Coder and PLC connection method and the encoder selection considerations
As we know, is a kind of photoelectric rotary encoder rotation measurement device, it will be converted into digital signals directly measuring the angular displacement of (
High speed pulse signal)
So, we will be in the application of rotary encoder output pulse signal input to the PLC directly, using the PLC high-speed counter to count the pulse signal, in order to obtain the measured results.
Note: different types of rotary encoder, the output pulse phase number will be different!
Some rotary encoder outputs A, B and Z three-phase pulse, some only A and B phase two phase, the simplest only A phase.
We will output a two-phase pulse in the application of rotary encoder connection with FX series PLC.
So, how to connect?
Usually, the encoder has four lead, two of them are pulse output line, 1 is COM back line, 1 is the power cord.
Rotary encoder and the connection method of PLC selection considerations encoder and rotary encoder of the power supply can be an external power supply, also can directly use PLC DC24V power supply.
'end to the encoder COM end connection,' + 'connected to the power supply end of the encoder.
Encoder COM end connected to the PLC input COM port, A, B two phase pulse output line directly connected with the input end of the PLC.
Note: in the process of connecting link need to pay attention to the PLC input response time;
Some rotary encoder and a shielding line, shielding wire to be used when the grounding.
Encoder if is parallel output, can be directly connected to the PLC or PC I/O, input/output contact their signal mathematical format should be a gray code.
How many people are there in the encoder would take PLC how much contact, if it is 24 v push-pull output, the effect of high level 1, and low level of 0;
If the NPN is open collector output, the connection of contact must also be NPN, its high effective, low level of 1.
As a result, the rotary encoder selection need to pay special attention to the following three aspects: one, the mechanical installation size, including positioning check mouth, trunnion, mounting holes;
Cable wire way;
Installation space volume;
Work environment protection grade whether meet the requirements.
Second, the resolution, namely each lap of the output pulse encoder work number, use the precision whether meet the design requirements.
The output of the encoder frequency does not exceed PLC allowed range.
Third, the electrical interface, encoder output way has a push-pull output (common
F type HTL format)
The output voltage, (
, open collector (
C, C for common NPN output, C2 for PNP tube output)
Long-term drive output.
Match the output methods with PLC interface circuit.
Above tells the story of rotary encoder connection details of the process of installation, you can pay attention in the work, and on the selection of the rotary encoder also pay attention to the above three elements, so you can better the application of the encoder.
If you have any don't understand the problem, can at any time to consulting electronics, Shanghai electronic 25 years specializing in the production of rotary encoder, trustworthy!