Yokogawa PC-Based MX100 User Manual
Page 48
2-34
IM MX180-01E
Explanaton
Computaton Overvew
You can enter computation equations using the constants, operators, and functions
described below. The computed results can be displayed and recorded (saved) as
computed data. Computation allows you to determine the average/maximum/minimum
of a specified channel on a specified date/time, or output events (start/stop record, reset
time, etc.) under specified conditions. The number of available computation channels is
60 (channel numbers 99001 to 99060), and the number of characters that can be used in
the equation is 127.
Constants
The following three types of constants can be used.
• User-defned constants
A constant can be assigned to an arbitrary string (name). You can set up to sixty user-
defined constants. Set the Name of the constant using a string (up to ten characters)
that is not used by predefined constants or functions. They are not case-sensitive.
The precision and range of the constant values are the same as the single-precision
floating point format (32 bits, negative values: –3.4028235E+38 to –1.401298E–45,
and positive values: 1.401298E–45 to 3.4028235E+38).
• Predefned constants
The five strings below are used for predefined constants. They are not case-sensitive.
•
NaN:
Represents an invalid value or error value. For a description of the
computed result when NaN is used in the computation, see “Notes on
Computation” in this section.
•
POver: Represents +Over (positive overrange). The expression POver > x is
satisfied for any arbitrary value x.
•
MOver: Represents –Over (negative overrange). The expression MOver < x is
satisfied for any arbitrary value x.
•
Pi:
Represents the ratio of the circumference (3.14...).
•
e:
Represents the base of the natural logarithm (2.718...).
• Numerc constants
Numeric values that are written directly in the equation. They are expressed in the
following form.
[digits][.digits][{d|D|e|E}[digits]]
Example: 1.0d+1 represents 10.0.
Channel Numbers
Channel numbers can be used to specify the
channels). The channel number is specified using five digits, the unit number in the
highest two digits and the channel number within the unit in the lowest three digits. On
the MX100 Standard Software, measurement channels are specified using 00001 to
00060 (1 to 60 are also allowed). Measurement channels are specified using 990001 to
99060.
Tag Numbers
Tag numbers can be used to specify the
channels). The tag numbers are enclosed in double quotation marks as in “TagNo.00001”
They are case-sensitive.
Note
If the same tag number is specified on multiple channels, proper operation is not guaranteed.
2.5 Settng Computatons (Settng the Computaton Channels)