JohnM

First step would be to set Output Max to something higher than 0%.

An important thing missed here is that you will need to change the address in the HMI AND also create new MER files to run in the HMI pointing at the new PLC address. Just changing the address in the ENBT can be done online using RSLinx. The address in the project tree is not loaded anywhere it is just good for your records. I have changed ENBT addresses on line before and the PLC keeps on running but you need to have a plan for your HMI. You also need to know if you have any tags communicating with other PLCs as changing the address will break that link too.

If you are talking SE - check the Rockwell Knowledge Database #32953. They have a little ActiveX that you can use to validate the entire HMI database with the controller(s). I know of nothing for ME.

There are modules sold by ProSoft that will read and write between ControlLogix (another for CompactLogix) and GE devices using Ethernet Global Data. One limitation is that only integer data can be used - this is a Logix Backplane limitation. http://www.prosoft-t...logix/mvi56_egd

If you want to eliminate the Router as a source of the problem just get an ethernet crossover cable and go directly from the PLC to your computer. If that works - there is something in the router blocking you. If not - the problem is in your computer and I would procede along the lines of what Ken suggests. Ethernet crossover cables are cheap diagnostic tools that you should never be without.

Yes - the timer time should match the Loop update time.

The timer is there to make sure that the PID updates at the same rate as the setting in the loop. If you changed that timer to 1 second you need to change the Loop Update Time unde the Configuration Tab to 1.0 seconds. This may be done in the code automatically if the timer preset is multiplied by 1000 and written to the tag xxxxx. UPD (where xxxxx is the PID tag). The timer is required unless you are running the PID in a scheduled task (which is the preferred way but not always done). This information is all in the manuals. Without this timer and matching of the loop update time the tuning parameters are meaningless in that they will have no real world relationship to your process time contant.

I think to access RSLinx from another machine you need RSLinx Gateway. I don't think Professional can do that.

The PCMK card only has 2 speeds but the controller and PV could be at 115.2 as well. You can check the PV to see if that is the speed it is communicating at. If that is the case you will not be able to see it with the PCMK card. You will have to use the serial port. If the serial port was set up for a modem you need to set your communciations up manually as autoconfigure will not work.

Just checked through some old posts and found similar issues here. Perhaps there are some clues there - such as the possible problem being RSLinx Enterprise. I run my CISCO in a Virtual Machine (conflict with company network otherwise) which does not have RSLinx Enterprise. I intentionally do not run Linx and Linx Enterprise on the same machine as I have seen it cause problems numerous times. http://www.plctalk.net/qanda/showthread.php?t=36489 http://www.plctalk.net/qanda/showthr...ine+edits+slow Also not asked - what version of RSLinx are you running?

The other thing is that this error is reported if you have not installed RSLinx Enterprise. It is quite common for people to not do this as they seldom bother to read the installation instructions. Is this a recent ME installation? See Rockwell Tech Note 31130 http://rockwellautomation.custhelp.com/cgi...amp;p_topview=1

There is a nice basic tutorial on RSLogix 5000 on this web site. http://www.plcdev.com/allen_bradleys_plc_p...amming_handbook

Is it possible that you may be confusing 3 element Drum Level control with the fact that there are 3 parameters in PID. You need to understand the concept before evaluating if the program is correct or not. There is an explanation of it here: http://www.controlguru.com/wp/p44.html There is also document on the Siemens USA site that explains the basics of 3 element control here: http://www.sea.siemens.com/instrbu/docs/pdf/ad353-105r2.pdf I hope the information helps.

I have to work with multiple software versions too. I found a little freeware (at least for now) utility called WinAudit. I run that on the computers to log what versions of ocx, dll, installed software, etc. are there. It helps to compare what is different on one computer to determine what needs to be upgraded/downgraded to work. WinAudit can be downloaded at the site below. It may help you as it has me. http://www.pxserver.com/WinAudit.htm

Try looking at this thread. I posted a procedure in it that might do what you want. It allows you to dial in to a PC and bridge to the PLC network through it. http://forums.mrplc.com/index.php?showtopic=10291&hl=