Watlow D4T Data Logger
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Chapter 5 Function Reference
Math Errors (cont .)
Function
Error Condition
Result
Square
Root
X has an error
The output is equal to the offset and has an
error.
X is less than zero
The output is equal to the offset and has an
error.
Sample
and Hold
IN has an error HOLD is off
The output’s value and error follow IN.
IN has an error
HOLD is on with no error
The output value and error status are the
same as IN at the time HOLD turned on.
HOLD has an error
The output’s value and error follow IN.
Pressure to
Altitude
X has an error
The output’s value is calculated as usual and
has an error.
Dew Point T, RH or both have errors
The output is equal to the offset and has an
error.
Process Value
Use this block to produce a conditioned analog signal based on up to four analog signals and
one digital signal. A filter and offset may be applied to the function’s output. This block is
found in the Function Block Diagram editor’s Library. Within the Library, the number of these
blocks available is shown in parenthesis and that number is determined by the data logger
part number. The type of conditioning performed by the process block depends on the setting
of the Function parameter. These options for the Function parameter are described in detail
in the following sections:
: the output follows the filtered input plus the offset.
: automatically switches to the next of up to three alternate inputs when a sen-
sor fails.
: calculates the average of up to four inputs.
: gradually transitions from one input to another over a user-defined range.
: calculates relative humidity based on two temperature measurements.
: selects one of two analog inputs with a digital input.
: subtracts one input from another.
: divides one input by another.
: sums up to four inputs.
: computes the product of up to four inputs.
: calculates the absolute value of one input subtracted from another.
: outputs the lowest of up to four inputs.
: outputs the greatest of up to four inputs.
: calculates square root of an input.
: calculates the relative humidity based on the input from an un-
compensated relative humidity sensor and a temperature measurement.
: calculates the standard distance above sea level based on an atmospher-
ic pressure.