Newbie needs advice

I am just starting R&D on a plc project for controling safety shut-downs for engine powered equipment that we manufacture. I would like the plc to look at engine coolant temp, oil pressure, rpm, etc., as well as as some ancillary equipment In all likelyhood this will involve using discrete as well as analog devices and should be dc in/out.

I ran through the online crash course and am anxious to get started. I would appreciate any advice on selecting hardware/software to get started. I would like to begin with 8 input/outputs but may need to expand in the future

Regards,

Mike

Anything will work, mostly

Gee whiz, almost anything will work.

Based on the little you've said, you'll need a simple
micro-PLC (brick style), with expandability. Mostly
all of the new bricks are expandable.

Consider external communications, if you want to tie
this in to an existing network or computers. This
requirement is usually enough to go to a slot-type
PLC (SLC, 90-30, etc.)

Finally, consider the software. Nowadays, the ladder
diagram editing software is the majority of cost of any
project.

Most everyone will have recommendations, based on their
own experience and bias.

mwkel

If I have understood your post correctly you are looking to monitor power generation units and when curtain safety parameters are breached, ie. coolant temp, oil pressure, over speed, under speed etc, you wish to shut the engine down. Have you considered a dedicated engine monitoring controller?

http://www.deepseaplc.com/

Have a look at the above web site, we have their engine contollers on our power generation units.

This might be an easier solution to your problem, could be worth considering.

Paul

So...

A doctor has this patient. This patient does not exist as the patient would like to exist - coronary, neurological and psychiatric problems, don't cha know.

The patient anxiously says to the doctor, "I want to be this other way instead of the way I am now! What can you do to get me from being this-way to being that-way?"

The doctor does indeed want to help this poor guy.

There is a long pause....

Possible Response #1:
The doctor says, "OK, my man! Let's just throw some of this kinda medicine down your throat and see what happens! If that doesn't work, we'll try something else!"

Possible Response #2:
The doctor says, "OK, my man! Let's start by figuring out exactly what you got and exactly what you want!"

Get my drift?

Thanks for the feedback from the 3 of you.

Let me see if I can put more light on the subject. The units in question are not for power generation but used as a prime mover on a variety of pumping applications. Pumps range from hydraulic to direct coupled centifugal to direct coupled positive displacement, etc. Some are automatic start/stop some manual. These units are out in the field, subject to the elements and are moved frequently. We want to incorporate pump shutdowns into the system as well.

A big concern is the continued use of the equipment past its service interval. In addition to the afore mentioned controls, we would like to have a service indicator that starts off with and blinking LED, progresses to an audible warning and if service still not performed, renders the equipment inoperable until reset by a technician.

Eventually we would like to see our higher end equipment use a touch screen.

My concern is the number of I/Os or is this and "ad infinitum" issue?

Is there an manufacturer that particularly stands out in this type of application or are we at the Ford vs Chevy argument?

PLucas, liked your equipment and web site but nothing seemed to a complete fit for our application.

I think what Terry was saying was add a little more detail to the application. PLC's come with a multitude of options and features you may want to look at some of the more common brands like
http://www.ab.com

http://www.automationdirect.com

http://www.gefanuc.com

http://www.sea.siemens.com
There are other brands too.

Specifically can you state a possible specific number of I/O both analog and digital that would be needed.

What will be the conditions the machinery works in?

As was stated it isnt hard to find a plc works with 24vdc, I think an earlier thread asked once about 12vdc plc's but I dont remember anyone knowing of any. If the system is small there are a multitude of "brick" style plc's that will do what you are asking. Look at Automation Directs DL06, its a little dynamo that even offers an LCD interface ($59) that allows you to change/view settings and display alarms etc. I am redoing a machine with 4 to 5 electromechanical timers with just one of these and havent scratched its memory capabilities.

Anyway this is R&D correct, one of the first step is to determine what you need specifically in the way of I/O and communication connections for an Operator Interface. The other step is too determine conditions it will work it to determine what codes/guidelines must be met...ie is it outdoors, hazardous conditions, desert)hot climate), near/on water (wet conditions), cold etc.? This can determine what type cabinet it must be housed in, what ratings must be obtained. Are you concerned with use in the US only or will it need to be rated for other countries or standards?

If you can give the details as mentioned above these guys can offer more specific advice on what could work for you. Naturally all they can do is offer advice on possibilities, the choice of what to use will be yours. The system sounds small and shouldnt be difficult to fit with a plc to do what you need/want but we dont know all the details yet.

The fist phase of the project is to replace the exisitng electro-mechanical shut-down controls we currently use. This will require 8 I/Os. The unit's electrical system is 12VDC.

Most equipment is in use in the Southeatern US although we ocaasionaly place equipment in Nothern States with cold climates. It will be subject to vibration as well as ambient temps.

User interface will be limited to latching LEDs and a keyswitch for reset. While an LCD display would be nice, I would be concerned about reliability outside in direct sunlight.

I was looking at Automation Direct's DL05?

Regards,

Mike

Looks like the DL05 may be a good choice, it offers a 12vdc power supply option with 12/24vdc options on inputs and 6-27vdc output. They have analog expansion modules which you may need for the oil temp, water temp reading and maybe any other pressure readings involved, for rpm you may need a HSC input which several have built in.

Naturally the same supplier offers a choice on operator interfaces but there may be an issue there with the 12vdc, of course you can install a DC to DC converter from 12vdc to 24vdc.

As far as using the LCD display you could maintain the DL06 in a watertight housing that has to be opened to access the interface when/if an alarm conditions exists. I am not sure this would be "user friendly" but is a simple/inexpensive option.

As was stated this doesnt seem like a difficult project (wish I could get projects like this) and shouldn't be to difficult or expensive.

Let us know if we can assist you more.

Today I recieved an email from mwkelly:
mwkelly wrote on Today 04:40 PM:
Thank you for your comments and suggetions,

After looking a little closer at the DL06 it seems like for the extra $100 or so you get a lot more bang for your buck. Good call on your part. I am reasonably certain that'll be the way we go.

Is there some place I can get examples of counter and timer programs/subroutines. We will need at least 2 in the beginning. One to record total running time for the unit's history and the other to track the time till the next service interval.

Regards,

Mike

My reply [/]
Yes the manual for the DL06, the software manual and the automation website's technical support site. The support site offers FAQ's, applications, example programs and a forum to ask for assistance when you have a problem.

The manual(s) offer extensive help with the HSC (high speed counter) which I assume may will need for your RPM calculations.

Technically what your refered to as needing 2 timers could be done with 1, technically none in a sense. The DL06 has a RTC (real time clock) and calendar along with special registers that are updated accordingly, use of these would probably serve you well in maintaining actual run time and service call time. Everyone sees things different ways, lot of ways to accomplish what I think you need.

BTW I appreciate the confidence enough that you emailed me but if you get a DL06 or another plc and decide to do the programming then make sure you post what you are doing and any problems there, there are many that are by far better at this than I am. If you go DL06 be sure to ask questions on the automationdirect forum because their tech support people monitor it and assist.

All in all I am open to do whatever I can.

Just in case I have mistated or steered you in the wrong direction I will copy/paste this all into the thread you made. The others may have more suggestions, advice and opinion.