Mitsubishi Electric FX2N-2AD User Manual page 4

7. Adjustment of offset and gain
7.1 Change in input characteristic
At shipment, 0 to 4000 range is selected for 0 to 10V DC input.
When using an FX
2N
adjust the offset and gain.
The module does not allow different input characteristics for two channels.
Set analog values within the range specified in the table below when changing the input characteristic.
Range of input characteristic
Analog value when digital value is 0
Analog value when digital value is 4000
Resolution changes depending on the set value when the input characteristic changes accordingly.
Example: Resolution becomes (5 - 0V)/4000=1.25mV at voltage input 0 to 5V/0 to 4000.
Integrated accuracy does not change. (Voltage input
7.2 Adjustment of the input characteristic
The adjustment of the offset and gain values sets a digital equivalent to the analogue data.
(The "POT" requires 18 revolutions to move between MIN and MAX setting.)
Voltage input
+ +
Voltage
V
generator
- -
COM
*1 The digital value increases if the volume is turned clockwise.
(FX -4DA and FX
2N
7.2.1 Adjustment of gain
The gain value can be set to an arbitrary digital value.
However, using the maximum 12bit resolution provides the user with a digital range of 0 to 4000.
Voltage input
characteristic(0 to 10V)
At shipment
4000
7.2.2 Adjustment of offset
The offset value can be set to an arbitrary digital value. However, it is advisable to set the analog value
when the digital value is set as following.
Voltage input
characteristic(0 to 10V)
At shipment
40
0
For instance, when a digital range of 0 to 4000 is used with the analog range of 0 to 10V, a digital value of
40 is equal to an analog input of 100mV. (40 × 10V/4000 digital points)
1) The offset and gain adjustments for CH1 and CH2 are accomplished at the same time. When the
offset and gain values of one channel are adjusted, the other channel is automatically adjusted.
2) Repeat the offset and gain adjustment alternately until a stable value is reached.
3) Each channel is common to the analog input circuit. However, check each channel individually for
maximum accuracy.
4) Adjust offset / gain by using subsection 8-3 "Example of programming making average value data"
when a digital value is not steady.
5) Adjust the gain before the offset.
-2AD for current or differing voltage inputs except 0 to 10V DC, it is necessary to
Current input
FX -2AD
2N
VIN
Current
IIN
generator
-2DA can be used instead of the voltage and current generator)
2N
0 10V
Analog value
100mV
Analog value
Voltage input
0 to 1V
5 to 10V
±
: 0.1V, Current input:
+ -
FX
A VIN
+
IIN
COM
Voltage input
characteristic(0 to 5V)
4000
0 5V
Analog value
Voltage input
characteristic(0 to 5V)
80
0 100mV
Analog value
Current input
±
0.16mA)
Volume
*1
-2AD
2N
POWER
OFFSET
GAIN
Current input
characteristic(4 to 20mA)
4000
0 4mA 20mA
Analog value
Current input
characteristic(4 to 20mA)
25
0 4mA 4.1mA
Analog value
0 to 4mA
20mA
A/D
OFFSET
volume
OFFSET
GAIN
AD GAIN
volume