Brian
That is it exactly. I am going to use the OOPic to control my engine
throttle and later on I may switch to an analog joysick and use it to control my
rudder and reverse. Who wants to sit dead in the water, waiting for
Windows to reboot? I have not tried it, but C under Linux on a PC104
card should imporve the speed may be much more reliable. Check out www.pc104.org there is a lot that has
changed since I was messing with my robot. And my robot no longer
exist, but parts of it like the DC to DC converter are turning up in my sub
:)
In a message dated 4/3/2005 8:02:56 AM Central Daylight Time,
ojaivalleybeefarm@dslextreme.com writes:
Doug ,
That sounds really neat. I've done some programing in the past and I
have VB on my computer and have only used it on a limited basis. Are you
saying " the down side is the start up speed" by that you mean you
wouldn't want to sit there at the bottom of the ocean waiting for windows to
do its thing? re boot or whatever.
Brian
----- Original Message -----
Sent: Saturday, April 02, 2005 11:00
PM
Subject: Re: [PSUBS-MAILIST] computers
in subs
Brian
I have a PC104 card which is really just a single board Pentium PC
compter with connectors for video, keyboard, mouse, serial, IDE drive,
10/100 network, and a Disk-on-Chip socket all on a card that is 3.5 inches
square. I run Windows98, but any Intel OS could be
used. Other cards can be connected to the main card with a 104 pin buss, so
you buy add-on cards with things like analog to digital converters, and
digital I/O, even GPS and Radio modems. I have a 30 pin Digital I/O
add-on that lets me read switches and encoders, and control relays with the
addition of a driver chip. The code to read and write the I/O lines is
good old VB that uses an API that came with the Digital I/O card. I
have a 3rd PC104 card that is a DC to DC converter that allows me
to power the PC104 stack and an IDE hard
dive from an 8 to 30 volt DC supply. All stacked
together the PC104 stack is about 2 inches high. The price tag
for everything was about $600 and everything but the power
supply came from eBay. I was using this setup to run a
small autonomous robotic vehicle and I programmed and complied directly
on the PC104 by linking it to my laptop with PCAnywhere.
The down side to this is of course the startup speed should the system
crash. If your only monitoring systems then perhapse that is
acceptable.
Given a choice I'd go with Cliff's setup, but since I can not afford
that, I actually prefer the OOPic solution. The code is VB style, the
restart is fast, it has both analog and digital I/O, you can
expand it by adding a second unit. The units can be networked togther, they
can be networked and intergrated to you laptop, and at $89 pluss $20
for the LCD Display, and $5 for a joystick, you sure not going to beat the
price.
Best wishes
Doug Jackson
In a message dated 4/2/2005 9:34:20 PM Central Standard Time,
dr_redus@devtex.net writes:
Brain,
I am not aware of any.
Cliff
----- Original Message -----
Sent: Saturday, April 02, 2005 7:44
PM
Subject: Re: [PSUBS-MAILIST]
computers in subs
Cliff,
Do you know if there would be any way to program a workable system
using VB , I guess you would use a lap top?
Brian
----- Original Message -----
Sent: Saturday, April 02, 2005
9:29 AM
Subject: Re: [PSUBS-MAILIST]
computers in subs
Doug,
My background is in mechanical engineering. This was my
first hands on project with a PLC. I found working with the
PLC to be straight forward. The documentation that comes
with the Automation Direct is detailed and very usable with lots of
examples. Also the tech support from Automation Direct was
great. I think this is generally true for all the PLC suppliers.
Anyone that has done any programming in C, VB or even FORTRAN
(I'm dating my self) would have no problem picking up PLC ladder
logic. My starting point was to make a list of the what I/O I
wanted in my boat such as, for example, an analog input would be a
pressure transmitter for ambient water pressure or tank
pressure. A digital input channel would be something like the
hatch switch or a limit switch or a button on a joystick. An
Analog output would be like a PWM signal to a proportional
pressure regulator and digital output would be, as an
example, a coil on a solenoid valve for air to blow the main
ballast tank. After you know how many input and output channels
you will need, then you can look at the PLC modules and decide how
many you need of each. This will set the number of slots you
will need in the PLC base. My suggestion would be to have a least one
open slot for future changes. After plugging in the modules, it
is a matter of programming each module. My learning curve was
greatly helped by a fellow PSUBer, Alec Smyth, who sent me a copy of
his ladder logic. By studying what Alec had done and reading the
documentation from the PLC vendor, I was able to come up to speed
without to much grief. I did find the instruction set available
on PLC's to be primitive relative to higher level languages such as C
or VB. Most sensor manufacturers offer either 0-5VDC output or
4-20mA outputs. After discussions with an engineer that does a
lot of mobile automation work, I choose to go with 0-5VDC for my
sensors. Anyone with basic skills in electronics ( can use a
multimeter and can solder) can pick this up. As to
PC104 experience, I have none. One suggestion I would make is to
stick with one PLC vendor for all the modules and the touch screen
display. This makes trouble shooting a lot easier. One
other point, if you have any sensors that require RS232 communication
in ASCII, you have make sure the CPU module you pick support receiving
ASCII as some do and some do not. One of the good suggestions I
received from a fellow psuber that had fabricated a psub was to wire
up all the instrumentations and equipment on the bench in
approximately the correct location prior to installing in
the boat. This proved to be very helpful in
debugging everything and in making up the wiring harness
with disconnects. Part of my interest in building a psub was to
come up to speed on PLCs and instrumentation. This part of my
fabrication has been a lot of fun. I did not buy any specific books on
instrumentation. I did do a Google search on basic
instrumentation wiring and found quite a bit of guidance. The
real work in using a PLC as the onboard computer has nothing to do
with the PLC, it is having a good plan of how each ship system is
going to operate and interface with the overall design.
Cliff
----- Original Message -----
Sent: Saturday, April 02, 2005
9:03 AM
Subject: Re: [PSUBS-MAILIST]
computers in subs
Cliff
Yup, that is out of my budget. But I have a friend, and fellow
sub builder that wants to go all out on his control and
monitoring system including the touch screen. So what is the
leaning curve for PLC and the required electronics of sensor
integration? And what web, book, and or training resources
would you recommend for someone with beginner digital electronics
abilities and good object and structure programming skills, but no
PLC?
Is automation control your field of work, or did you develop
this skill for your sub? And so do you have experience with
PC104 ( www.pc104.org) and would that be a
better approach for someone with C or VB experience but no
PLC?
Thanks again
Doug
In a message dated 4/2/2005 8:38:24 AM Central Standard Time,
dr_redus@devtex.net writes:
Doug,
The cost breakdown for the Automation Direct PLC system on my
boat is: PLC hardware $2183, Software $394, color touchscreen
display $745 and joystick $469 for a total of $3791. If you are
patient and know what you want, you can pick up I/O modules on
Ebay at a significant discount. As an example, an Ebay
search string Automation Direct will usually turn up a list of
available PLC modules.
Cliff
----- Original Message -----
Sent: Saturday, April 02,
2005 12:41 AM
Subject: Re:
[PSUBS-MAILIST] computers in subs
Simon,
I know it's out of my league, but out of curiosity, what is
the price tag for that setup?
Thanks --Doug J
Simon,
For the 1 atm sub I have under
fabrication, I am using an Automationdirect (http://web4.automationdirect.com/adc/Home/Home),
DirectLogic 205 series PLC (Programmable Logic
Controller) with a 6" color touch screen display which
is used to interface with the controller and for all gage
displays. The PLC base has 9 modules, 1 CPU, 3 analog
input, 1 digital input, 1 RTD input, 1 analog output and
two relay output modules. The PLC is currently
configured with 20 analog input channels, 12 digital input
channels, 4 RTD temperatures inputs, 4 analog output channels,
and 18 relay output channels. The CPU module (DL 260),
which is about the size of a bar of soap, has two RS232
ports, one of which is used to connect to my
compass/roll/pitch sensor and the other is connected to the
touch screen display. A dual axis joy stick is
used for roll and pitch analog input to the PLC and
a potentiometer on the rudder pedals is used as an
analog input for yaw control. The joystick has 6
switches that I use for blowing and flooding the MBT and
VBT as well as moving the trim weight forward or aft via
a power screw driven by a hydraulic motor. This
setup gives me fly by wire capability. A
laptop PC was used to write the ladder logic, design the
screens and download the ladder logic and screens into the
PLC. All is working fine on the bench and I found the system
to be quite flexible in changing inputs and outputs to the PLC
and modifying display screens.
A PLC was chosen over a hardened
PC for robustness and to minimize space. The PLC is powered
from either the main battery bank (120 VDC) via a DC-DC
converter (120 VDC to 24 VDC) or from an independent
emergency battery pack (24 VDC).
Cliff
----- Original Message -----
Sent: Friday, April 01,
2005 5:08 AM
Subject:
[PSUBS-MAILIST] computers in subs
NEW
TOPIC!!
Who uses onboard computers on their subs? Are
you using modified
trimix SCUBA computers, or homebrew
type stuff?
Simon,
You mean a dive computer or a normal?
On a 1 atm sub a deco computer makes no sense.
If my sub is operational again; I
consider a pocket pc for instument reading ,listing
checklists, gps navigation and as video camera
display/capture.
There are probably more possebilities
and it might save space.
disadvantage: not water
resistant
regards Emile
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