Mitsubishi Electric Melsec iQ-R Series User Manual page 44

■Simple disconnection detection
An alarm is output when an analog input value is 2mA or lower.
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, it is regarded as a disconnection and 'Input signal error
detection flag' (Un\G40) turns on.
Input range
4 to 20mA (extended mode)
I
(1)
Error detection
I: Analog input value
t: Time
(1) 2mA
The setting of 'CH1 Input signal error detection setting value' (Un\G529) is 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 82 List of Alarm Codes
Operation
On the channel where an error is detected, the digital output value and digital operation value just before the detection of the
error are stored.
When an analog input value falls within the set range, the A/D conversion is restarted regardless of whether 'Input signal error
detection flag' (Un\G40) and 'Input signal error detection signal' (XC) are reset or not. (The ALM LED remains flashing.)
• The values in 'CH1 Digital output value' (Un\G400) and 'CH1 Digital operation value' (Un\G402) are not
updated during the occurrence of an input signal error.
• The A/D conversion continues on the channel where no input signal error is detected.
• Whether an input signal error has occurred or not is judged with the value of when the 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
42
1.9 Input Signal Error Detection Function
t
Disconnection detection value
Analog input value  2mA