TECO A510s - Control Circuit Wiring; Photo-Coupler Connected to an External Relay

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3.17 Control Circuit Wiring
(1) Separate the wiring for control circuit terminals from main circuit wiring for terminals
(R/L1,
S/L2, T/L3, U/T1, V/T2, W/T3)
.
(2) Separate the wiring for control circuit terminals R1A-R1B-R1C (or R2A, R2C) (Relay outputs)
from wiring for terminals
 - 
, A01, A02, GND, DO1, DO2, DOG, +10V, (-10V), AI1, AI2 and
GND wiring.
(3) Use shielded twisted-pair cables (#24 - #14 AWG / 0.5 -2 mm
2
) shown in Fig. 3.17.1 for control
circuits to minimize noise problems. The maximum wiring distance should not exceed 50m (165
ft).
Fig. 3.17.1 Shielded Twisted-Pair
(4) When the digital multi-function output terminals (DO1, DO2) are connected to an external relay,
a freewheeling diode should be connected across the relay coil to prevent an inductive voltage
spike from damaging the output circuitry as shown in Fig. 3.17.2 below.
+ 48V max.
A510S
DO1, DO2
Free-wheeling diode
(100V, > 100mA)
50 mA max.
Relay Coil
Fig. 3.17.2 Photo-Coupler Connected to an External Relay