3BHB003154R0101 3BHL000389P0104 | ABB | PLC input/output terminals

Description

3BHB003154R0101 3BHL000389P0104 | ABB | PLC input/output terminals

When the input signal source is an inductive component and the output driven load is an inductive component, for 3BHB003154R0101 circuits, freewheeling diodes should be connected in parallel at both ends. For AC circuits, impedance capacitance absorption circuits should be connected in parallel at both ends. Its function is to prevent high induced electromotive force or surge current from impacting the input/output terminals and internal power supply of the 3BHB003154R0101 when the inductive input or output circuit is disconnected. If the driving components of the PLC are mainly solenoid valves and AC contactor coils, a zero crossing solid-state relay with photoelectric isolation should be added between the PLC output terminal and the driving components.
② Error prevention of input/output signals
When the output component is a bidirectional thyristor or transistor and the external load is small, because such output components have a large leakage current when turned off, making it difficult for the input circuit and external load circuit to turn off, resulting in input/output signal errors. Therefore, a bypass resistor should be connected in parallel at these input/output terminals to reduce the input current of the 3BHL000389P0104  and the current on the external load.
③ 3BHL000389P0104  Leakage current
When using DC two wire sensors such as proximity switches and photoelectric switches for input signals, if the leakage current is large, the resulting misoperation should be considered to prevent the PLC input signal from being turned off. Generally, a bypass resistor is connected to the input terminal of the PLC to reduce input impedance. When using bidirectional thyristors for output, in order to avoid output component failure caused by leakage current and other reasons, a side resistor can also be connected in parallel at the output end.