Electrical Design
‑80‑
When they are used as DI terminals, their wiring mode is consistent with that of DI1 to
DI4. When they are used as DO terminals, the DO common terminal is COM and only
the sink wiring mode is supported, as shown in the following figure. In this case, it is
recommended that the DI common terminal OP be connected to the 24V terminal. If
the OP terminal is connected to the COM terminal, the customer's device may receive
input signals before signals are output through the DIO terminal.
Figure 3‑17 Wiring of DIO terminals used as DO terminals
Wiring of Relay Output Terminals
The inductive load (relay, contactor, and motor) causes voltage spike after the current
is removed. A voltage dependent resistor (VDR) must be used for protection at the
relay contact and absorption circuits such as VDRs, RC absorption circuits and diodes
must be installed on inductive loads to ensure minimum interference during cutoff.
When a contactor and an intermediate relay are connected to 220 VAC, a VDR with a
withstand voltage higher than 275 VAC must be paralleled at both ends of the drive
coil of the contactor and intermediate relay. When a contactor and an intermediate
relay are connected to 24 VDC, a freewheel diode must be inversely paralleled at both
ends of the drive coil of the contactor and intermediate relay, that is, the cathode and
anode of the freewheel diode are connected to the 24 V side and non‑24 V side of the
drive coil respectively.
To Next Page
Loading...
