Campbell Scientific CR10 CR10 Measurement and Control - Page 105

SECTION 7. MEASUREMENT PROGRAMMING EXAMPLES CR1 O CONNECTIONS r CABLING r USER I STANDARD CABLE W/ SENSOR I SINGLE ENDED INPUT AG \n, 12V SINGLE ENDED INPUT AG PA,R'TO,S' CIENTIFIC SERIIS FfGURE 7.17-1. CRl0/Paroscientific "T" Series Transducer Wiring Diagram Subroutine 1, which loads the coefficients into input locations, is called only on the first execution following program compilation. The temperature frequency is read on singleended Channel '12 and pressure is measured on single-ended Channel 1. Temperature,To, D and C are computed in Subroutine 2 using a generalized fourth order polynomial equation. The form of the equation is F(x) = Us + U(M1 + U(M2 + U(M3 + UM/)). This form provides faster execution and greater accuracy of the floating point math. "Ms..4" represents coefficients 0 through 4, and U is defined above. With five coefficients, To is the only parameter requiring a fourth order polynomial. To maintain the fourth order format, zero value "dummy" coefficients are plugged in where required tor the temperature, D, and C coefficients. lnstructions to output the readings to Final Storage are not included in this example. "1 01: 60 01: P89 01: 42 Q2: 1 03: 0 o4'. 1 02: 01: 02: 03: o4: 05: 06: 07: 08: P27 1 4 12 9000 6 10 1 0 03: 0't: 02: 03: 04: 05: 06: 07: 08: P27 1 3 1 5000 16 11 1 0 Table 1 Programs Sec" Execution Interval lf XF X Loc CMPILE CK F Gallsubroutine 1 Period Average (SE) Rep lnput gain=1 lN Chan No. of Cycles Time Out (units=.01 sec) Loc [:UT us ] Mult Offset Period Average (SE) Rep lnput gain=10 lN Chan No. of Cycles Time Out (units=.01 sec) Loc [:TAU us ] Mult Offset 7-21