8-7
Over Range/Under Range Detection
8-7-1
Function Applications and Overview
This function detects when the analog input signal exceeds the range for which conversion is possible.
8-7-2
Details on the Function
The operations of the over range/under range detection are described below.
• If the input signal exceeds the upper limit of the input conversion range, the converted value is fixed
at the upper limit. If this state continues for 100 ms, the Ch£ Over Range bit in the Ch£ Status of
I/O data turns ON and a Unit Over Range for Ch£ event occurs. (Refer to (a) in the figure below.)
• If the input signal falls below the lower limit of the input conversion range, the converted value is
fixed at the lower limit. If this state continues for 100 ms, the Ch£ Under Range bit in the Ch£
Status of I/O data turns ON and a Unit Under Range for Ch£ event occurs. (Refer to (b) in the fig-
ure below.)
• When the input signal returns to the input conversion range, the fixing is canceled and the values
become the converted values.
When the cause of the error is removed and the error is reset, the Ch£ Over Range and Ch£ Un-
der Range bits of the Ch£ Status of I/O data turn OFF. (Refer to (c) in the figure below.)
• Refer to 7-1 Specifications of I/O Data on page 7 - 2 for details on I/O data. Refer to 9-3-3 Event
Codes and Corrections for Errors on page 9 - 6 for details on events.
1
100 ms
100 ms
0
1
0
Upper limit of input
conversion range
Analog input signal
Converted
value
Error is reset
Lower limit of input
conversion range
Ch
*
Over Range bit
Ch
*
Under Range bit
(a)
(b)
(c)
8 Functions
8 - 31
NX-series Analog I/O Units User’s Manual for High-speed Analog Input Units (W592)
8-7 Over Range/Under Range Detection
8
8-7-1 Function Applications and Overview
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