Campbell Scientific CR1000 Measurement and Control System - Manual (Page 429)

Section 10. Troubleshooting
429
10.3.4.2 Floating-Point Math, NAN, and ±INF
Table Math Expressions and CRBasic Results
(p. 429)
lists math expressions, their
CRBasic form, and IEEE floating point-math result loaded into variables declared
as FLOAT or STRING.
10.3.4.3 Data Types, NAN, and ±INF
NAN and ±INF are presented differently depending on the declared-variable data
type. Further, they are recorded differently depending on the final-storage data
type chosen compounded with the declared-variable data type used as the source
(table Variable and FS Data Types with NAN and ±INF
(p. 429)
). For example, INF
in a variable declared As LONG is represented by the integer -2147483648.
When that variable is used as the source, the final-storage word when sampled as
UINT2 is stored as 0.
Table 111. Math Expressions and CRBasic
Results
Expression
CRBasic
Expression
Result
0 / 0 0 / 0 NAN
∞ - ∞ (1 / 0) - (1 / 0) NAN
(-1) ∞ -1 ^ (1 / 0) NAN
0 * -∞ 0 * (-1 * (1 / 0)) NAN
±∞ / ±∞ (1 / 0) / (1 / 0) NAN
1
∞ 1 ^ (1 / 0) NAN
0 * ∞ 0 * (1 / 0) NAN
x / 0 1 / 0 INF
x / -0 1 / -0 INF
-x / 0 -1 / 0 -INF
-x / -0 -1 / -0 -INF
∞ 0 (1 / 0) ^ 0 INF
0 ∞ 0 ^ (1 / 0) 0
0
0 0 ^ 0 1
Table 112. Variable and FS Data Types with NAN and ±INF
Final-Storage Data Type & Associated Stored Values
Variable
Type
Test
Expressio
n
Public / Dim
Variables FP2 IEEE4 UINT2 UNIT4 STRING BOOL BOOL8 LONG
As FLOAT 1 / 0 INF INF1 INF1 655352 4294967295 +INF TRUE TRUE 2,147,483,647
0 / 0 NAN NAN NAN 0 2147483648 NAN TRUE TRUE -2,147,483,648
As LONG 1 / 0 2,147,483,647 7999 2.147484E09 65535 2147483647 2147483647 TRUE TRUE 2,147,483,647