Mitsubishi Electric R60AD8-G User Manual page 42

■Simple disconnection detection
This function outputs an alarm when an analog input value is 0.5V or smaller or 2mA or smaller.
By combining this function with the extended mode in the input range setting, simple disconnection detection is enabled.
When an analog input value satisfies either of the following conditions, a disconnection occurs and 'Input signal error
detection flag' (Un\G40) turns on.
Input range
4 to 20mA (extended mode)
1 to 5V (extended mode)
Analog input value
2mA or 0.5V
Error
detection
The settings for 'CH1 Input signal error detection lower limit set value' (Un\G529) and 'CH1 Input signal error detection upper
limit set value' (Un\G530) are ignored.
Notification
When an input signal error is detected, an error is notified as follows.
• Input signal error (1) is stored in the corresponding bit of 'Input signal error detection flag' (Un\G40).
• 'Input signal error detection signal' (XC) turns on.
• The ALM LED flashes.
In addition, an alarm code is stored in 'Latest alarm code' (Un\G2). Alarm codes are stored whenever the analog input
satisfies the condition for the input signal error detection.
For details on the alarm codes, refer to the following.
Page 112 List of Alarm Codes
Operation
On the channel where an error is detected, the last digital output value and digital operation value just before the error was
detected are stored.
When the analog input does not satisfy the condition of the input signal error detection, the A/D conversion resumes
regardless of the reset on Input signal error detection flag (Un\G40) and Input signal error detection signal (XC). (The ALM
LED remains flashing.)
• When an input signal error occurs, the digital output value and digital operation value are not updated.
• The A/D conversion continues on the channel where no Input signal error is detected.
• Whether an input signal error occurred is judged with the value when the first A/D conversion is completed.
Thus, the corresponding bit of 'A/D conversion completed flag' (Un\G42) turns on even when an input signal
error is detected.
Detection cycle
This function works at every sampling cycle.
1 FUNCTIONS
40
1.7 Input Signal Error Detection Function
Disconnection detection value
Analog input value  2mA
Analog input value  0.5V
Time