
B–63503EN/02
7. SERVO INTERFACE
86
Requirements for the signals at the input pins of input connectors JF21
to JF24
TD y 0.15 µsec
The signals for these connectors are differential input signals with A and
B phases. An important factor is time TD from point A, when the
potential difference between PCA and *PCA exceeds 0.5V, to point B,
when the potential difference between PCB and *PCB becomes lower
than 0.5V. The minimum value of TD is 0.15 µs. The period and pulse
width of the signals must be long enough to satisfy the above
requirements.
PCA
*PCA
110Ω
560Ω
5V
The same circuit is used
for B–phase signals
(PCB and *PCB) and
one–rotation signals
(PCZ and *PCZ).
A–phase
signal
TEXAS INSTRUMENTS, INC.: SN75115
If the separate pulse coder rotates in the opposite direction to that of the
servo motor, reconnect the interface cable of the separate pulse coder as
described below.
(1)Exchange signal PCA with signal PCB.
(2)Exchange signal *PCA with signal *PCB.
Time requirements
Receiver circuit
Relationship between
the direction of rotation
of the servo motor and
that of the separate
pulse coder