sandeep424

Thank You very much for your reply. The ScadaPack LP PLC to which i have to connect follows Modbus - RTU protocol for serial communication. It uses Telepace Ladder Logic Editor to configure the ports and communications, and also handles the program to talk with it slave PLC's with the help of ladder logic program written for slave devices which follows poll type of communication i.e. whenever the data stored in the registers of Master PLCs changes, the Master station acts according to the changes and polls the slave PLC's. But now, i am confused with (1) what changes should i do in the ladder logic program so that it communicates with my FPGA device (2) the Telepace software configuration settings should be changed to detect my FPGA and send it data. The default configuration of the serial port is the one which i require, so is that when i connect my FPGA device does the PLC automotically detect my device or should I configure the serial port again to the required parameters. (3) what are the ASCII commands which the PLC follows i.e. with which the PLC polls the slaves. These commands will tell me how to write the code to handle the data when it sends to my FPGA device. Can you please help me with any suggestions, examples or papers from i can understand more.Please Help me. -Sandeep

Hi Eric I am also doing similar kind of work. But I am not connecting PC to the Allen Bradley Logix 500 PLC but I am trying to connect an external device(FPGA) to the PLC using an RJ - 45 serial cable to the RS-232 port of the PLC. I am very new to these PLC's and I want a small favour from you. Can you please help me in understanding of what changes hsould be done to the PLC so that it detects my device and then what program should I write to the PLC for my device to receive data from PLC. I know that the RS-232 port talks with the help of DF1 Protocol, so how should I implement this protocol in my device , how should i understand the ladder logic program of the PLC, what instructions should I add to the PLC program so that it sends the data (the same data which it sends to modem) to my FPGA device. Could you help me with any papers which can help me or any examples or suggestions or any hints. This will be a great help to me. I am sorry to suddenly interrupt your thread and ask you a question instead of helping you with your problem. As I am very new to this area, I have a very little knowledge of your problem and I feel sorry for not helping you. But please help me with this. Basically I am expecting some list of steps to connect to connect to PLC, PLC detecting my device and communicating with my device. Thanking You -Sandeep

Thank you Rod for your reply.yes, we are using the RSlogix 5000 package series to work with Allen Bradley PLC. Thanks for conforming my questions. Do you or anyone have a ladder logic (for SCadaPack PLC) example of how to make changes in the plc so that it sends data to my FPGA device. (or) any of the RSlogic example(for Allen Bradley PLC) of how should i add some elements in the PLC ladder program so that it starts detecting my device and sends data. Our team is trying to use SCaDApack PLC, so we need to do some changes in Telepace i.e.know how does the ifix MBR driver works, sends data, handles data and do some changes. Actually my FPGA device should receive the data which the PLC sends to modem and then the output which my device gives to the PLC should then be sent to the modem. I hope you understand my question - simply saying the PLC should first send data to my device then my device should do some task and send back the data to the PLC and then the PLC should send that data to the modem. Could anyone please help me in this matter. Thanking You -Sandeep

Hello I am doing a project related to Allen Bradley PLC and SCadaPack LP PLC's. Our team has developed a device(i.e. written a code and implemented it on a FPGA Board) which does some work for PLC. Now we need to connect this board to the PLC and establish a Serial Communication using RS-232 port. I am very new to the concepts of PLC's and after a long study of many papers and manuals related to PLC's, I understood that ScadaPack PLC'c have two RS-232 ports COM2, COM3 which i can used to connect to the device and communicate with. And in Allen Bradley PLC's, there's a channel 0 RS-232 port which can be connected. Is this information right?. And from manuals I came to know that these ports follow ModBus RTU mode serial protocol for communication, is this also right information?. The ScadaPack PLC uses Telepace software to configure these ports and iFix software as an interface to the working of the PLC , my doubt with this when i connect my device to the PLC does the iFix software automotically detect my device or do i need to do soem changes or configuration part in Telepace software, Can anyone please help me with this or provide any documents which can clear my doubts? The Allen Bradley PLC uses RS logix 500 software for interface part. Does this software also directly detecs my device when i connect it to the PLC or do I need to do some changes in it. Can anyone Please help me with this. -Sandeep