What signal output does the encoder of absolute value signal have (1, 2)？

What signal output does the encoder of absolute value signal have (1, 2)

I have introduced many times before that there are two types of cable displacement sensor output, digital signal output and analog signal output, and digital signal output is also divided into incremental pulse signal output and absolute value signal output. Today, I will introduce the system. Which signals are also divided into absolute value signals.

If you want to know what signal output the absolute value signal encoder has, you must first know what are the output categories. The absolute value encoder signal output includes parallel output, serial output, bus type output, and transmission-body type output.

1. Parallel output:

The output of the absolute encoder is multi-digit digital (Gray code or pure binary code), and the parallel output is connected.

There are multiple high and low level outputs on the port, with 1 or 0 representing the number. For absolute encoders with low digits, the number is generally output directly in this form, which can directly enter the IO interface of the PLC or the host computer, and the output is instant. Simple connection. However, parallel output has the following problems:

1. It must be a Gray code, because if it is a pure binary code, there may be multiple bit changes when the data is refreshed, and the reading will cause a code error in a short time.

2. All interfaces must be connected well, because if there is a bad connection point, the potential of this point is always 0,

Can't judge because of wrong code.

3. The transmission distance can not be far, usually within two meters. For complex environments, isolation is best.

4. For a large number of digits, a large number of core cables are required, and a good connection must be ensured, which brings engineering difficulties.

Similarly, for the encoder, there must be many node outputs at the same time, which increases the failure rate of the encoder.

2. Serial SSI output:

Serial output is through an appointment, there is a sequential data output in time, this kind of agreement is called the communication protocol,

The physical forms of its connection are RS232, RS42 (TL), RS485, etc.

Since the good manufacturers of absolute encoders are all in Germany, most of the serial output is matched with Siemens in Germany, such as SSI synchronous serial output.

SSI interface (RS422 mode), connected by two data lines and two clock lines, the receiving device sends interrupted clock pulses to the encoder, and the absolute position value is synchronously output to the receiving device by the encoder and the clock pulse. The clock signal sent by the receiving device triggers the encoder to output a serial signal synchronized with the clock signal from the high bit (MSB).

The serial output connection line is few, the transmission distance is long, the protection and reliability of the encoder are greatly improved. Generally, high-bit absolute encoders use serial output.

I think the output signal of the absolute encoder is more complicated, so the length is longer. This time I will mainly introduce the first two, and I will introduce the latter two next time, so stay tuned.