Vance
It is not hard to pick up. If you have any instrumentation friends they do this stuff in their sleep. I knew nothing about PLCs and ladder logic before starting my project. It is not hard to pick up. I used a company called automationdirect.com for all my PLC and touchscreen stuff. They are a fraction of the cost of the big boys like Allen Bradley. PLC is just a dumb but bulltet proof computer that is very robust. You plug in modules about the size of a pack of cigarettes for different functions like analog input ( pressure sensors, level sensors, joy sticks, pots etcs.). To talk to different equipment you plug in output modules like an analog output module to say control a motor. You can have digital input and output models for connecting to switches or turning lights on and off. It is actually a lot of fun. I like this system because it is very flexible. To change something like what is displayed on a touch screen or change a set point, you just connect a laptop to the PLC and change the programming language which on most PLCs is ladder logic. What I like about automationdirect.com is they have a very good help desk. They won't write the code for you but just about.
To get started, you make a list of all the I/O you want to run through the PLC like, water depth, water temp, cabin pressure, ... From this you can figure out what modules you need. You then buy a base with enough slots for the modules you picked , pick the cpu and install the modules. I found it works best to add one instrument at a time, program it and see how it works.
The Deepworker you piloted had an on-board PLC. I did not see what brand they were using.
Cliff
Great works are performed not by strength but by perseverance.
Samuel Johnson
Cliff Redus
Redus Engineering
USA Office: 830-663-6445
USA mobile: 830-931-1280
cliffordredus@sbcglobal.com
From: "vbra676539@aol.com" <vbra676539@aol.com>
To: personal_submersibles@psubs.org
Sent: Tuesday, October 27, 2009 4:15:36 PM
Subject: Re: [PSUBS-MAILIST] R300 Dive 3
Hey, Cliff. What language are you speaking? I love the idea (and the price) but I can't figure out where my 9/16" wrench goes in your description.
I use
| Pressure, 0-250 psig, Ambient Water |
Digi-Key (MSP) |
MSP6251P4-1-ND |
1 |
143.50 |
$143.50 |
www.digikey.com |
from
digikey. This sensor sends a 0-5
vdc signal proportional to full scale 250 psi. This sensor is connected to an analog input module in my programmable logic controller. I then display the results on a touch screen display. I
calcualte the depth in the
PLC ladder logic depending on if the boat is in salt or fresh water.
Cliff
Cliff Redus
Redus Engineering
USA Office: 830-663-6445
USA mobile: 830-931-1280
cliffordredus@sbcglobal.com
From: landnseawelding <landnsea1@hawaiiantel.net>
To: personal_submersibles@psubs.org
Sent: Tuesday, October 27, 2009 2:15:18 PM
Subject: Re: [PSUBS-MAILIST] R300 Dive 3
Sounds like you got some good data from that dive. I am looking for a digital depth gauge but the few I have found are for SAT systems and are out of my price range. Where did you get yours?
Rick Patton
----- Original Message -----
Sent: Sunday, October 25, 2009 7:35 AM
Subject: [PSUBS-MAILIST] R300 Dive 3
I have been playing with some of the systems on my boat in between work. This week, I had it out to see how the mods worked. Below is an executive summary of the dive. Visibility was not great at 3 ft and wind was blowing strong so video is not great www.youtube.com/watch?v=wJ_xDXvNuCY but my theory is any day you can get your boat in the water is good day. Jon has added a link to this at my project site at www.psubs.org/projects/1237684922/r300submersible/
On October 22, 2009, the R300 was transported to Medina Lake by trailer to conduct a series of test. There was a crew of 6. This was the third open water dive of the boat. Several first were accomplished, including the first operation of the new motorized ball valves on the VBT with it’s new level sensor, new position sensor on the trim weight, new manual depth gauge, new cabin overpressure valve, new hydraulic system, expanded yaw movement to shorten turning radius, new MBT motorized balls valves, and rebuild jet pump and motor mount to reduce vibration. The ballast systems are now working very nicely. The noise level in the boat is much less. The power consumption of the new hydraulic system is much less. All the new sensors work great. As the water level in the lake was down 48 ft from normal, lake was shallow. I did a test to see that both my digital and manual depth gauges were in sync where I flooded the MBT and then VBT and slowly descended. The gauges were both tacking fine. I though I was in 20 ft of water so when the gauges read, 0, 2 ft, 4 ft, 6 ft and stopped changing, I looking around to try and figure out what was going but could not see a thing. My son who was helping me got right up to the viewport and motioned that I was on the bottom. It was a very soft landing in mud so I did not feel the boat hit bottom.
There were however several issues that came out of the test. This was the first launch and retrieval off a non concrete ramp. This turned out to be a mistake. The front trailer wheel was too small for the rocky ramp and bent. Also the ramp was too steep which caused the back of the trailer to bury itself during launch which made it hard to get the boat out far enough to float off. Also we used a buoy on a line attached to the aft lifting lug as a safety feature to keep track of the boat in poor visibility water. Right after lunch, the rope fouled the jet pump while I was reversing which required an in-the-field tear down and rebuild of the jet pump. After the jet pump repair was successfully made, as the boat was being moved off the beach, the aluminum control arm on the rudder broke which terminated the testing.
Action items before my next dive include, procedure changes so no more launches off non concrete ramps and no more buoy lines for surface maneuvering. Also I am going to fabricate a stronger control arm on my jet pump yaw control. All-in-all, the dive was a great success and a lot of fun. Now if I could just find some clear water to play in!
Great works are performed not by strength but by perseverance.
Samuel Johnson
Cliff