Regarding communication issues between DCS and 3500
Thread Content
Our factory uses Yokogawa CS3000 DCS. Communication interruptions often occur during the communication between DCS and 3500. There is no other way to solve it, and we have never found out what is causing the problem. After the communication is interrupted, the 3500 program can only be uploaded from the 3500 again. After downloading once, the communication becomes normal. Here I would like to ask if anyone has encountered this situation, what is the cause, and if there is any solution. Please help me. Thank you very much.
Is there any expert who can give me an answer? Thank you.
I am familiar with cs3000, but I don’t understand cs3500.
Why doesn’t this system have a redundant system? :L
I don't think it's a redundancy issue.
I have done communication between BENTLY3500 and CENTUM-CS using the RS232 interface without any problems. But if it is with CS3000, I guess you are using the RS485 interface. I think there are two points that need to be carefully checked.: 1. The communication settings of the BENTLY system and the CS3000 system must be consistent and correct. Please refer to the manual. 2. Check the intermediate communication line to see if there is any interference that will affect the communication quality.
I am currently studying Yokogawa's DCS on my own, but I don't know much about it yet.
I have never encountered your problem, but I have used both systems. You can try the following: 1. After downloading the configuration, the communication is normal, which means there are no errors in the configuration. I would like to ask whether the program re-read from the 3500 after the communication is interrupted is the same as the downloaded one? It may be caused by the loss of 3500 configuration content. 2. It is unlikely that there is a problem with the middle communication line, because the communication is normal after downloading. Is it a problem with the communication interface?
The re-read program and the downloaded program are all original programs. I also suspect that there may be a problem with the intermediate circuit. However, since the compressor has been running, there is no condition to check. It can only be confirmed when it is stopped for maintenance. It is really depressing.
We are connected between TRICON and 3500. Recently, the 3500 has experienced communication interruption and the screen is dead. It may be the same as your situation. Our preliminary judgment here is that the communication card of the 3500 may have a problem. You can replace the spare card and observe and test to see if it is a hardware problem or a line interface or configuration problem!
The 3500 used in our factory communicates with the DCS using RS485 communication. The recent situation is similar to yours. The vibration displacement value displayed by the DCS remains unchanged, but a red alarm appears. It only takes about 1 second to return to normal. Our analysis believes that there is a data packet drop phenomenon in the communication between the 3500 and the DCS. The data is lost and the DCS does not collect it. The next acquisition and scanning cycle returns to normal. This phenomenon is caused by the congestion of communication lines caused by interference introduced into the DCS. It can be used as a reference for your phenomenon.
Why must we use communication? You can use hard wires from 3500 to connect the required signals to the DCS, which is more reliable. First, there will not be too many channels with 3500, and using hard wires will not increase the cost much. ； Second, the parameters of the 3500 band are all key parameters of the unit, such as rotation speed, displacement, vibration, etc., which can be more accurately controlled with hard lines. ； Third, communication problems will really occur, and it is difficult to solve. Once a problem occurs, all parameters will be invisible, and if the operation fails, the machine will stop directly. At that time, the appearance will be as good as the mute, and I can't tell you the pain of eating yellow lotus. :'( :'( :'(
It is recommended that the parameters involved in the chain, such as shaft vibration and displacement, are logically calculated through the relay card 32/33 of the 3500, and then hard-wired to the safety emergency stop system, or the contacts are directly connected to the parking control loop, so that the chain action will be timely and reliable. In addition, if there are few analog points, hard-wiring can be used to control the system. If there are more, it is more reasonable to use communication to control the system. But you must not use communication signals to participate in the chain. I don’t quite understand the author’s recovery after downloading the 3500 program. First of all, how can I dare to download the 3500 program while driving (the 3500 will stop running during the downloading process). If I dare to download the program, then there will be no problem if I check the communication line again. This post was last edited by hxmhn on 2009-3-15 19:47 ]
What you said above is very good. We also use the 3500 relay card output.