Hitachi NES1-002LB, Quick Reference Manual

Page: 152 / 295

Chapter 7 Explanation of Functions
7 - 75
7.8.21 Window comparators (WC) (detection of terminal disconnection:Dc)
- The window comparator function outputs signals when the values of analog inputs O/OI is within the
maximum and minimum limits specified for the window comparator. You can monitor analog inputs with
reference to arbitrary levels (to find input terminal disconnection and other errors).
- You can specify a hysteresis width for the maximum-limit and minimum-limit levels of the window
comparator.
- You can specify limit levels and a hysteresis width individually for analog inputs O/OI.
- You can fix the analog input data to be applied to an arbitrary value when WC is output. For this purpose,
specify a desired value as the operation level at O/OI disconnection (b070). When "no" is specified, the
analog input data is reflected as input.
- Output values of Dc is the same as those of WC respectively.
Item
Function
code
Range of data Description
Terminal [11] functions
C021
C026
27
Dc: Detection of analog input
disconnection
Alarm relay terminal
function
54 WC: Window comparator
Maximum-limit level of
window comparators O/OI
b060
"Minimum-limit level + hysteresis width*2
(minimum of 0)" to 100. (%)
Setting of maximum-limit level
Minimum-limit level of
window comparators O/OI
b061
0 to "maximum-limit level - hysteresis
width*2 (maximum of 100)" (%)
Setting of minimum-limit level
Hysteresis width of window
comparators O/OI
b062
0 to "(maximum-limit level - minimum-limit
level)/2 (maximum of 10)" (%) Setting of hysteresis width for
maximum-limit and minimum-limit levels
Operation level at O/OI
disconnection
b070 0 to 100 (%) or "no" (ignore)
Setting of the analog input value to be
applied when WC (Dc) is output.
Maximum-limit level of window
comparator (b061)
Minimum-limit level of window
comparator (b060)
WC output
Dc output
Max(100%)
Min(0%)
O/OI input
Applied analog data
Analog input data
Analog operation level at
disconnection (b070)
Hysteresis width
(b062)