Hitachi L700 Series, Instruction Manual, Page: 136 / 263

Chapter 4 Explanation of Functions
4 - 74
4.2.77 Window comparators (WCO/WCOI/WCO2) (detection of terminal disconnection:
ODc/OIDc/O2Dc)
- The window comparator function outputs
signals when the values of analog inputs O,
OI, and O2 are 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, and O2.
- You can fix the analog input data to be applied to an arbitrary value when WCO, WCOI, or WCO2 is
output. For this purpose, specify a desired value as the operation level at O/OI/O2 disconnection
(b070/b071/b072). When "no" is specified, the analog input data is reflected as input.
- Output values of ODc, OIDc, and O2Dc are the same as those of WCO, WCOI, and WCO2, respectively.
Item
Function
code
Range of data Description
Terminal [11] to terminal
[15] functions
C021-C025
C026
27
ODc: Detection of analog input O
disconnection
28
OIDc: Detection of analog input OI
disconnection
29
O2Dc: Detection of analog input O2
disconnection
Alarm relay terminal
function
54 WCO: Window comparator O
55 WCOI: Window comparator OI
56 WCO2: Window comparator O2
Maximum-limit level of
window comparators
O/OI/O2
b060 (O ) "Minimum-limit level + hysteresis width*2
(minimum of 0)" to 100. (%)
Setting of maximum-limit level
b063 (OI)
b066 (O2)
"Minimum-limit level + hysteresis width*2
(minimum of -100)" to 100. (%)
Minimum-limit level of
window comparators
O/OI/O2
b061 (O ) 0 to "maximum-limit level - hysteresis
width*2 (maximum of 100)" (%)
Setting of minimum-limit level
b064 (OI)
b067 (O2)
-100 to "maximum-limit level - hysteresis
width*2 (maximum of 100)" (%)
Hysteresis width of
window comparators
O/OI/O2 b062 (O )
0 to "(maximum-limit level - minimum-limit
level)/2 (maximum of 10)" (%)
Setting of hysteresis width for
maximum-limit and minimum-limit
levels
b065 (OI)
b068 (O2)
Operation level at
O/OI/O2 disconnection
b070 (O )
0 to 100 (%) or "no" (ignore)
Setting of the analog input value to be
applied when WCO, WCOI, or WCO2
(ODc, OIDc, or O2Dc) is output.
b071 (OI)
b072 (O2) -100 to 100 (%) or "no" (ignore)
C021 to C025: Terminal [11] to terminal [15] functions
C026: Alarm relay terminal function
b060/b063/b066: Maximum-limit level of window comparators O/OI/O2
b061/b064/b067: Minimum-limit level of window comparators O/OI/O2
Related code
Maximum-limit level of window
comparator (b061/b064/b067)
Minimum-limit level of window
comparator (b060/b063/b066)
WCO/WCOI/WCO2
ODc/OIDc/O2Dc
Max(100%)
Min(O/OI:0%)
(O2 :-100%)
O, OI, or O2
Applied analog data
Applied analog data
Analog operation level at
disconnection (b070/b071/b072)
Hysteresis width
(b062,b065,b068)