Yokogawa PC-Based MX100 - Manual (Page 56)

2-42 IM MX180-01E
• The value of NaN is considered true for the &&, ||, ^^, and ! operators.
• For all other computations
Computation is performed taking NaN as a value. Thus, NaN is returned as the
computed result.
• The numeric value display on the Monitor screen displays INVALID.
• Handling when the value of a measurement channel is ±Over (exceeding the upper
and lower limits of the measurement range)
If the measured value used in the reference function or TLOG function is ±Over,
computation continues in one of two ways. Select the handling method using the
Calculate +Over/–Over as the MAX/MIN value of a range check box.
• Continue the computation as ±Over.
• Continue the calculation by setting ±Over to the maximum or minimum value of the
measurement range of the specified channel.
Use the following values as the maximum and minimum value of the measurement
range.
• DC voltage:
±10% of the range
Example: 6 V range
+OVER: +6.6 V
–OVER: –6.6 V
• Temperature: ±10ºC of the rated measurement range
However, 0 K and 10 K for KpVsAu7Fe and J263B.
• Linear scaling: Maximum and minimum values of the scale corresponding to ±10%
of the measurement span
However, ±32000 when the scale value exceeds ±32000.
Example 1: When the measurement span is set to ±1 V and the scale is set to
±10000 at 2 V range
+OVER: +22000
–OVER: –22000
Example 2: When the measurement span is set to ±2 V and the scale is set to
±30000 at 2 V range
+OVER: +32000
–OVER: –32000
To suppress ±Over from occurring in an arbitrary computation, use the limit function (see
“Arithmetic Functions” under “Explanation” in this section).
• Alarms for computation using the Alarm() function
The alarm corresponding to the current value is used for the alarm of a measurement
channel.
The alarm corresponding to the current value is used for the alarm of a computation
channel. However, for computation channels that have not yet computed the current
value, the alarm corresponding to the previous value is used.
Settng the Computaton Span
This section provides an explanation of the span of transmission output for the analog
output and PWM output modules.
• MATH channel range over
The upper and lower limits for the display of the monitor screen and other items. The
MATH span setting range is as shown below depending on the decimal place. If the
computed results fall outside of the MATH span setting range, they are displayed on
screen as plus over or minus over data.
Decmal Place MATH span settng range Decmal Place MATH span settng range
0 –9999999 to 99999999 3 –9999.999 to 99999.999
1 –999999.9 to 9999999.9 4 –999.9999 to 9999.9999
2 –99999.99 to 999999.99
2.5 Settng Computatons (Settng the Computaton Channels)