Vaisala FD12P - Manual (Page 92)

User's Guide _______________________________________________________________________
92 ______________________________________________________ M210296en-A
When you type
ACAL
↵ ↵↵ ↵
the command gives, for example, the following output:
MEASURED CURRENT (mA) 22.16
MEASURED CURRENT (mA) 4.52
Data Scaling
The FD12 scales the visibility value to a binary number for the DAC
( = DACBITS) so that the minimum visibility corresponds to the
4 mA-calibrated value and maximum visibility to the 20 mA-
calibrated value.
In linear mode:
DACBITS = (visibility - min visibility) × scale 1 + scale 0
In logarithmic mode:
DACBITS = (ln(visibility) - ln(min visibility)) × scale 1 + scale 0
If visibility is less than minimum visibility then
DACBITS = bits4mA = scale 0
If visibility is more than maximum visibility then
DACBITS = bits 20mA
Hardware Check
The DAC bit value from 0 to 4095 can be given as a parameter. The
value does not change until you press ESC. When the DAC command
has been given without a parameter, the analog output sweeps slowly
from 0 to maximum and from 0 until you press the ESC key.
For example:
DAC 800
↵ ↵↵ ↵