Operator`s manual

SECTION 7. MEASUREMENT PROGRAMMING EXAMPLES
7-12
The manual for the 101 Probe gives the
coefficients of the 5th order polynomial used to
convert the output in millivolts to temperature (E
denotes the power of 10 by which the mantissa
is multiplied):
C0 -53.7842
C1 0.147974
C2 -2.18755E-4
C3 2.19046E-7
C4 -1.11341E-10
C5 2.33651E-14
The 21X will only allow 5 significant digits to the
right or left of the decimal point to be entered
from the keyboard. The polynomial cannot be
applied exactly as given in the 101 manual. The
initial millivolt reading must be scaled if the
coefficients of the higher order terms are to be
entered with the maximum number of significant
digits. If 0.001 is used as a multiplier on the
millivolt output, the coefficients are divided by
0.001 raised to the appropriate power (i.e.,
C0=C0, C1=C1/0.001, C2=C2/.000001, etc.).
With this adjustment, the coefficients entered in
Parameters 4-9 of Instruction 55 become:
C0 -53.784
C1 147.97
C2 -218.76
C3 219.05
C4 -111.34
C5 23.365
FIGURE 7.15-1. 101 Thermistor Probes
Connected to 21X
PROGRAM
01: P4 Excite,Delay,Volt(SE)
01: 5 Reps
02: 5 5000 mV slow Range
03: 1 IN Chan
04: 1 Excite all reps w/EXchan 1
05: 10 Delay (units .01sec)
06: 2000 mV Excitation
07: 1 Loc :
08: .001 Mult
09: 0 Offset
02: P55 Polynomial
01: 5 Reps
02: 1 X Loc
03: 1 F(X) Loc :
04: -53.784 C0
05: 147.97 C1
06: -218.76 C2
07: 219.05 C3
08: -111.34 C4
09: 23.365 C5
7.16 MEASURING 107 TEMPERATURE
PROBE WITH 60 HZ REJECTION
The 107 temperature probe is normally
measured with Instruction 11 which uses the
same measurement sequence as Instruction 5
with a fast integration voltage measurement.
The fast integration does not reject 60 Hz noise.
In environments where 60 Hz is a problem, the
107 probe can be measured with Instruction 5
using the slow integration time.
A multiplier of 800 in Instruction 5 is used to
scale the voltage measurement for the
polynomial Instruction 55 which is used to
convert the voltage measurement to
o
C.