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

1.7

Scaling Function

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. The program for scale conversion can be omitted.
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.)
When the relation between the set upper limit value and lower limit value is Scaling lower limit value > Scaling upper limit
value, the scale conversion can be performed according to a negative slope.
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 analog output range.
■When the factory default setting is used for the analog 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 analog 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 equations.
■When the factory default setting is used for the output range
• When the voltage is 1 to 5V or 0 to 5V and the current is 4 to 20mA or 0 to 20mA
Digital value used for D/A
conversion
• When the voltage is -10 to 10V
Digital value used for D/A
conversion
■When the user range setting is used for the output range
Digital value used for D/A
conversion
Item
D
X
S
H
S
L
32000
× (D
=
- S )
X L
S - S
H L
64000
× (D
- S ) - 32000
=
X L
S - S
H L
32000
× (D
=
- S )
X L
S - S
H L
Description
Digital value
Scaling upper limit value
Scaling lower limit value
1 FUNCTIONS
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1.7 Scaling Function
1