Section 5
Page 5 - 18
HA243821
Issue 5 Mar 98
MODEL 346 INSTALLATION AND OPERATION MANUAL
5.6.2 MATHS FUNCTIONS (Cont.)
Average
Single-point cumulative average. The value of input 1 is sampled every ‘input 2’ seconds (mini-
mum 5 seconds; maximum 32767 seconds). The sample is then added to the cumulative total and
divided by the cumulative number of samples.
Since the number of samples is limited to 65536 (91 hours if at 5 seconds per sample), this aver-
age is most useful for a batch rather than as a continuous measurement. The function resets (by
Action Equation (see 3.4) or after 65536 samples) to the current input value.
Note...
The input filter (channel menu, section 4.8) is, in effect, a running average with the number of samples held
continuously equal to the number of filtering seconds.
PolynomialThird order polynomial curve fit: A+BX+CX
2
+DX
3
, where:
Input 1 = variable (X)
Input 2 = constant A
Input 3 = constant B
Input 4 = constant C
Input 5 = constant D
Log 10
Log to the Base 10: Output is input 2 x log
10
input 1 where, input 1 is the variable, and input 2 is a
scaling factor.
Power 10
Power of 10: Output is input 2 x 10
input 1
where input 1 is the variable and input 2 is a scaling factor.
Input 1 must lie b30 and -30, or else the output is 0000.0
Flow, Sq. Rt Square Root Mass Flow (AGA 3 Gas Flow):
where:
Input 1 = (C’) universal scaling constant.
Input 2 = (h
w
) differential pressure in inches of water.
Input 3 = (pf) static pressure in PSI(A).
Input 4 = (Tf) flow temp in degrees Rankine (˚F + 460)
Input 5 = compressibility correction
Should Input 4 or Input 5 ever be 0.0, the DV value will limit at 99999.
Flow, Linr.
Linear Mass Flow (AGA 3 Gas Flow):
where:
Input 1 = (C’) universal scaling constant.
Input 2 = (hw) differential pressure in inches of water.
Input 3 = (pf) static pressure in PSI(A).
Input 4 = (Tf) flow temp in degrees Rankine (˚F + 460)
Input 5 = compressibility correction
Should Input 4 or Input 5 ever be 0.0, the DV value will limit at 99999.
Output
=
Input1x
Input2 xInput3
Input 4 xInput5
Output
=
Input1x
Input2 xInput3
Input 4 xInput
