TConnolly

The instruction set of the Micrologix 1100 is different from the instruction set of the PLC/5. The ControlLogix5000 instruction set is advanced and very different from the Micrologix1100. You cannot make a MicroLogix run a PLC/5 program or a ControlLogix program. However, you can make a micrologix control many of the same things a PLC/5 does (with some limitations, particularly on I/O size and program size) and you can make it do many of the things a ControlLogix does, again with lots of limitations. If you need help figuring out how to do what a PLC/5 instruction or a ControlLogix instruction does when there is not a similar instruction in the Micrologix then post a specific question about the instruction - we cannot help when the request is so vague.

I'm betting that both PLCs are faster than the actuators they are controlling.

Sorry, the USB converter will not work. USB-RS232 converters do not support the timing signals required for the converter devices to work. If it were straight through RS-232 then the USB converter would work, but its not.

Can you spread the sort across several scans? That will solve the watchdog problem.

There are a couple of e-bay stores offering an aftermarket converter. If you take a look at them you will see that it is more than just a cable. The communication adaptor requres some electronics - thats what is stuffed into the box on the cable

The SLC 100 is a very old PLC platform. It requires either a hand held programmer or a DOS based progam called PCIS and a communication adaptor. PCIS is available for free and I think there are some people selling communication adaptors, including an after market model, on E-bay. If you search the forum for PCIS and SLC 100 you can find links to get the software and manuals. Edit: Looking at the other thread I'm not sure I did you any favors in telling you that - but I'll leave it at that. You can get a 10 point micrologix for about 90 bucks and the RSLogx 500 software for the 10 point ML is free, you'll still need a communication cable which you can buy or make, but at least an adaptor is not required. I'm not sure what a communication adaptor for the SLC100 will run you, but since this is for education then I submit that spending money on the SLC 100 is a waste - invest it, even if its a little more, in a relevant education instead. Just a thought, selling that SLC100 and Redi panel on Ebay might cover half the cost of a 10 point ML. Factor in the difference you you then not having to buy a communicaiton adaptor and your net outlay might just be less.

I have a modicon 984 using 875-002 4-20mA input. Sensor is a pressure transducer. When the pressure is at 0 the input word from the card tends to roll over backwards to 9999 when the input current drops just below 4.0 mA, ie 3.999 mA reads 9999. This of course creates a bogus pressure reading. To prevent this the transducer has to be calibrated with a slight zero offset, which creates other problems. Has any one else ever encountered a similar issue and how did you resolve it?

And if its not a ControlLogix you can still have one PLC control and poll the device and message write the data to the second PLC (or better yet, the second PLC message reads the first PLC since reads are lower overhead).

The swtich loading of either 120AC or 24VDC inputs is only a few milliamps, so 15W reeds won't be a problem. Just wire them directly into your discrete inputs. If you are using 120AC make sure the switch is voltage rated for it. Whether you need three our four control points and whether a continuous sensor is required is a matter of your application. If your pump will be cycling off and on a lot you may want to consider using four points, one for low alarm, low level turn pump on, high level turn pump off, and high alarm to control the tank level between two points instead of trying to hold it at a single point. This builds some hysterisis into the system so your pump is not cycling quite so much. But it still depends on the application, if the tank level does not change much over time then a single point will be just fine. Even if you do use a single point then you should debounce the swtich, ie, it should be on for a few seconds before the pump is activated, and then the pump should run for several seconds after the level reaches the switch, this keeps tank turbulence from causing your pump to switch on/off rapidly. If your application demands that you hold the tank right at a specific level then you'll probably need a continuous sensor and a VFD drive for the pump.

We mostly use Control Logix, but we do have seven or eight MLs kicking around, just one ML1K, its a bottom dweller so we don't use it. The rest are ML1200. No problems with any of them over at least five years. I can't speak for the ML1500 base units, we use CompactLogix instead, but I haven't ever had a problem with the 1769 IO.

I second the Optimate. But buy it directly from Optimate. http://www.optimate.com/products/optimate/index.html

Upgrade to the 1200, (or 1100). ML1200's are inexpensive and upgrading will likely cost less than other options.

#1) AI software does not require RSLinx. If RSLinx is running you need to exit it, it will tie up the comm port. #2) Even if RSLinx is shut down you might still have problems. Win XP does not grant direct access to the comm port. DOS programs typically used direct access to the Comm ports. You can try running AI in Win98 compatability mode. If that does not work then you will either need a DOS virtual machine or configure your laptop for dual boot.

I've had the same problem. Ultimately I deleted the TrendX object, transfered the Works licnece to the runtime box, re-inserted the TrendX object from the local box, then transfered my Works license back. Its a PITA, but it worked.

If you have device-net or ethernet/IP IO, or are not averse to adding it, then I recommend using a Beckhoff KL3356 module. ~$180 US http://www.beckhoff.com/english.asp?bus_terminal/kl3356.htm

Like my distinguished colleague Ron, I'm going to dredge up an old thread, but this one is about how to pack multiple bits into a single word and unpack them again in your HMI. http://www.plctalk.net/qanda/showpost.php?...amp;postcount=8

That reminds me of when my wife got a ticket for running a stop sign from one of the local revenue... er, I mean police officers. She pled not guilty and went to trial. The officer admitted she stopped but didn't stop long enough. My wife then said the law didn't say how long you had to stop, just that you had to stop. The judge agreed so my wife moved for dismissal and the judge granted it.

I'm sure you could do this with a 555 chip and a simple circuit, but I have to side with Bob. Its better to use a device that has the aproval of regulatory agencies.

Our maintenance technicians are expected to be cross trained. Most have primary skills in one area or another, some are better electricians, some know a bit about PLCs, some are better mechanics, some are better fitters and welders, etc. The maintenance manager will typically assign jobs based on skill set, but sometimes if a mechanically skilled tech is not available then an electrically skilled tech has to turn a wrench. Notice I didn't call them mechanic and electrician, they are all classified as Maintenance Techs. We invest a lot in training. About the only exclusive position is the machinists. All of the PLC programming, hydraulics, mechanical design etc. is done by our engineering group, which lends quite a bit of technical support to the maintenance techs - the two groups are well integrated. We all spend a lot of time hanging out with Bubba, Cletus, Junior and the lot.

There are other things to condisder besides the initial cost as well. Look at your local support infrastructure. If you have good AB local tech support and the local distributor is on the ball, but brand X local support sucks, then it may very well be worth it. OTOH, if the local AB distributor is a bone head and brand X has good local support then, capabilities being equal, pick brand X. In our case the local AB distributor knows their stuff, they stock all the different processors, racks and most of the IO modules, and they have several on staff who deal exclusively with PLCs and software, and there is a local AB office as well - no other PLC maker rivals their support, or even comes close, in this area. But I know that is not necessarily true in other places.

Robh, If you are in the Portland area I know a shop with a water jet machine that cuts panels. It will put a beautiful cut in those SS doors.

I received the following PM. Greetings Ron, I've placed this reply in the open forum so that others can see it and benifit as well as making it visible to forum searches. Open forum post generally get better answers as well as faster answers. No special program is required. The COP instruction is all that you need. Copy F8:0 into N7:0 and N7:1: COP #F8:0 #N7:0 2 To copy N7:0 and N7:1 into F8:0 COP #N7:0 #F8:0 1

Probably not what you want to hear... but I use MSPaint. I set text on transparent backgrounds and use the standard circle and line tools.

Have the button execute a macro. The macro contains a series of IF statements - IF CONDITION == 1 THEN DISPLAY SCREENAME -pParameterFile1 IF CONDITION == 2 THEN DISPLAY SCREENAME -pParameterFile2

I have a SLC5/04 on my desk that periodically gives a solid LED fault. However by disconnecting the battery and flipping the card over, then with a paper-clip shorting from the Vcc pin to the Gnd pin for 30 seconds, I can recover from the fault. That may work in this case, but then agian, it may not work, its worht a try.