Encoder application problem analysis and improvement measures

(a) encoder problem analysis in the application

Photoelectric encoder detection device of transmitting and receiving device is installed at the scene of the production, has exposed many defects in the use, the internal factors and external

Factors, mainly manifested in the following aspects: 1. Launch device or accept device caused by mechanical vibration of displacement or offset, cause

Receiver can not receive light signals, and does not produce electrical signals. For example; Photoelectric encoder is used in the speed control system of steel rolling, for

Photoelectric encoder is bolted directly on the shell of the motor, photoelectric encoder shaft through a hard spring leaf and motor shaft

Pick up, because the motor load is impact load, when the mill through the steel will cause the vibration of the motor shaft and the shell. The mensuration; When a steel

The rate of 2.6 mm/s for vibration of photoelectric encoder and the vibration velocity can damage the internal function of photoelectric encoder. Create a false pulse, so as to guide

To control the system unstable or misoperation, leading to the accident.

2. Because of the photoelectric encoder testing device is installed at the scene of the production, the production site environmental factors lead to photoelectric detection device can't work reliable. Such as Ann

With high temperature and high humidity, leading to the inside of the photoelectric detection device electronic component characteristics change or damage. For example, in continuous caster dummy tracking

System, the position of the photoelectric encoder testing device installed near the slab, caused by environment temperature high photoelectric detection device error signal or damage, and

Production or personal accident.

3. The scene of the production of various interference sources, the interference detection device and photoelectric encoder in photoelectric detection device the distortion of output waveform distortion

Maloperation accident or trigger production, make the system. For example; Photoelectric encoder detection device is installed on production equipment ontology, the signal via cable transmission to control system

Series of distance in 20 m to 100 m, although transmission cables are generally choose multi-fiber shielded cable, but as a result of cable wire resistance and capacitance between lines

Coupled with the influence of together with other cable laying, vulnerable to the influence of all kinds of electromagnetic interference, so cause waveform distortion, so that the reverse

Feed to the speed control system of the deviation of the signal and the actual value and to lower the system precision.

(2) improving measures

1. Change the way the installation of photoelectric encoder. Photoelectric encoder is not installed on the motor shell, but on the basis of the motor to make a solid

Support to independent installation of photoelectric encoder, photoelectric encoder shaft and motor shaft center must be in the same level height, two axis adopt soft rubber

Or nylon hose connected, in order to reduce the impact load on the motor mechanical shock of photoelectric encoder. Adopting this way after the vibration test, the

Vibration velocity dropped to 1.2 mm/s.

2. Choose the detector output signal transmission medium photoelectric encoder, using twisted-pair shielded cable replace ordinary shielded cable. Twisted-pair shielded cable

Two important technical features, one is the electromagnetic interference on the cable has strong protection ability, because the electromagnetic fields in the online space

Interference current can offset each other. Another technical characteristics of twisted-pair shielded cable is mutual ground after two line spacing is very small, two lines line from the interference

From the basic equal, two lines of shielding network distributed capacitance is basically the same, the common-mode interference suppression effect is more obvious.

3. The use of PLC software to monitor or interference. Send dummy in continuous casting production process requires the photoelectric detection device to produce a timing of electrical signals, and at the same time

The whole process, the signal and corresponding to different stages.