Siemens PLC Controller completed

[TropTrea]

Monitoring wise to me is the only reason a PLC would be an advantage. You can take your reading then download them to memory. Later when you hook up your pc you can then download the data and review how much your pH, temp, or any other other factor changed during the time period you recorded it.

But for basic function like controling lights you can get $20.00 timers that work for years, For sump levels there are float switches. Even for dosing you can set up a simple logic cuircuit.

Even on an MRI system with multi mocro computers operating the simple tasks were done by basic logic cuircity. Then for controls FET's are often much cheaper than relays.

Right now I'm phasing in LED's and throwing around some interesting ideas for controling them. Still experimenting with different color combinations but have some interesting ideas on what I want now. The 120 gallon I'm actualy looking at using 6 to 8 drivers that will kick in one at a time so it will step my tank from dark to deep blue on to bright blue then full mid day lighting. and reverse the process for the end of the day.

I also found an interesting Lunar idea. Instead of running moon lights just at night setting them up on a 24 hour 48 minute cycle. This would mean that they are basicly on a 28 day cycle with a different point in the day that they would turn on every day better duplicating the real moon cycle. My only issue here is developing that trigger signal every 24 hour 48 minutes.

Then there the issue of cost. I see here that people start there low cost PLC projects with low cost basic computers but by the time they have everything done there cost was at least 15 times there initial starting point. If you want to add value of there time then the cost become unrealistic.

But with warmer weather moving in on us in Wisconsin my main attention will be more focused on the outdoors till fall. I might get some small projects done and do some planning on rainy days the big upgrades will not be till probably October. With almost 2 acres to worry about, two ponds and gardens my summer months puts most of my big tank projects on the back burner.

Sometimes I wonder how I found time for everything before I retired?

[Dobro7]

Hello all! I was wanting to know if anyone would give me a head start figuring out some PLC programing on a Direct Logic 305 (Koyo)? I just purchased a 210 gallon setup for my son (upgrade from 90 gallon).

I have the PLC mentioned, but have not done PLC programming directly. I was wanting a sample program and see what I can do. We are taking our time setting this up (i am, he is about to beat me).

Can anyone assist with their expertise?

Wish list:

• ATO
• Mix Station
• Water Change
• Temp. Monitoring
• PH monitoring
• salinity monitoring
• LED light control (0-10v)
• etc....

[Kahuna]

Ummm... why? Why would you use a PLC? I am surrounded by PLC's every day and basically, too much horsepower and not enough adaptability to what we do as hobbyists. I programmed an Allen-Bradley Micrologix 1400 to run a tank setup once. The problem is not the PLC logic, it's the I/O, especially probes. PLC's use 4-20mA and 0-10VDC inputs from analog devices such as probes. Temperature is no worries, but I had issues with pH probes.

However, I've experience in PLC programming including Allen-Bradley, Omron, and others including that Koyo of yours. PM me and I'll dig up a sample program.

Kev

[Kahuna]

Originally Posted by TropTrea

Monitoring wise to me is the only reason a PLC would be an advantage. You can take your reading then download them to memory. Later when you hook up your pc you can then download the data and review how much your pH, temp, or any other other factor changed during the time period you recorded it.

But for basic function like controling lights you can get $20.00 timers that work for years, For sump levels there are float switches. Even for dosing you can set up a simple logic cuircuit.

Even on an MRI system with multi mocro computers operating the simple tasks were done by basic logic cuircity. Then for controls FET's are often much cheaper than relays.

Right now I'm phasing in LED's and throwing around some interesting ideas for controling them. Still experimenting with different color combinations but have some interesting ideas on what I want now. The 120 gallon I'm actualy looking at using 6 to 8 drivers that will kick in one at a time so it will step my tank from dark to deep blue on to bright blue then full mid day lighting. and reverse the process for the end of the day.

I also found an interesting Lunar idea. Instead of running moon lights just at night setting them up on a 24 hour 48 minute cycle. This would mean that they are basicly on a 28 day cycle with a different point in the day that they would turn on every day better duplicating the real moon cycle. My only issue here is developing that trigger signal every 24 hour 48 minutes.

Then there the issue of cost. I see here that people start there low cost PLC projects with low cost basic computers but by the time they have everything done there cost was at least 15 times there initial starting point. If you want to add value of there time then the cost become unrealistic.

But with warmer weather moving in on us in Wisconsin my main attention will be more focused on the outdoors till fall. I might get some small projects done and do some planning on rainy days the big upgrades will not be till probably October. With almost 2 acres to worry about, two ponds and gardens my summer months puts most of my big tank projects on the back burner.

Sometimes I wonder how I found time for everything before I retired?

Apologies beforehand, but once the PLC is programmed, you can for all intents and purposes toss the computer unless you're data logging. Most of todays PLC's can write the recorded data to a flash card. Anyone using a computer to store trends should really just spring for a Profilux or Apex.

Kev

[BeanAnimal]

Originally Posted by Kahuna

The problem is not the PLC logic, it's the I/O, especially probes. PLC's use 4-20mA and 0-10VDC inputs from analog devices such as probes. Temperature is no worries, but I had issues with pH probes.

The PH Probe (or any probe for that matter) should be hooked to a dedicated amplifier or conditioner (Foxboro, Walchem, etc.). The intermediate device allows for calibration and profiling of the probe and then sends the 4-20mA/0-10VDC signal to the PLC input.

[Bootlegger]

Wow. Sounds like people from my same tortuous industry. Other than teachers, we are the most unappreciated. I joke that we in the industrial automation and process industries should unionize and let the sewers overflow, the tap water stop, electricity to cease, and leave the oil in the ground.

Anyway, back on topic. Using a PLC is possible as there is a converter card for just about any parameter you'd want to monitor and control. BeanAnimal is right about pH using a amplifier/conditioner. Also, you can buy online (like ebay) a pH probe and industrial controller. I Rep a product by Hach that can ouput a 4-20 mA, 0-5, 0-10V, or just about any digital protocol you want. In fact, in 2-3 more years, just about everything will come with industrial Ethernet and you can push data via TCP/IP. Thus, PC or App ready.