After repairing the equipment for so many years, seriously, the reason behind the 445 alarm is especially concentrated, basically just those few things, the law is obvious.
1. Encoder cable internal broken wire - this is definitely the number one suspect, no one!
A lot of people check the light look at the wire skin, the outside is intact, think it's okay, in fact, all the trouble in the inside. Especially the kind of installed in the drag chain every day with the machine running back and forth line, bending for three to five years, copper wire fatigue. The appearance of a beautiful line, in fact, has been broken inside the lotus root, contact sometimes good and sometimes bad. Typical symptom is that the machine is moving on the alarm, you reach out and gently shake the line, the alarm immediately changed a pattern - either disappear, or change the other number out. We have encountered more such cases than we can remember.
2. Poor contact with the plug
Sometimes the wire is really not broken, but the connector is not secure. It may be that when you first plugged it in, you didn't dislike it to the end, or the pins may have oxidized a film, or it may have been stained with dirt in an oil mist environment for a long time. This situation is particularly common in the coolant splash, shop oil mist on the machine, the connector pulled out a look, the pins on the oily, the contact resistance becomes large, the signal can be stable only strange.
3. Electromagnetic interference - the workshop's electrical environment is too "busy”
Some factories in the frequency converter, a bunch of big motors, wires and cobwebs like tangled together, encoder signal line and power line pasted tightly, the ground line is also sloppy. At this time the frequency converter is started, interference whooshing into the signal line, the encoder originally rules and regulations to pass the data, was disturbed by a stirring on the jump digital. The system looks at the data popping up, immediately recognized as anomaly.
This ratio is not high, but it does exist. With ten years of old equipment, encoder photoelectric components or circuit aging, the output signal itself with a little jitter. This is generally slow to appear, the beginning of the occasional report, and then more and more often.
5. Water and oil in the connector
A very real reason. Plug sealing is not good, the coolant seeps in along the seam, or oil mist condensation over the years in the inside, like a layer of paste, contact can be good to hell.
