Questions about RS232 electromagnetic interference-CodePudding

your PC with MFC development, the purpose is to control a servo motor sports institutions and instruments on the servo motor coordination, communication with instrument is RS232 (instrument itself only provides the RS232 port), communication with servo motor is RS485, are all use the same PC (industrial), with a different serial port (motor COM1, COM2) instrument control, but now the situation is: instruments and separate servo motor can be a very good job, once the instrument stand to the machine (in the case of open motor PLC power supply switch), the instrument can't connect, control motor instruction is also unable to send out, there was a problem in both the serial port to send and receive data, for example:
open the motor power supply switch, instrument was unable to connect to turn off the switch, instrument to work properly,
In the case of a power supply switch, separate connection motor COM1, serial data transceiver is normal, can control motor, once planted instruments end COM2, serial port to send out data, unable to control the motor, the instrument can't work
To connect RS232 shield shell, the effect is, but still cannot solve the above situation, so want to ask, what is the cause of the problem, if the electromagnetic interference, electromagnetic anti-interference ability, how to improve the RS232 RS232 line 6-10 meters long,
Please advice, because I had majored in computer and for electrical is really don't know anything, this problem has plagued me more than two months, to write software 1 month already, use serial assistants debugging has no problem, but has been unable to do the actual debugging,

CodePudding user response:

Since the equipment is 485 with 485 interface
Open motor disturbance is serious, may need to be isolated, buy a USB (or 232) turn 485 with isolated conversion head give it a try

CodePudding user response:

simple schematic diagram as shown, also please guide

CodePudding user response:

To find which is interfered with,
May be your instrument be interference, also may be 6 to 8 meters is interference with communication line, can also be COM2 is COM1 interference

CodePudding user response:

reference 1st floor zgl7903 response:

since the equipment is 485 with 485 interface
Open motor disturbance is serious, may need to be isolated, buy a USB (or 232) turn 485 with isolated conversion head try

Equipment is the 485

reference zzz3265 reply: 3/f

to find which is interfered with,
May be your instrument be interference, also may be 6 to 8 meters is interference with communication line, may also be interference COM2 is COM1

Instrument is a very big company production of authority, should not have a problem,
Two separate devices, even meet at the same time, two serial transceiver is no problem,
So, I think the line may be a larger interference factors,

CodePudding user response:

reference 1st floor zgl7903 response:

since the equipment is 485 with 485 interface
Open motor disturbance is serious, may need to be isolated, buy a USB (or 232) turn 485 with isolated conversion head try

Ok, ready to do this, reply again after effect how

CodePudding user response:

1 lower baud rate
2. Single point grounding

CodePudding user response:

This ultimately or hardware problems, find your hardware engineer to solve,,

CodePudding user response:

Why not change a line or in a short point of on-line?

CodePudding user response:

The

refer to the original poster keaiyuzong response:

your PC with MFC development, the purpose is to control a servo motor sports institutions and instruments on the servo motor coordination, communication with instrument is RS232 (instrument itself only provides the RS232 port), communication with servo motor is RS485, are all use the same PC (industrial), with a different serial port (motor COM1, COM2) instrument control, but now the situation is: instruments and separate servo motor can be a very good job, once the instrument stand to the machine (in the case of open motor PLC power supply switch), the instrument can't connect, control motor instruction is also unable to send out, there was a problem in both the serial port to send and receive data, for example:
open the motor power supply switch, instrument was unable to connect to turn off the switch, instrument to work properly,
In the case of a power supply switch, separate connection motor COM1, serial data transceiver is normal, can control motor, once planted instruments end COM2, serial port to send out data, unable to control the motor, the instrument can't work
To connect RS232 shield shell, the effect is, but still cannot solve the above situation, so want to ask, what is the cause of the problem, if the electromagnetic interference, electromagnetic anti-interference ability, how to improve the RS232 RS232 line 6-10 meters long,
Please advice, because I had majored in computer and for electrical is really don't know anything, this problem has plagued me more than two months, to write software 1 month already, use serial assistants debugging has no problem, but has been unable to do the actual debugging,

Must first determine the electromagnetic interference problem? With short line + long term test respectively?

If the electromagnetic interference, must use good quality communication line, conditional and physical shielding layer, a treasure to sell this kind of anti-interference shielded wire

CodePudding user response:

232 turn 485, then the servo

CodePudding user response:

Should not interfere with the perception problem

CodePudding user response:

May not be altogether?
Open the serial debugging assistants, issued instructions, and then use the oscilloscope to see did you send the data of 485 and 232.

CodePudding user response:

6-10 m, line is too long, 485 is recommended for so long

CodePudding user response:

RS232 with shielded wire single point grounding

CodePudding user response:

And instrument 232 connecting line is too long, first try in short term, generally less than 2 m RS232 cable, pay attention to the ground wire RS232, can also add the circular