Started programming my PLC

[aquaman49504]

The card monitors 4 inputs so I can monitor the water temp, temp in canopy and temp in control panel. I can then turn on and off fans and heaters as needed. I can also trigger alarms either audible or visual if the parameters are too far off. The PLC really gives an unlimited degree of flexiblity for monitoring and controlling the system. I am not very sure of the programming needed for the sensors, but if I come across the information I need, I will add an analog card and monitor the PH, ORP, salinity(and who knows what else).

 

[perpetual98]

What probes are you using for temperature monitoring? That's the next thing that has me confused. I've found some 304 Stainless steel thermocouples, but they're going to be run between 10-15 feet from the PLC and I'm not exectly sure what hardware I'm going to need to get a temp from the probe to the PLC.

 

[aquaman49504]

You can get thermocouple extension wire and connectors. They are very quick and easy to connect.

 

[horkn]

i am only on month 3 of my career at a water/ wastewater systems integration firm. I order the parts (99% Allen Bradley) for outr company. we use a ton of AB items. you name it SLCs plcs, everything.

My girlfriend is an accounts manager for allen bradley (rockwell automation ) at the downtown location in milwaukee. funny thing is her territory is wisconsin.
while i am green at the whole PLC thing, i will get it figured out really soon. I also plan on going to the automation fair downtown milwaukee next week put on by allen bradley. I will try to get into a few seminars on PLC programming so i know more about the products i am ordering.

I know we monitor many variables in the water for our WWtreatment plant setups. I will see what and how we monitor them. i do know we monitor nitrate, but if anyone has an in with how to monitor water quality, i will be the guy. I have already asked one of our progrmmers how hard it would be to set up a PLC to run a reef tank, and he said "not hard at all- what do you want it to do?" beyond lights, and water changes,a nd top off, pump control, and a couple other rudimentary items i ddnt come loaded with enough questions for him...i will soon, hopefully

 

[aquaman49504]

Please keep me posted.

 

[perpetual98]

The PLC programmers where I work tell me the same thing. I tell them what I want to do, and they say, "Oh yeah, that's easy." Of course they don't tell you anything farther than that. Actually, one of them gave me the ladder code for the lighting. Right now I've got the lighting and top-off ladder logic done, and I'm going to dive into temperature control next. After that, it's pH and ORP control then programming a PanelView so that I can see some of the data.

 

[shouldabenacowboy]

Panelview programming is the fun part....just a few block transfers set up over an RIO connection...OH..unless you have one with ControlNet..then it gets really fun

If any help is needed with AB Panelviews or RSLogix500 let me know

SBC

 

[perpetual98]

I'm not sure how I want to attack the PanelView connections yet. I've got one at home, but I don't have the communication module on it, so I only have serial in or ethernet in. Software-wise, I've got some RSView32 and some RSView SE at home, just haven't played with it yet. More concerned about getting the PLC stuff figured out before I dive into the HMI side of things. I've heard that HMI can be really a pain to work with.

 

[perpetual98]

Here's what I came up with this weekend..... It's a smaller prototype unit that is controlling my nano. I figured it would help me figure some things out before I attack the larger setup.

 

[FuzzyLogic]

Nice clean wiring! I like it. Where did you get the DIN rails and terminal blocks? I can't find any place that will sell them in small quantities.

 

[perpetual98]

We sell all of that stuff where I work. Actually, we make small DIN rail assemblies for one of our customers and I just used stuff that was laying around in our overstock bins.

 

[BeanAnimal]

eBay is a good place for hte terminal blocks. All sizes and shapes. I got a "kit" a few months ago with 2 POS blocks, ground blocks, some fuse blocks etc. I think I only paid $30 or so for about 60 total blocks.

 

[FuzzyLogic]

Thanks Bean. I'm gonna search ebay right now.

 

[Zythum]

Hi,

I am in the process of building a controller myself, part of my "amazing reef on a budget" project. Here are basic ladder programming rules:
Flow of program:

- process inputs
- sequences
- process outputs

I am designing a microcontroller board for my automation duties. I use samples for my components, remember my low cost. You need a real time clock in your PLC to make sure that the time stays right. You could vary temperature, lighting period and such by using a table and interpolating points. I will be doing that with moonlights using a variable DC output (PWM). I will have a 10Mbit ethernet interface and a LCD with keypad. All these are very expensive from known manufacturers, but I want the benefits of these, like the followings:

- Manages power in case of power shortage (I will use batteries with an inverter)
- Alerts me by email on my phone is something goes wrong (electrically, water level, temperature, anything abnormal)
- Analyses the problems and tries to cure them but doesn't over compensate.
- The display tells me (or who knows) what I have to do
- Get the logs to my computer and maybe a webpage but that could affect the stability of the system (I am paranoid sometimes)

So far I am still on the schematic but almost done, I also have most of the parts. Next step will be the assembly on proto board and some cool code in old assembler.

My automated reef will have:
- 24 (17 used) inputs
- 32 (22 used) outputs
- 2 analog DC outputs
- 8 (6 used) analog inputs

 

[BeanAnimal]

I was damn good a VAX assembler (15 years ago).. since that time I have not looked at a single register shift or bitwise op and have no desire to.

I learned inline code and OOP, ladder logic drives me insane and I have nowhere to learn the time tested way of doig things.

Every time I price a PLC, I end up with thousands of dollars worth of add ons. Every try to pin down an ATMEGA128 plan, the pain of learnign yet another language hurts my brain (either assembler, C, or some new goofy basic port).

I have ended up with a PC, 96 bit PCI I/O card, USB I/O cards and a dallas 1 wire adaptor. The program is in visual basic, it runs on windows XP, talks to me, dials my cell phone, serves a web page for data logging and remote admin, sends emails, does light and moon cycles based on the nasa/usno models, and a few other things. It DOES NOT control my top/off, heaters, or other critical life support systems, it only monitors them.

I follow these PLC threads, as I am always looking to see how they turn out. Stable is one nice thing about them. Until I can program one with easy to use language, write a web interface and PC interface, And spend less than $3,000 I just can't see taking the plunge.

Bean