
B–65162E/03
10. INTERFACE SIGNALS
403
D SDTA = 1 occurs when the frequency is lower than the one which is
set by parameter.
D This signal is used to detect that the output frequency has become
lower than a certain frequency set such as clutch selectable speed or
gear selectable speed.
D The frequency detecting level can be set by parameter.
D For this signal, SDTA = 1 occurs when the absolute value of the output
frequency is reduced to be lower than the preset detection level,
irrespective of rotation commands (SFRA, SRVA).
0
SDTA
1
Frequency detection level
1
0min
–1
Output frequency
Fig.10.4.11 (a) Speed Detection Signal
The gear shift in the CNC machine tool is one of the sequence controls.
The electric circuit signal in the sequence is used to move the spindle gear,
which is an important component of the machine. It is then necessary to
check that the spindle motor speed is in low speed to switch the gear
safely.
The following is an example of sequence at gear shift, when the frequency
detection signal (gear selectable signal) was used. This example can be
referred to when designing the magnetics sequencer.
D An example of gear shift sequence using frequency detection
signal
Frequency detection signal=1
(or frequency stopped signal=1)
(Sequence)
(Check signal)
Low speed revolution com-
mand of the spindle motor
Speed check
Shifter moves
End of gear shift
Gear shift command
10.4.11
Frequency Detecting
Signal (SDTA)
Reference
D Sequence of the gear
shift