Mitsubishi Electric NZ2EX2B-60AD4 - Page 105

103
CHAPTER 8 FUNCTIONS
8
8.9 Input Signal Error Detection Function
(3) How the input signal error detection function operates
(a) For the main A/D converter module
The digital operation value of the channel in which an error is detected is held at the value just before the error
detection, and CH A/D conversion completed flag (RX10 to RX13) of the corresponding channel turns off.
In addition, once the analog input value returns to a value that is larger than the criteria of disconnection
detection, A/D conversion resumes regardless of the reset of Input signal error detection flag (RWrA) and Input
signal error detection signal (RX1C). After the first update, CH A/D conversion completed flag (RX10 to
RX13) of the corresponding channel turns on again. (The ALM LED of the main module keeps flashing.)
(b) For the extension A/D converter module
The digital operation value of the channel in which an error is detected is held at the value just before the error
detection, and CH A/D conversion completed flag (RX20 to RX23) of the corresponding channel turns off.
In addition, once the analog input value returns to a value that is larger than the criteria of disconnection
detection, A/D conversion resumes regardless of the reset of Input signal error detection flag (RWr1A) and
Input signal error detection signal (RX2C). After the first update, CH A/D conversion completed flag (RX20 to
RX23) of the corresponding channel turns on again. (The ALM LED of the main module keeps flashing.)
The digital operation value is not updated while the input signal error is being detected.
Once the analog input value is out of the disconnection detection condition, updating the digital operation value resumes.
(4) Detection cycle
This function is executed per sampling cycle.
(5) Clearing the input signal error detection
Check that the analog input value returns to a value that is larger than the criteria of disconnection detection and
Error flag (RXA) turns off, and then turn on and off Error clear request flag (RYA).
When the input signal error is cleared, the A/D converter module results in the following state:
• Input signal error detection flag (RWrA, RWr1A) is cleared.
• Input signal error detection signal (RX1C, RX2C) turns off.
• The ALM LED turns off.
• The alarm code stored in Latest warning code (RWr1) is cleared.