Hey guys,
I posted a question a few days ago about using a PanelView Plus with an AB Micro850 PLC. The response I got suggested that I use KEPServer on the PV+ to communicate with the PLC. Right now I have the Micro850 connected to the PV+ with a 1761-CBL-PM02 and a null modem adapter.
I've tried configuring a project following the "Modbus Applications" document by Rockwell, but the runtime on the PV+ doesn't work. Whenever I try to write to a tag, it gives me an error saying "Unable to write value 'X' to item 'ModbusRTU.PLC.Y", where X and Y are the values being written and the tags. I'm fairly confident that the OPC server itself is configured properly, because the tags I made in KEPServer all showed up in the tag browser in FTView Studio, and when I initially run my application on the PV+ I get an information banner saying "Starting Modbus RTU Serial device driver" "Modbus RTU Serial Device Drive V5.7.336.0".
Since the PV+ is telling me that it's loading the Modbus RTU Serial device driver, my assumption is that it's correctly linked to the KEPServer project which is telling it to use that driver for communications. I'm also confident that the Micro850 is accessible. I had an RS-485 to USB adapter lying around, so I changed the Micro850 from RS-232 to RS-485, connected it through the adapter to my computer, and used Simply Modbus to send it packets. These packets were read correctly, so the Micro850 isn't having problems with Modbus. All the basic settings in Simply Modbus (address, baudrate, parity, address, data bits, stop bits) match the KEPServer ones, with the only difference being that I switched the Micro850 to RS-485 mode so it would work with the adapter.
Based on all this, I'm guessing I have a driver problem. It seems like KEPServer is properly loaded on the PV+ and it has roughly the right settings, but some setting I don't understand is causing the communications to fail. The ID I'm using in KEPServer is SERIAL 1 and that's mapped to COM1 on the PV+, and that's about the only possible problem I can think of.
I'm pretty stumped at this point. If anyone has experience with this and has an idea of what might be wrong, I'd appreciate it a ton. I'm also wondering if there's any decent way to troubleshoot this problem in-depth. The "Modbus Applications" document suggests that you can test the connection using the OPC Quick Client from within KEPServer, but this doesn't make a lot of sense to me. The PV+ and PLC are connected using RS-232, so I don't really understand how running this client on my computer would do anything. Is there a way to set up KEPServer so that the OPC Quick Client is connected (over Ethernet?) to the running application?
I posted a question a few days ago about using a PanelView Plus with an AB Micro850 PLC. The response I got suggested that I use KEPServer on the PV+ to communicate with the PLC. Right now I have the Micro850 connected to the PV+ with a 1761-CBL-PM02 and a null modem adapter.
I've tried configuring a project following the "Modbus Applications" document by Rockwell, but the runtime on the PV+ doesn't work. Whenever I try to write to a tag, it gives me an error saying "Unable to write value 'X' to item 'ModbusRTU.PLC.Y", where X and Y are the values being written and the tags. I'm fairly confident that the OPC server itself is configured properly, because the tags I made in KEPServer all showed up in the tag browser in FTView Studio, and when I initially run my application on the PV+ I get an information banner saying "Starting Modbus RTU Serial device driver" "Modbus RTU Serial Device Drive V5.7.336.0".
Since the PV+ is telling me that it's loading the Modbus RTU Serial device driver, my assumption is that it's correctly linked to the KEPServer project which is telling it to use that driver for communications. I'm also confident that the Micro850 is accessible. I had an RS-485 to USB adapter lying around, so I changed the Micro850 from RS-232 to RS-485, connected it through the adapter to my computer, and used Simply Modbus to send it packets. These packets were read correctly, so the Micro850 isn't having problems with Modbus. All the basic settings in Simply Modbus (address, baudrate, parity, address, data bits, stop bits) match the KEPServer ones, with the only difference being that I switched the Micro850 to RS-485 mode so it would work with the adapter.
Based on all this, I'm guessing I have a driver problem. It seems like KEPServer is properly loaded on the PV+ and it has roughly the right settings, but some setting I don't understand is causing the communications to fail. The ID I'm using in KEPServer is SERIAL 1 and that's mapped to COM1 on the PV+, and that's about the only possible problem I can think of.
I'm pretty stumped at this point. If anyone has experience with this and has an idea of what might be wrong, I'd appreciate it a ton. I'm also wondering if there's any decent way to troubleshoot this problem in-depth. The "Modbus Applications" document suggests that you can test the connection using the OPC Quick Client from within KEPServer, but this doesn't make a lot of sense to me. The PV+ and PLC are connected using RS-232, so I don't really understand how running this client on my computer would do anything. Is there a way to set up KEPServer so that the OPC Quick Client is connected (over Ethernet?) to the running application?