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CHAPTER 8 FUNCTIONS
8
8.8 Input Signal Error Detection Extension Function
(a) Disconnection detection
By combining this detection method with the input range extended mode function, simple disconnection
detection can be performed. When either of following conditions is satisfied, Input signal error detection flag
(Un\G49) turns on and a disconnection occurs.
The setting for CH Input signal error detection setting value (Un\G142 to Un\G145) is ignored.
(2) Notification of input signal error
If the analog input value satisfies the detection condition of the set detection method, the error is notified by Input
signal error detection flag (Un\G49), Input signal error detection signal (XC), and the flashing ALM LED. In
addition, alarm code 11 gets stored in Latest error code (Un\G19). The value of the alarm code to be stored
varies depending on the condition (upper limit, lower limit, or disconnection detection) under which an error of the
analog input value is detected.
The following shows the alarm code to be stored.
For details on alarm codes, refer to the following.
• Alarm code list (
Page 163, Section 11.5)
(3) Operation of the input signal error detection extension function
The operation is the same as that of the input signal error detection function.
For details, refer to the following.
• Input signal error detection function (
Page 69, Section 8.7)
(4) Detection cycle
This function is executed per sampling cycle.
Input range Disconnection detection condition
4 to 20mA (Extended mode) Input analog value ≤ 2mA
1 to 5V (Extended mode) Input analog value ≤ 0.5V
Analog
input value
Tim
Error
detection
2mA or 0.5V
11
The last digit indicates the channel where an input signal error has occurred.
The tenth digit indicates the detection condition by one of the following values:
1: Lower limit detection
2: Upper limit detection
3: Disconnection detection
Fixed
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