Level Pro ITC 450, User Manual

Page: 24 / 59

If tA ,tB ,tC or tD (when input signal stay in zone A or zone B ) are lower than parameters “t on” or “toFF”, the
relay will not change his state (see points A and C, Figure 6.7 a, d, e).
The state of relay output while the input value exceeds the border values (points A, B, C, D) is described by
parameter “modE” . The relay can be turned on ( “modE” = ”on” ), or turned off ( “modE” = ”oFF” ) when input
signal value is contained in zone A (Figure 6.7 a).
The parameter “AL” allow user to set the relay output behaviour in critical situations (e.g. Input values
exceeds permissible measurement range). User can select that the relays will be turned on, turned off,or not
changed in critical situations.
All parameters connected with relay outputs are described in paragraph
”rEL1” menu .
6.3.2. Two thresholds mode
E
OFF
“SEt P” or “SEt P2”
parameter
“HYSt” parameter
A
B
C
A C
B
ON
“t oFF” parameter
“t on” parameter
B
OFF
E
ON
“t on” parameter
“t oFF” parameter
C
OFF
C
ON
E
“t on” parameter
“t oFF” parameter
B E
“HYSt” parameter
relay state
( modE = in
t on = 0
t oFF = 0)
relay state
( modE = out
t on = 0
t oFF = 0)
relay state
( modE = in
t on = 0
t oFF = 0)
relay state
( modE = out
t on = 0
t oFF = 0)
Figure 6.8. Principle of LED/relay output operation for two thresholds mode
Description:
A, B, C, D
B
ON
,B
OFF
,C
ON ,
C
OFF ,
E
ON
, E
OFF
t
A
, t
B
, t
C
, t
D
, t
E
- points where measured signal exceeds border values (expected value ± allowed deviation)
- relays state changes moments: (for “t on” > 0, “t oFF” > 0)
- time periods while input signal is in zone A or zone B
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ITC 450/470
User manual