The following describes the hardware / software conditions: RS232 serial port with no laptop, Omron CPM2AH-60CDR type PLC, Cx-Programmer V5.0 programming software.
1. Cx-Programmer V5.0 and the PLC communications instability:
The connection of computer and PLC: the computer USB port (RS232 serial port of the computer does not have) ??? ???? [USB RS232 Cable USB plug transfer ??? ???? USB transfer cable RS232 (computer installed drivers, and the default port has been set to COM4 COM1) middle ??? ???? USB transfer cable RS232 RS232 male] ??? ???? [[computer and PLC connection cable RS232 Female ??? ???? PC and PLC connection cables in the middle part of the ??? ???? computer and PLC connection cable RS232 public head]] ??? ???? PLC s RS232 female.
In parentheses above the single RS232 USB transfer cable, double the brackets for the computer and the PLC connection cable. Computer and PLC connection cable wiring is as follows: (1). Male (to connect PLC) of the 2,3,9 and female respectively, the 2,3,5 (for connecting a computer or USB-RS232 cable) short Then, this is the official connection method Omron; (2). male and female head of 2-2,3 -3,5-5 were shorted, it is conventional RS232 cable connection method. Was proven: the above two kinds of computer and PLC connection cable can be used. The first one kind of cable communications stable and reliable. For the first two kinds of cables, as between the computer and PLC applications Cheng Xu Tong Guo VC ineffective to communicate, easy to frame dropping (Yong serial debugging aides see), only when the computer and the PLC share Dian Yuan (Gong De) when Mei You found the problem. So, as far as possible the first one kind of connection cables.
Time computer and PLC to the normal communication, but it s not time - display "Modem has been selected, to continue to code?" Failure (in fact, "code" should be "you"), in the event of the failure information, we will be the following fault information:
When the communication is not the time, I had clone before using the normal operating system, reinstall the Cx-Programmer V5.0 programming software and other methods, but also the normal communication, but communication is not possible once the break went after. On several occasions also found that some programs can and PLC communications, while some programs are not! Therefore, I will communicate the PLC program can back up, and then delete all program instructions, the final goal of the program will copy over all the instructions (copy can be automatically copied when the notes), so the computer can actually communicate with normal and PLC a! But - and maybe next time this procedure had not properly communicate! Depressed ... ...
According to CommunicationError message "Modem has been selected to continue code?", I found the solution: Right-click on the desktop "My Computer" and then click "Properties" - "Hardware" - "Device Manager" and then double-click the "modem", then right-click to start the modem type, click the "disabled" on it.
In addition, the correct connection method is as follows: the computer did not boot or (and) PLC no power (or electric plug communication port may cause damage to communications port (although this is not likely, but you better not take a chance)) the situation Next connect the USB transfer RS232 cable, computer and PLC connection cable, and then through the Cx-Programmer connected to the computer and the PLC.
Note: USB port not be lightly can inserted, the key is to ensure that the Device Manager in the RS232 port as COM1. The author s computer when the situation: the first has the default port RS232 port from COM4 to COM1 port, but the USB port is inserted below the COM4 port corresponding to RS232 (COM1, COM3 is in use), can not connect the computer and the PLC; inserted above the corresponding USB port RS232 for COM1 port (COM2, COM4 is being used), you can connect the computer and PLC.
2. Cx-Programmer V5.0 and the PLC communications interference:
If Cx-Programmer online, PC and PLC is connected, in a communication state, when each device shutdown (almost 20 AC contactor while disconnected) Cx-Programmer will be a communication error, computer and PLC connection is lost. And when each boot (nearly 20 contactor at the same time pull) communication errors but will not be the case.
Solution: Reconnect the PLC. If you are a perfectionist, you can add each contactor coil, a RC RC module (about 60 blocks each RC about the ocean), communication errors may not appear the situation (although I have not tried yo .. .).
3. computer and PLC connection cable test:
The thought of computer and PLC connection cable (the first one kind of conventional connection cable) for the 2-2, 3-3 shorted shorted shorted ,5-5, so consider the direct use of USB ??? ???? RS232 cable to connect the computer and PLC up, if so, if you can not save a connection on the cable yet? Here is the direct use of USB ??? ???? RS232 cable to connect the computer and PLC Test Results:
1st time to communicate the following error: "The selected port is occupied by another application"; No. 2 to communicate the following error:
Why are these two computers connected by cable to connect no problem with the PLC, while the direct use of USB-RS232 cable to connect with the PLC is not? The following is the analysis process:
The first one kind of possibility: impedance reasons. Although the two connection cables for the direct connection, there exists resistance, this resistance can be more than the normal connection. But the reason seems to be far-fetched, even the author himself could not believe.
2 possible: the USB-RS232 of male and female PLC, poor contact, and add a cable able to connect properly - USB switch to connect RS232 of male and female line of good contact, cable public PLC of female head and good contact. The speculation comes from the author encountered a computer failure: a computer mouse can not use the other for a normal mouse, the mouse for the fault to the other computer was able to work properly. Last suspect mouse connector poor contact with the motherboard socket, plug the mouse will break open and then coated with solder, the results using normal! But for the male USB-RS232 female poor contact with the PLC, the speculation, I think is unlikely - because he can not explain "the selected port is occupied by another application," the fault.
Finally thought of another possible: USB transfer RS232 PLC to connect directly to the equivalent of USB-RS232 serial port and the PLC s serial port 1-1,2-2,3-3,4-4,5-5,6-6, 7-7,8-8,9-9 correspond to connect through cable only 2-2,3-3,5-5 three pairs of terminals connected, indicating that 1 -1,4-4,7-7,8-8,9-9 at least one pair is not connected, otherwise there will be problems, but it also can damage both PLC and computer communications port. I think that is the reason.