About power supply and encoder and PLC connection2021

Generally, there are three kinds of power supply for encoder: 5Vdc, 5-13 Vdc or 11-26Vdc. If the encoder you buy uses 11-26Vdc, you can use the 24V power supply of the PLC. Please note that:

1. The current consumption of the encoder is within the power range of the PLC.

2. If the encoder outputs in parallel, it is connected to the I/O point of the PLC. It is necessary to know whether the signal level of the encoder is push-pull (or push-pull) output or open-collector output. For open-collector output, there are N-type and There are two types of P type, which must be the same as the I/O polarity of the PLC. If it is a push-pull output, there is no problem with the connection.

3. If the encoder is a driver output, the signal level is generally 5V. When connecting, be careful not to let the 24V power supply level be serially connected to the 5V signal wiring to damage the signal terminal of the encoder.

Encoder wiring

Rotary encoders can provide high-speed pulse signals, which are often used in CNC machine tools and industrial control. The output frequency and phase number of different types of encoders are different. Some encoders output A, B, C three-phase pulses, some only have two-phase pulses, and some have only one-phase pulses (such as A-phase), with frequencies of 100 Hz, 200 Hz, 1k Hz, 2k Hz, and so on. When the frequency is relatively low, the PLC can respond; when the frequency is high, the PLC cannot respond. At this time, the output signal of the encoder must be connected to the special function module. For example, the FX2N-11C uses the FX2N-11HC high-speed counting module.

Figure 3 is a schematic diagram of the interface between FX2N PLC and OMRON's E6A2-C series rotary encoder.