Selection Of Encoder Type - Toshiba E6580772 Instruction Manual

★ Caution in case of using open collector encoder connection
In case using pulse command oscillator and open collector encoder, the rise time of the voltage when the
transistor is OFF tends to be longer than the fall time at the time when the transistor is ON. Therefore, if the
maximum input frequency becomes higher, the pulse duty cannot maintain the 50±10% specification.
Conduct derating on the maximum input frequency so that the pulse duty will be within the following
specification range.
<Derating computation formulae of open collector's maximum input pulse frequency >
0.8／(Maximum input frequency x A) – Voltage rise time ≧ 3 x 10
A : (single phase input: 2) (two-phase input: 4)
Voltage rise time ＝ Encoder exclusive pulse rise time + R x C
Encoder exclusive pulse rise time (s) : Please inquire at the encoder manufacturer.
R (Ω) (Input resistance)
C(F) (Cable static capacity)
<Example>
Encoder : LBJ-005-500 (SUMTAK), 2-phase input
Cable : ROVV-SB-0.2-5P-10m (Furukawa Electric Co., Ltd)
From Formulae①
0.8／(Maximum input frequency x A) – Voltage rise time ≧ 3 x 10
Voltage rise time = (0.35 x 10
[Maximum input frequency] ≦87912 (Pulse/s) [Single phase input]

3.2.3 Selection of encoder type

The encoder type should be selected, following the table below.
Encoder Type
Rated voltage output with emitter/follower
combination.
Complementary High anti-nose characteristics. High-speed response.
Long-distance transmission capability.
Need to pay attention to waveform irregularity.
The collector of the transistor is output directly.
Low anti-noise characteristics. Low-cost.
Open Collector
Need to pay attention to waveform irregularity and
distortion.
Encoder pulse rise time : 0.35 x 10
Static capacity : 120 x 10
–6
) + 1000 x (120 x 10
-6
= 1.55 x 10
≦43956 (Pulse/s) [Two-phase input]
Characteristics
: internal resistance 1000(Ω)＋external resistance value
(In case there is external resistance)
: Please inquire at the cable manufacturer.
-6
(s)
–12
(F/m) x 10 (m)
-12
x 10)
18
E6580772
–6
.....①
–6
Maximum Wiring Length
１００ｍ
１０ｍ