Duffanator

I understand where you are coming from. I always think of it with our conditions taken into account. Our entire plant is washdown so everything eventually gets wet. Trying to troubleshoot a 4-20ma signal that has corroded wires and such would be a real nightmare and also I would think that depending on what you're controlling there could be a personal safety or machine safety element in that. Say your 4-20 mA transmitter is not working correctly or gets wet or has corrosion that is having an effect on the 4-20 mA signal, well then you're binary that you're trying to send is not going to be right so you're outputs are not going to be right. You could be turning something on that's not supposed to be on or vice-versa. PLC to PLC communication on the other hand will either work or it won't work. If it's not communicating then you won't get any outputs. Plus communication works inherently well with binary information because, basicly, that's what it is. Maybe that isn't an issue with what he is doing, but I think that's something to think about. P.S. I like the debate, it's cool that everyone can voice their opinion one way or the other. That can't always be said with forums like this one.

That's a cool idea and it sounds interesting but doesn't that make it unnecessarily complicated and hard to troubleshoot? Imagine trying to figure out why 2 out of the 8 outputs aren't working when it's being fed from and analog signal. That's a downtime disaster waiting to happen if you ask me. I would think some kind of communication option would be better. 232 or 485 to another small plc or something would be much easier to troubleshoot and probably would be much more reliable.

We used to pay a company to come in and do a thermal imaging report on our power equipment, but the cost of a thermal imaging system has come down in price so we finally bought our own and now we do it in house. We set up a schedule so that everything is spread out but everything gets done within a years time. It actually works out pretty good and has helped a lot. It's also very useful in a breakdown situation. Maintenance uses the camera a lot to check for bad motor bearings and such and we use it to diagnose heater head problems or hot spots in electrical contol panels (bad contactors, overloads, etc...). I've used it several times to check a MOD-5 box that we rebuilt to make sure that there are no bad connections. I think the camera was around $7,000 but I'm sure it's more than paid for itself in the few years we've had it.

Here's what I've found. I haven't used any of them personaly, but they seem to fit what you need. http://www.london-electronics.com/process_ld.php http://www.aicpl.com.au/brochures/ldtm200.pdf Hope that helps some

Wait until Windows 7 comes out, that's supposed to be way, way better than Vista. I hope it gets along with all the software I have right off the bat.

We've had a lot of problems with Lightning strikes at our waste water plant taking out the analog cards on our Opto 22 systems we use to trend all of the info out there. We tried insulators and seperating grounds but nothing really worked, it seemed like the lightning was still finding its way through the 4-20mA loops. We put in Banner Wireless 4-20mA transmitters and recievers (They are called Flex Power I think...) and we haven't had a problem since. We had one go bad but it wasn't due to lightning, the box leaked and it got wet :-P We went from spending $5,000 a year on replacing parts for that system to no having to replace anything for 2 years. Maybe you can look into that.

Ahhh, Allen Bradley..... They like to hijak COM ports, maybe they graduated to PCMCIA ports now too

Yes, The SC-09 cable with work with the FX3 CPU's

Good Luck, Panic! You will be missed, I enjoyed reading all your responses. You are very knowledgable and have helped me out plenty of times so I offer you my thanks and wish you well. Good luck in everything you do!

I didn't say that it was a fool-proof solution, I was just saying that you can reduce the chance that a contactor will weld itself "on" if you use a bigger contactor than is required.

I usually oversize my motor contactors so they don't weld shut after cycling power to a big load like a 3-phase motor. If it's something that I want to make sure will turn off I'll use twice the HP rating contactor. Unless space is a major issue I'd do that in this situation if you want to make sure that it will shut off the motor.

I'm surprised your dentist didn't know about that before he did it.

Hey all, First I would like to start out by saying that this forum site is excellent. I love coming here to read all the posts and learn lots of things that I never would have figured out on my own, it is an awesome resource and I'd like to thank everyone that participates. Lately I've felt somewhat unhappy with my current position. I'm and electronics technician and we do a little bit of everything but what I really love to do is programming and networking or anything that has anything to do with that. Unfourtunatly that's about 15% of my job. The rest no longer interests me to be honest. We have 1 projects person in our department and that job I feel would be ideal for me, I'd love to be in charge of projects all the time (I get projects from time to time but not very often). The funny thing is that our projects person refuses to learn anything new, if it's not a Mitsubishi PLC then he wants nothing to do with it. That's fine but I think that if you want to be really good at your job then you need to be able to learn new things. I've tought myself PLC programming, HMI programming, Citect, Opto 22 and some other scale head programming and such (Our company refuses to send us to school for anything, also very frustrating). Much more than our project guy knows and I feel frustrated that I've put the time in and still am not getting anywhere. My question to you guys is this: What would you do in this situation? I would like to go to school for maybe networking or something like that but I'm not sure what route I want to go, I really like doing PLC programing and HMI and SCADA stuff too but I'm not sure where to go for that. I think the problem is that since our company won't send us to schooling of any kind then I have no accreditation or proof that I know what I know. I really respect you guys and I'm sure other people have been in a similar situation, I would like to hear about what other people have done in an effort to try and plan my future. Thanks guys, I appreciate any response!

We do mainly Mitsubishi stuff here so I'm pretty familiar with them, but Allen-Bradley or Siemens or anything like that I am not familiar with at all. I also just started playing with Opto 22 and Citect stuff, but I'm pretty much just teaching that to myself.

I've never done anything with the HMI you are using but do you need to open two ports, one send one recieve that are paired? Like this: Don't forget that the Host station port number is in hex and not decimal.

There is already a built in port for communicating with GX-Developer, you do not have to do any programming or setup in the E71. Just set up the Transfer settings like so:

Yeah, it's the only point on the two scales that is the same. :-P

So you're trying to communicate with the PLC through the HMI? Then it sounds like the new HMI has an incorrect setting. I would compare settings between the new HMI and the old HMI on the machine that you can communicate with.

What operating system are you using? Sometimes Medoc doesn't play well with the new windows operating systems. Also make sure that you don't have some other program open that is using the COM port, and if you use Allen-Bradley software on the PC you may have to uninstall the COM port and then reinstall it to get rid of the AB drivers and use the regular windows COM port drivers.

If you made any changes to your trend tags or anything like that then you have to delete the trend files and let Citect make new ones. If you keep the old trend files then sometimes they don't display correctly. If you didn't change your trend tags then I'm not sure why it would do that.

Yes, the WHILE DO Statement is only needed if you're going to loop the function, but you just want to do it once so you don't need that part. You also don't need to Sleep because the function will just run once and then end until it is called again. The way you have it written it will execute that function once it's started until you shut down Citect. Like Tragically said, all you need it a button that calls the function and it will update the date once and then the function will terminate. That's all you should need.

Use Entrelec terminal blocks, they are much better. The only good thing AB makes, in my opinion, are Overloads and Contactors.

Hey all, I am trending the times when a conveyor starts and stops in Citect and then exporting this data out to excel so the managers can see what times they shut off and turned on. I was trying to figure out how to automaticly calculate the downtime right from the spreadsheet but I can't figure out a way to do it nicely. Does anyone have any ideas? I am calculating downtime right in the PLC, so it's not really a big deal but I think it would be another nice feature to export right to a spreadsheet templete. 2009_05_07_Landing_Conveyor.xls

We have 3-phase motor ground fault detection overloads on, I think, 3 motors out of the 500 or so in the plant. The only other motors we have that have some kind of ground fault detection are the big 150/200 horse power air compressor motors and they are driven off of big soft starts that have ground fault detection built in. Otherwise everything is just standard overload protection and fuses for the wire current rating. Every machine we build or is built for us follows that rule so I'm assuming it's an industry standard. We've had a lot of motors short to ground but none of them have ever caused a problem other than tripping overloads and blowing fuses. Again, the main thing is that the motor is actually TIED to ground correctly, otherwise you will have a problem with the chassis of the motor possibly becoming hot or getting current leakage to ground but as long as the motor is properly grounded there should be no issue.

We just use a three phase overload set to the amp rating of the motor times the service factor and fuses to protect the wires going out to the motor. They do have overloads with built in ground fault detection but they are more of a headache than anything else, they trip all the time for no reason at all. Our entire plant is washdown so almost every motor we have gets wet constantly. The most important thing is to make sure that the motor is properly grounded, if it is and the windings short to ground then the overload will trip out almost instantly. We also like to use IEC overloads and not NEMA because they will actually break the circuit. NEMA overloads will just trip and open up the aux. contact to shut off the contactor but if the contactor sticks then there is still voltage going out to the motor. With IEC the overload will actually break the circuit to the motor and you can also wire in an aux. to break the neutral to the contactor. (Also why it is a good idea to fuse the wires so you don't start a fire!)