Dynalco SWTD-1000 Speed Switch/Transmitter - Manual (Page 20)

Operating Instructions SWTD-1000 DYNALCO
18 //
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 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 Limts 1 and 2.
9.3.2 Parameter set A and B
The SWTD-1000 has 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 0.
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 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 , the deactivared 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.
9.3.4 Push-Button
The front panel push button internally connects the binary input to 0VS thus generating a logic 0.