We know that the rotary encoder is a photoelectric rotary measuring device, the measured angular displacement will be directly converted into a digital signal (high-speed pulse signal). So, we will be entered directly in the application of the rotary encoder outputs a pulse signal to the PLC, use PLC high-speed counter to its pulse signals are counted to obtain measurement results.
　　Note: the number of phases of different types of rotary encoder, the output pulse is will vary and some rotary encoder output A, B, Z phase pulse, and some only A, B two-phase, the most! a simple phase only.
　　Applications we will connect the two-phase pulse output of the rotary encoder with the FX series PLC.
　　So, how to connect it?
      　　Typically, the encoder has four leads, two of which are pulse output line, a COM is the end line, a power cord.
Connections rotary encoder and PLC and rotary encoder Selection Considerations   　　Encoder power source can be an external power supply, it can also be used directly from the PLC DC24V power supply. Power "-" terminal to be connected with COM encoder "+" power supply terminal and encoder connections. COM of the encoder and the PLC COM input terminal is connected, A, B two-phase pulse output is connected directly to the input of the PLC.
　　The connection process Note: Note that the response time of PLC input connection; some rotary encoder there is a shielded cable, the use of shielded wire to the ground.
　　If the parallel encoder output can be directly connected to PLC or PC input output contact I / O, its mathematical signal format should be a Gray code. Encoder How many will take up the PLC how many contacts, if it is a 24 volt push-pull output, active high 1, a low level of 0; if it is an open-collector NPN output, the connection contacts must It is NPN type, the active high-low 1.
　　Thus, the rotary encoder selection requires special attention to the following three aspects:
　　A mechanical dimensions, including positioning spigot, shaft, mounting holes; cable and outlet; installation space volume; environment protection level meets the requirements.
     　　Second, the resolution, namely, when the number of encoder output pulses per turn, whether to meet the design requirements for the use of precision. The encoder output frequency should not exceed the allowable range of the PLC.
     　　Third, the electrical interface, the encoder output common push-pull output (F-type HTL format), the voltage output (E), open collector (C, common C for the NPN-tube output, C2 PNP type tube output), long drive output. And its output should match the PLC interface circuitry.
　　As tells the rotary encoder connected to the installation details of the process, we can take note at work, and on the selection of the rotary encoder also note under the above three elements, so that it can better use the encoder. If any understand the problems, you can always to consult or Granville Electronics, Guangdong Granville electronic manufacturing rotary encoder 25 years, trusted!