DL05 Tachometer

I have been handed (beaten over the head with) a project for starting and stopping engines.

Basically goes like this: Engine needs to start if certain conditions are met. Engine also needs to shut down if run above predetermined rpm's.

Engine controls can be handled by 2 or 3 (max) outputs. Rpm's can be read from DC freq at either alternator (preferable) or magnetic pickup. Anciliary controls andshut downs will be added in the future. Will be using AD DL05 or 06 for this project.


Need help. Willing to pay for a jump start on this project.

1st of all I would go for placing an encoder on the engine. The DL05 has a built in 5 khz counter (inputs X0 & X1), So that will require a D0-05DR, (relay output?? and DC inputs).

Personally though I would go for a 105-DR due to the fact that it also has a counter, and a 24vdc aux power supply, and a few more I/O..

The question is..how do you plan on starting/stopping/or controlling the speed of the engine? Gas or diesle?

I have programmed several different PLC's for Diesel Generator Autostart Cranking Panels. Most recently, I programmed an Entertron SmartPak, and have also used GE 9030's and micro's, but haven't tried it with an AD unit. No reason that it shouldn't work.

One reason I like the Entertron unit, is that NO ONE is going to mess with my program.

In the states, crank termination is normlly handled by fuel pressue or oil pressure switches. On occasion, a speed switch is used for crank termination. I am not sold on hooking up a magnetic pickup to a plc input. I have seen some strange things in voltage spikes and ground loops with mag pu's. Less then 5% of then gen-sets I've seen the last 30+ years have used electronic (mag pu) speed control.

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Typical inputs:

Oil Pressue Switch
Water Temperature Switch
Over Speed Switch
Fuel Pressure Switch (for crank termination or shut down)
Manual Operation
Automatic Operation
Remote Start Contacts
Alarm Silence
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Internal Timers:

Over Crank Timer
Oil Pressure Timer
Cycle Crank Timer
Shut Down Timer

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Typical Ouputs:

Over Crank Light
Oil Pressure Light
Water Temperature Light
Over Speed Light
Alarm Horn
Cranking Relay
Fuel Valve (energize to run)
Rack Solenoid (energize to shut down)
Battery Charger Contacts (disconnect charger during cranking)

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NOTES:

DO NOT connect PLC directly to starter solenoid, use a slave relay!

Use diodes or surge suppressors on fual valves or rack solenoids.

Use positive input logic when possible, avoid "nuisance" starts or shut downs if wire shorts.

PLC's are available in 12 and 24 volt operation, to match your gen-set power.

Bob and a few others may have some ideas on OMRON plcs.

regards.....casey

Rpm's can be read from DC freq at either alternator (preferable)

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How do you plan to do that? DC Frequency?

Normally a mag pickup is installed in the set and then goes to a generator controller of some sort to control the speed. A second mag pickup is often installed to go to a relay that gives you above crank speed, underspeed and not overspeed (fail safe). Crompton Instruments make a good one. If you use a decent generator controller it will take care of speed, voltage regulation, load sharing (kW and kVar), load ramp and unload ramp when several sets are on line together. No need to re-invent the wheel here. The best generator controllers I have found are Si-TEC controlers from Brisbane Australia. I will see if I can post the website for you. Here you go http://www.lydatronic.com/~dawsontec/ They are not cheap but are far better than any Woodward, or other controller I have had to suffer.

By the way, 75% of my work is emergency power systems, co-generation, SCTT (soft transfer) and power stations. I have tried most things and, quite frankly, writing a load of logic in a PLC is NOT the way to control generators. There are better things to do in life. Use a real generator controller and make life easy. Mind you, I have been called in to "fix" PLC control of generators. Always put in a proper generator controller and re-write a heap of code. Finish up re-wiring control panels too.

1st of all I would go for placing an encoder on the engine.

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NO!!! See above.

Why try and re-invent the wheel!!!

Casey is on the right track. Please post more information - a spec would be useful.

I will help where I can but without details of what is available from the sets and what you have to do it is near impossible to make many suggestions.

Capacity control can be difficult or easy, depends on what is required.

I have also programmed SCADA systems to write information to the PLCs such as set duty order, start an extra set for a period of time and ignore capacity/load shedding control, etc etc. All can be done but what do you require???

I guess how experienced are you with PLCs would be a good starting point. If you are not accustomed to manipulating all sorts of data, life may be quite difficult.

By the way, my first impressions of the DL05 is that it is a fine PLC but I would prefer a series Omron CJ1 PLCs networked (1 for each set and a master controller PLC).

kelly100 said:

Anciliary controls andshut downs will be added in the future. Will be using AD DL05 or 06 for this project.

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If your even considering future changes/additions to the app. then I would go for the DL06. Additionally you can add a small display to the DL06 for displaying the RPMs or other stuff like that..

Like BobB said, detail is VERY sketchey. One can only presume that it's a generator, but who knows for sure... Try posting a good discription of the project.

ok

Need help. Willing to pay for a jump start on this project.

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Look`s like casey needs to send a bill!
I would say this was a complete start.

kc9ih has come the closest but let me explain a little further. We have several hundred units in the field that use an imbedded microporcessor control panel. While the panel is OK, the price increases are forcing us to look at other solutions. That coupled with the fact that, being an embedded control, it lacks the flexibility we need to customize when required. We may devlop our own panel in the distant future but for right now it will be a plc.

All the inputs need to do is: 1) monitor the state of the diesel engine (running/not running)2)monitor the rpm to guard against over-rev 3)monitor the usual engine parameters (oil press, water temp, etc) from dry contact input 4) start the engine from remote input (dry contact)

All the relay outputs need to do is: 1)trigger 2 slaves to start the engine - one closed till the engine starts then drops out, the other remian closed while the engine is running 2) open slave 2 to shutdown the engine.

These are not gensets. The off the shelf conrols we have don't cut it. I have looked at several dozen.

What I am looking for is the code to start and stop the engine. I've already written the lower half but don't have he time or expertise to write the start, stop, over rev shut down section.

By the way, I do appreciate everyone's input and time.

mike

Mike,

why dont you post what you have done so far? Also since you stated that they are NOT gensets, then plesase say what they are. Do they have glowplugs? What's the envirment? Do they start under load? How is the load applied? How do you shut them off..(injector type)...bla bla bla.. This dosnt sound too diffucut, but info is still lacking.

Post your program and I'll take a look at it.

2)monitor the rpm to guard against over-rev

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Use a crank/under/over speed relay (24VDC auxiliary supply). When the engine is above crank speed turn off the starting solenoid. When the not over speed signal goes off, the engine is over speed and you stop it. So simple it is not funny.

Rpm's can be read from DC freq at either alternator (preferable) or magnetic pickup.

Click to expand...

If they are not generators why did you originally mention monitoring speed at the alternator?

Develop a crank cycle with timers. Normally crank cycles work on 10 seconds crank, 10 seconds rest etc. When the engine is above crank speed, indicated by the crank speed relay, turn the crank cycle off. Normally 3 cranks and 2 rests before fail to start. If it does not get away with 3 cranks it probably will not.
I normally use a prssure switch for monitoring oil pressure. Most engine manufacturers supply digital outputs for low oil pressure, high water temperature etc and you do not need to use analogues, unless analogue monitoring is specified. The switches are way cheaper also and you do not need to use expensive transducers and analogue input cards. Murphy manufacture heaps of monitoring devices with digital outputs for engines.

Keep it as simple as possible.

Mike, I'll post what code I've written first of the week. Its at the office and don't have a copy here. Diesels only need glow plugs to warm up a cold cylinder as they fire due to compression and not ignition. We don't get that cold here in Florida. Shuting the eninge off is very simple. A solenoid valve in the fuel injection pump controls engine off and run modes. The engine will start and run at a preset speed and will not, in most cases, be under load. We've done all this for years and hundreds of time a day. Not a new process (at least not for us). We just need a better control.


Bob, not a genset but anything that has a starter has to have a battery and anything that has a battery has to keep it charged. Hence...alternator. Most are 12VDC but we have larger units that are 24VDC. The current control panel we use monitors revs at the alternator but I'm not married to the idea. I agree 110% with the KISS principal. We've used FW Murphy devices for years. All of their stuff works but is generally old technology, allows easy tampering or is unnecessarily complicated. Look at their A91 auto start unit. It does exactly what we need and we've had to use them in the past but it's a spiderweb of wiring, aux solenoids and can't be used in a master slave control scenario. So adhereing to the KISS philosopy we 86'd the A91.

This project is a lot simplier than I'm probably making it sound and I apolgize if I'm making this difficult.

AHHH!!! Not alternator but exciter.

Crompton have generator/engine controllers also with everything built in.

Have a look here and see if it may be able to be adapted.

http://www.crompton-instruments.com/genset.htm

If you require enough of them they will probably make them for you ay a reasonable cost.

Their crank relay is model 253-PH3W-BGBX-FS-V4.

I think what he was referring to (alternator DC output) was the alternator on the engine for charging the batteries. IF he tapped into the 3 phase in the alternator (got in in between the 3 phase and the rectifiers) it would work ie engine speed = frequency X drive (belt) ratio.

Dan Bentler

A bit general isn't it ? diesels only need heat when cold ? I'll challenge you to start a perkins 4108 in a blast furnace without heat .
I completely agree that this is a job for a dedicated controller that handles all of the control functions . There are so many considerations to properly control a DG set - turbo cooldown , overboost , and much more.
I have installed a crompton engine control center on a big 1500kw perkins set , and I would not like to subject a plc to two big switzer turbo's at red heat half a meter away , and an ambient temperature of around 65C when running hard , the odd splodge of coolent whistling about from the rad header and all the other horrible things bid diesel engines spew out .
Let Crompton have the grief !!

Just out of courisoty, how much $$ is the Crompton controller? If it's considerably more expensive then the PLC, and considering we're talking about several hundred units, then going with the DL-06 may save thousands. Additionally, a GSM modem, or something like that, could be added to the DL-06 for remote monatoring. With the PLC the possabilities are endless, on the other hand with a ready made product, your stuck with what youve got.

Our best price on even a basic Murphy control panel is over $250. Add tach, hour meter, rev limiter, etc. and we're over $400 and still lack remote start/stop capability. Add the auto start/stop and you're into $1000+ plus the nightmare of retro fitting.

Fellas, I appreicate your input but Iv'e done this exercise many times. A PLC is exactly what we need at this point. The working environment isn't that bad. The equipment is outside and all we have to contend with is the ambient temp, rain and vibration(hurricanes not withstanding!). These are simple engines in a simple application.

The cost and time involved in an imbedded solution is prohibitive at this point but may be the ultimate solution down the road.

Perkins engines? Heaven help you...