INPUT PANEL ***
FUNCTION
This instruction measures the temperature in
oC of the specified analog input card with RTD
(Model 723-T).
PAR.
DATA
NO.
TYPE
DESCRIPTION
01:
2
Analog card number
02:
4
Input location number
Input locations altered: 1