Connecting physical HMI to PLC

[jan.krajniak 0]

Hi everyone: I have been asking many questions recently, and it seems like another one has to be added. My team and I have essentially finished our ladder logic (designed in RSLogix 5000 v15.0.2 to control a 1769-L31 microprocessor with the following modules: HSC, OF4CI, IF4I, OW8I, and IA8I) and have tested it on our laboratory setup. We have also finished the HMI application (RSView Studio Machine Edition, release number 4.00) and are now trying to download the application to the actual HMI (Allen Bradley PanelView Plus 600) and use it to control the PLC. We have managed to download the application to the HMI, but upon actually loading the application, the HMI seems to fail to connect to the PLC. The error that seems to relate to this issue is: (CLXDP) XIP Connection (0) open rejected (Error 2040101) on route to .... . We checked in the help files of the RSView applications, where it indicates that there is either a timeout, the controller is unavailable, or the controller timed out (the "controller unavailable" seems to be the one since the Channel 0 light on the PLC doesn't turn on even though the serial cable to the HMI is connected). We have tried several things, but are at a slight loss right now. Are there any settings which need to be specified before the HMI can run? We have gone through the options on the HMI, and the only category that seems to apply is the "Networks and Communications". Within Networks and Communications, we were changing the settings of RSLinx Enterprise Communications, specifically for the tab Serial-DF1, under which our processor (CompactLogix L31) is listed. We have the driver for the Serial-DF1 set to the following: Use Auto-Configuration NO Device PLC5 Error Check BCC Parity None Baud 19200 Stop Bits 1 Ack/Poll Timeouts 3000 Max Retries 3 Station number 0 COM Port 3 The ComplactLogix Processor Properties are: Address 1 Does anybody have an idea for what could be causing our problems? Thank you very much for your help! Jan

[Ken Roach 194]

I think the problem is the COM port specification. You probably copied these RSLinx Enterprise drivers over from the configuration that you had on the development computer. On the PanelView Plus 600, the serial port on the terminal is COM1. On your development computer, it's probably COM3, which you listed. I would also expect the Autoconfigure to be YES and the device type to be "Logix Platform", but these might work if you're using PLC-5 address emulation in the CompactLogix. Once you've changed the COM port to COM1 in the RSLinx Enterprise configuration on the terminal itself, go back to your RSView Studio configuration of RSLinx Enterprise and check the differences between the "Local" driver configuration and the "Target" driver configuration. The "Target" configuration is what is used by the runtime engine, whether it's onboard a Win2000/XP box or on the PV+ terminal.

[jan.krajniak 0]

Ken, thank you very much for your response! I have followed your suggestions and set the Autoconfigure to YEs, which automatically set the platform to "Logix Platform" and the COM port to 1 (even on the target driver configuration). I also checked the target configuration, and it matches that on the terminal (and even the local, which means that the development computer is also using COM1). However, the HMI still doesn't work when run on the PanelView Plus. It seems like the connection to the PLC fails (yet when run off the computer, the HMI application works just fine). Do you think it might a configuration issue with the PLC/HMI, or maybe I just have a faulty PV Plus? Again, thank a lot! Jan

[Ken Roach 194]

It's times like this I remember the words of Dr. Meredith at Pacific Tech, who said, "Always... no, never... forget to check your references." What serial cable are you using to connect your development PC to the CompactLogix ? Personal computers have "DTE" type serial ports. A-B controllers have "DTE" type serial ports. Therefore, "null modem" serial cables are used to connect PC's to controllers. PanelView terminals have "DCE" type serial ports. Therefore, "straight through" serial cables are used to connect PanelViews to controllers. If you have a "null modem adapter", try attaching it to your PanelView -> CompactLogix serial cable to see if the cable is the problem. and if you're actually at UF, stop by the economics department and tell Dr. Bomberger that Ken Roach says hello.

[jan.krajniak 0]

Ken, I will try and find a straight through cable (or an adapter) somewhere in our building and check if that might be the problem. Thanks for the input! Jan

[jan.krajniak 0]

Hello Ken: Well, it seems like our problem is more deep rooted than that. Essentially, I walked into our team meeting today and the HMI was working perfectly fine. However, at that point we started getting other connection problems. First, the ethernet connection from the computer to the PLC stopped working (without any settings being changed). We have tried to fix the situation, but nothing seemed to work. Again, we are running into the problem of RSView not recognizing the display (we know it was RSView, because RSLogix connected just fine). Then, after a little while, the computer couldn't even connect to the PLC anymore. It seems that the COM1 port (and all the other COM ports for that matter) is somehow failing. Thus, now the situation is completely switched - the physical HMI is successfully connecting to the PLC and controlling the PLC, but the HMI application when run from the computer is not able to do so. It seems like both avenues are not allowed to work at the same time :). I wonder if the laboratory computer is broken and is simply not able to communicate with either device anymore. Do you know if a problem of this type could be caused by the computer or by the PLC (possibly even HMI)??? Thanks a lot! Jan

[Leadcommander 0]

More information required and I will try and help as you must be pulling your hair out by now. PLC L31. Does this have two serial ports or 1 serial and one ethernet port ? PanelView. Does this have only serial port or Serial and Ethernet ? Headup. You should not need to enter the network configuration settings in the Panelview. These settings will be downloaded to the Panelview when sending the file. You will need to select 'Replace Communications' Under your Target mapping in the Communications in RSView development software you should have a Device Shortcut loaded for your PLC. When this is highlighted your PLC in the Target tree should also highlight. This the association is correct. In this tree have the PLC address set to 1 In the PLC have the address of the comm port set to the same number i.e. 1 Also have the PLC comm port set to Point to Point. You probable have this all set but I need to start somewhere to resolve your problems. Cheers

[manav 0]

I have used the PV+ on serial port configuration. I required 3 separate cables for this. 1 for PLC to PC. 1 for PC to PV+. 1 for PLC to PV+. 1 of these cables was standard RS-232 cable. 1 was NC13 cable (as far as I remember). So you would need to check the cables you are using. Even on using these cables communication was intermittent and the client faced massive problems. There are some communication limits faced by the serial ports due to which only one port can be connected at a time. We contacted RA and they suggested converting to ENet. Once we converted all communication to ENet then we never faced any problem. I have implemented PV+ / Logix Pocessor / PC / RSViewME / RSLogix5000 deplyment all on ENet at numerous places and never faced any problem at all. Is your problem Serial port related or something else?

[jan.krajniak 0]

Hello Manav! Yes, I would quite definitely say our problem is serial port related. Also, what you say seems to make sense - different wires seem to make different "stuff" work. For example, we had a wire that is supposed to be "null-modem wire" (so not straight through), and that one would connect the PLC and the PC, the PC to the PV+, but NOT the PV+ to the PLC. I went out to radio shack and bought an RS-232 straight through DB9 female-female (my understanding of NC13). This cable seems to have removed the problem of connecting the PV+ to the PLC, yet now the PC cannot connect to the PLC (from RSView, and even RSLinx has problems recognizing our module) nor can we connect to the PV+ (from RSView, the ENet connection that we have set up to communicate between the PC and PV+ seems to have failed - either the device doesn't get recognized, or we get a "destination is not a valid device" error when trying to download our application to the PV+). So in essence, it seems like our system doesn't want to have two things working at the same time. There is a chance that the problems are being caused by the development computer (because when trying to fix the problem we encountered some strange issues with the COM ports ..), so I will be trying out the connections on my personal computer today. If that fails too, we know its either our wires or something else ... Again, thanks a lot for your input. Jan

[manav 0]

I am assuming that your PV+ would have an inbuilt ENet port. But your controller does not? Is that the case? RA had told me that theoretically the DF-1 Linx driver can co-exist with the driver of LinxEnterprise but in practice it does not work. So you might have to turn off 1 or the other and turn the other service on. Also might have to use separate COM ports. Even with this you might get haphazard errors, like corruption of LinxEnterprise. Driver failed to load. Its a software issue which has nothing to do with cable selection. Trust me i beat my head against this wall enough 3 yrs ago. Even after the project started working properly, after some time there were communication issues between PV+ and PLC. Unless you are using a PLC where ENet is just not available, which should not be the case unless its a very old PLC, just get any converter if PLC does nt have inbuilt ENet port, and transfer entire system to ENet. Throw away all the other serial cables. And then see if it works. The cost might add for the ENet card but convince client its only way to go as i did. I had deployed 2 Flex 1794-L34 PLC + 2 PV+ on serial ports 3 yrs back at a site. I had to spend 2 weeks at the site figuring out why it is not communicating properly before switching entire system to ENet. After ENet system never gave a problem again for last 3 yrs working fine. After that experience I never had the balls to trust serial cables on PV+. So summing up whatever needs a ENet card PLC or PV+ try to get the system on ENet. You will see much better comm performance that will justify the cost add.

[jan.krajniak 0]

Hey manav, thanks a lot for the advice! I agree, personally I would have switched to ENet the second I saw that only a serial port connection would be available. My problem is this: the PLC is not mine, nor am I working for the company (and thus I have no say :) ), which owns the PLC. I am party of a university engineering team (made up entrirely of students) who are working on a project sponsored by a company. Thus, we are bound by the scope of the project as determined by that company, and our tools are also limited by their decision :). THey didn't want to spend the extra money on the ethernet, so we have to deal. We found a way to bypass our problem though - we are transferring all information using compact flash cards. That works fine and fast, and it seems like an easy upgrade/update approach for the company (instead of carrying a computer to the PLC in the plant, they will just bring a flash card with the updated version ...). Again, thanks a lot! Jan

[manav 0]

Glad to help mate....