Operating Instructions T411 / T412
JAQUET AG
Revision: 003
22/27
9.2.2 Signal failure
In the event of a sudden loss of a good signal, no positive edge arrives to complete the measurement
or start a new one. Once the minimum measurement time (Fixtime) has lapsed, the unit waits for twice the last
measurement period, following which half the last measured speed is assumed.
If the signal remains missing then the measurement approaches zero following an e-function.
9.3 Functions
9.3.1 Limits and Window Function
Since the upper and lower sets points are freely selectable a large hysteresis may be set. If that is not
necessary we recommend setting a 10% hysteresis.
The Window function allows an Exclusive OR combination of Limits 1 and 2, whereby the status of both limits
is first determined (including any inversion) and a subsequent ExOR comparison executed.
As soon as Relay assignment is <Window> the relay behaves as follows:
•
With identical limit modes (both Normal or both Inverse) the relay is activated when the measured value
lies between the Limit 1 and 2 settings.
•
If different modes are set (one Normal and the other Inverse) the relay is deactivated when the measured
value is between Limits 1 and 2.
9.3.2 Parameter set A and B
T400’s have 2 parameter sets available that define the relay assignment. Parameter set A would normally be
used. If another parameter set is needed, e.g. for test purposes, the binary input may be used to change to
parameter set B. The transfer from parameter set B to parameter set A may be delayed in the range 0 to 2000
seconds. Transferring from A to B is however immediate and not affected by this setting.
To be able to select parameter sets using the binary input, Relay control - Selection of Actuator must be
appropriately set, see 8.5.5.
Binary input condition
Selected Parameter set
High (5V)
„normal“
A
Low (0V)
„connected to 0V“
B
9.3.3 Relay hold function
A latch function may be assigned to the relay. By selecting <Relay is hold if control is active> the relay is
activated once the assigned limit is active and remains held even if the input frequency would no longer cause
a trip. By selecting <Relay is hold if control is inactive>, the deactivated state of the relay is held. The latched
status may be reset by cycling power or via the binary input, whereby the binary input must be activated as per
the configuration (0V or 5V) for between 0.1 and 0.3 seconds.
