Scaling Function - Mitsubishi Electric MELSEC iQ-R Series User Manual

1.7

Scaling Function

Normal
This function performs the scale conversion on digital values within a specified range between a scaling upper limit value and
a scaling lower limit value. This function helps reduce the time taken for creating a scale conversion program.
Operation
The scale conversion is performed for the set 'CH1 Digital value' (Un\G460) using 'CH1 Scaling upper limit value' (Un\G504)
and 'CH1 Scaling lower limit value' (Un\G506), and the value after the scale conversion is used for the D/A conversion. (In the
scale conversion, values after the decimal point are rounded off.)
Concept of scaling setting
The necessary settings for the scaling lower limit value and scaling upper limit value depend on whether the factory default
setting or the user range setting is used for the output range.
■When the factory default setting is used for the output range
• For the scaling upper limit value, set a value corresponding to the upper limit value of the set analog output value.
• For the scaling lower limit value, set a value corresponding to the lower limit value of the set analog output value.
■When the user range setting is used for the output range
• Set a value corresponding to the gain value for the scaling upper limit value.
• Set a value corresponding to the offset value for the scaling lower limit value.
Calculating the scaling value
For D/A conversion, the scaling value is calculated based on the following calculation formulas.
■When the factory default setting is used for the output range
• When the voltage is 1 to 5V or 0 to 5V, and current is 4 to 20mA or 0 to 20mA:
32000
D = × (D - S
X L
S
S - S
H L
• When the voltage is -10 to 10V:
64000
D =
× (D - S ) - 32000
X L
S S - S
H L
■When the user range setting is used for the output range
32000
D = × (D - S
X L
S S - S
H L
Item
D
S
D
X
S
H
S
L
• If the relation between the values is the scaling lower limit value > the scaling upper limit value, the scale
conversion can be performed according to a negative slope.
• Set the scaling with the condition "Scaling upper limit value  Scaling lower limit value".
1 FUNCTIONS
28
1.7 Scaling Function
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Description
The digital value used in the D/A conversion
Digital value
Scaling upper limit value
Scaling lower limit value