[PSUBS-MAILIST] PLC input question

Alan via Personal_Submersibles personal_submersibles at psubs.org
Fri Nov 4 14:59:57 EDT 2016


Cliff,
sounds like some sensible changes. That hard ballast tank
blowing up could cause a fatality. You have to factor in an
operator taking a "silly pill". I made the cardinal mistake of
trying to dive with the hatch un-dogged. With all the harassment
from inquisitive people at the boat ramp & onlookers it through
my preparation. I motored out with the hatch unlatched because 
it was hot, then in my intense concentration on what I should do
next, I forgot about the hatch :( Got a lot of water in but didn't go
down as I didn't have enough lead at that stage.
   I wonder what parts Psubbers might have lying round if you
made a list of your teams required components.
Alan 


Sent from my iPad

> On 5/11/2016, at 3:48 am, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Alan, yes, the original K-350 plans do have a safety issue with potentially over pressurizing the hard VBT.  In the original plan, the VBT blow, vent and air supply valves are manual with air supply from HP side of internally located scuba tanks.  So if operator took a stupid pill, he could rupture the tank by initiating a VBT blow and forgetting to open either the vent for flood valves.  To mitigate this issue  on the new build, I use the system I use on the R300 which is to use regulated air from scuba LP port.  With the regulator I use, the operator can set the delta air pressure above ambient water pressure.  On my boat I use 75 psi above ambient. If it takes to long to blow the MBT, I can up this valve. To give more room in the interior of the  boat, I moved the two 100 scf scuba tanks outside the pressure hull under the aft MBT in the area that in the original plans has the main propulsion motor.  This space is open now that I removed this motor and have two horizontal aft Minn-Kota 101 thrusters for main propulsion and yaw control.  An alternative solution would be to stay with the HP air to blow tanks but install a pressure relief valve on the VBT tank. An advantage to using the external scuba tanks with scuba regulator is that I hang a BIBS system for both the pilot and passenger off the LP air supply.
> 
> Cliff
> 
>> On Fri, Nov 4, 2016 at 12:23 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>> Cliff,
>> thanks for the update & offer of advice on my upcoming automation choices.
>> That's a huge project updating K350 plans & overseeing the student build.
>> I know we have talked about a plan overhaul in the past. I guess the next step 
>> is building it & then considering the option of replacing the existing plans. 
>> As I remember, the current plans called for components that no longer existed,
>> & had a hard ballast design that would explode if it saw full tank pressure.
>>    Look forward to seeing a video of the R300 diving with it's new modifications.
>> Alan
>> 
>> 
>> 
>> 
>> Sent from my iPad
>> 
>>> On 4/11/2016, at 10:57 am, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>> 
>>> Alan
>>> 
>>> Let me know when you get ready to spec the PLC/HMI, I have been really happy with the equipment I have using and can share.
>>> 
>>> Been working on two Psub projects.  The first is working with a local high school on a modified K350 build.  I spent the last two month detailing the boat with Autodesk Inventor and now have a pretty complete package of drawings and specs for a modern K-350. The original K-350 plans are fairly basic and required quite a bit of reading between the lines.  Changes I made to the original K-350 design were more battery capacity and larger and wider apart battery pods to accommodate, Minn Kota 101 based Kort thrusters like I use for my boat, and totally new electronics including PLC and HMI, full life support including BIBS and added two more viewports.  The MBT system has been totally changed.  I am using two of Hugh Fulton's pneumatic pancake style valves to blow the MBTs and am using Swagelok 3-Way valves to operate the MBT and VBT.  Team is waiting on final budget approval before we pull the trigger on the project.  Team has already received $15K in equipment donations.
>>> 
>>> On the R300, I am in the process of switching control of the compass/pitch/roll sensor which uses RS232 serial communication from  an RS232 port on the PLC base to a dedicated PLC  coprocessor.  I have had some intermittency issues with this sensor over the years and I am trying this to see if this solves the problem.  What I really need is an O Scope that has RS232 investigation feature.  With the work on the K-350 project, I have just not had any spare time on my boat.  Hope to rectify that shortly.  Got a consulting job I have to knock out next week in Oklahoma City then I am free for the rest of the year to play with psubs.
>>> 
>>> Regards
>>> 
>>> Cliff
>>> 
>>> 
>>>> On Thu, Nov 3, 2016 at 3:15 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>> Thanks Cliff,
>>>> no doubt I'll have more questions when I start
>>>> trying to nail down what PLC, HMI & software.
>>>> Have just ordered 2 of those digital to 0-5V converters
>>>> for my remote system. Will give an update on them when
>>>> they are up & running.
>>>> Anything noteworthy on your R300 modifications? (if
>>>> you have time for an update.)
>>>> Cheers Alan
>>>> 
>>>> 
>>>> From: Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org>
>>>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>>>> Sent: Friday, November 4, 2016 5:06 AM
>>>> Subject: Re: [PSUBS-MAILIST] PLC input question
>>>> 
>>>> Alan, for PLC analog input devices, normally they are either 0-5VDC, 0-10VDC or 4-20mA.  You can by analog input modules for the PLC in any of these flavors.  Most popular are 0-5VDC and 4-20mA.
>>>> 
>>>> Cliff
>>>> 
>>>> On Thu, Nov 3, 2016 at 12:06 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>> What is the best sensor input to get for a PLC or doesn't it matter.
>>>> The pressure sensors I am coming across have either 0-5V output
>>>> or some amp range.
>>>> Wish I had heard Jon's talk at the last convention. Was that recorded?
>>>> Thanks
>>>> Alan
>>>> 
>>>> Sent from my iPad
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