Mitsubishi Electric MELSEC iQ-R User Manual page 68

Setting example of the input signal error detection
The following shows a setting example for detecting an input signal error when an analog input value is greater than 21.6mA
or is smaller than 0.4mA in the channel set as shown below.
Item
Input range
'Input signal error detection auto-clear enable/disable setting' (Un\G302)
'CH1 Input signal error detection setting' (Un\G528)
Assign the following values in the formula for calculating the input signal error detection lower limit setting value and the input
signal error detection upper limit setting value.
• Input signal error detection lower limit value: 0.4mA
• Input signal error detection upper limit value: 21.6mA
• Lower limit value of the range: 4.0mA
• Offset value: 4.0mA
• Gain value: 20.0mA
■Input signal error detection lower limit setting value
Input signal error detection lower limit setting value = ((4.0 - 0.4)  (20.0 - 4.0))  1000 = 225 (22.5%)
Thus, set 'CH1 Input signal error detection lower limit setting value' (Un\G529) to 225 (22.5%).
■Input signal error detection upper limit setting value
Input signal error detection upper limit setting value = ((21.6 - 20.0)  (20.0 - 4.0))  1000 = 100 (10.0%)
Thus, set 'CH1 Input signal error detection upper limit setting value' (Un\G530) to 100 (10.0%).
■Operation
The following graph shows the operation of the input signal error detection.
In
21.6mA
H
V/I
20mA
G
V/I
4mA
O
In
0.4mA
L
(1)
In : Input signal error detection upper limit value
H
V/I : Gain value
G
V/I : Offset value (Lower limit value of the input range)
O
In : Input signal error detection lower limit value
L
(1) Error detection
(2) 1.6mA (10.0% of 16mA)
(3) 16mA (Gain value - Offset value)
(4) 3.6mA (22.5% of 16mA)
1 FUNCTIONS
66
1.12 Input Signal Error Detection Function
Setting value
4 to 20mA
Disable (1)
Upper and lower limit detection (1)
(1)
(2)
(3)
(4)