What PLCs are being used in coal mines?

Thank you in advance!

What PLCs are being used in _______________ applications? (You fill in the blank with whatever application you desire)

Any specific application is not limited to one particular PLC.

It kind of depends on local resources and preferences. I'm sure if you examine coal mining world wide, you'll find every major brand of PLC in use somewhere.

OZEE said:

What PLCs are being used in _______________ applications? (You fill in the blank with whatever application you desire)

Any specific application is not limited to one particular PLC.

It kind of depends on local resources and preferences. I'm sure if you examine coal mining world wide, you'll find every major brand of PLC in use somewhere.

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Thank you for replay OZEE. I understand you answer. I myself used PLCs application - on electric power substations, in road tonnels, to control vagon-turner to reload coal and so on.

However coal mines have own specific. There are tough requirements to anti-blast protection. For example, in Russia there are requirements to digital input lines (there are limitations on voltage and current).

So I would like to repeat my question in another form.

What concrete PLCs are being used in coal mines in USA, Australia, in other countries?

I invite representatives of producers of PLCs to show concrete examples. I expect something like

In USA, state XXX, city YYY, coal mine ZZZ controllers CCC produced by firm FFF are being used for (application).

Depends of customers preferences.

Some use ABB (Linkmann), actually a lot use it. And of course Siemens (PCS7 with or without necessarry addons).
Sure ther are more but these once are quit common, at least in the places where I'v been.

Best Regards

Henk

HenkieD said:

Depends of customers preferences.

Some use ABB (Linkmann), actually a lot use it. And of course Siemens (PCS7 with or without necessarry addons).
Sure ther are more but these once are quit common, at least in the places where I'v been.

Best Regards

Henk

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Many thanks Henk!

Our firm is completing a big enough project on coal processing plant in Western Siberia. So 2 day ago we were approached to elaborate reliable and SAFE solution to control conveyors inside a coal mine. Russian regulations in this dangerous area are very tough. All equipment must be in explosion proof enclosures. Power supply must be no more than 15V. All devices must be spark-proof. And so on and so forth.

I fancy that in SA, USA, Canada there exist similar regulations. And some special variansts of brand-name controllers fit the regulations.

I was surprised to know that there are only 2 Russian firms with their home made "controllers" that share (fast developing) Russian coal-mine automation market. So I seek reliable solutions.

Any brand of PLC can be used inside a flame proof enclosure (we use AB PLC5,SLC500,CLX) in a various peices of equipment. The "trick" is to have a barrier which limits power between the plc and the hazardous area. such as those made by MTL, Pepplr & fuchs.
Use design engineers that know this type of equipment and inherient dangers.

kellian said:

Any brand of PLC can be used inside a flame proof enclosure (we use AB PLC5,SLC500,CLX) in a various peices of equipment. The "trick" is to have a barrier which limits power between the plc and the hazardous area. such as those made by MTL, Pepplr & fuchs.
Use design engineers that know this type of equipment and inherient dangers.

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Thank you Kellian!

Thank you for very informative replay.

Frankly speaking I was absolutely sure that virtually any (of course reliable) PLC fits the task and there is no need to invent 'special' controllers dedicated to coal mines.

Interesting, is there even one example of coal mine (with exact address) where Schneider Electric controllers are being used? Local representatives (here in Moscow) mentioned namely Australia in this context (though without any details).

I fully agree with Kellian, however you have to take a few things in considaration when using barriers. A barrier has a very low signal on both sides of it. Just be carefull when choosing io cards. Two weeks ago I did an unplanned S5 to S7 upgrade off an ESD system (Emergency Shut Down) on a Chemical plant. (Normal) Analogue plc cards sometimes can pull down the barrier... in this case you need amplifiers (like the Phoenix Contact ones) to get a proper reading.

Just be aware of this.

HenkieD said:

I fully agree with Kellian, however you have to take a few things in considaration when using barriers. A barrier has a very low signal on both sides of it. Just be carefull when choosing io cards. Two weeks ago I did an unplanned S5 to S7 upgrade off an ESD system (Emergency Shut Down) on a Chemical plant. (Normal) Analogue plc cards sometimes can pull down the barrier... in this case you need amplifiers (like the Phoenix Contact ones) to get a proper reading.

Just be aware of this.

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Thank you Henk, I will take it into account and will be very carefull.

Any brand of PLC can be used inside a flame proof enclosure

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Yes, but what if you have to maintain the PLC that is situated in such an explosion-proof enclosure ?

I have only limited experience with explosion-proof systems.
My guess is that you would have to situate the main control system outside the dangerous area. From the control room you wire out to the sensors in the dangerous area via EX-i (intrinsically safe) networks. At least Profibus exists in an EX-i approved variant.
Supply to motors and other power circuits would have to be via EX-d approved equipment.
There are several other methods, but I think these are the most commenly used.

http://en.wikipedia.org/wiki/Electrical_Equipment_in_Hazardous_Areas

I have seen Control Logix used.

I helped out on the motion control part of an automated coal mining machine. It would bore into the sides of mountains. There are two Control Logix PLCs and two motion controllers. All were connect by Ethernet/ip. There was one Control Logix and motion controller that were in a support car just behind the miner. The miner and the support car had to move in an inch worm like fashion. The motion controller had to carefully measure the distances the miner or cart moved and the control logix kept track of the changes in position so the miner always knew where it is. This is very important as GPS doesn't work underground. No people went under ground. The main motion controller and PLC where outside. They controlled loading the carts that went behind the miner and support car. The miner had a roll with spikes that would do the digging. I believe this miner was heavier than the heaviest of miliary tanks. The carts were driven into and out of the hole by a drive shaft that would link from one car to the next. Another drive shaft moved the conveyor that removed and moved it outside. As the miner dug farther underground the motion controller would back of the the two motors that drove the shafts and insert another cart. The drive motors would then make contact with the drive shafts and push the cart in as the miner went in. There is one operator and one person loading the carts. The whole outside structure can walk after the carts were with drawn. This was also one of the first wireless projects I was involved in. The operator could walk around the cab and inspect but still monitor the PLCs and motion controllers via a wireless tablet. I believe Rockwell made that too. It was expensive but it had a long range outside because there were no building around.

This was a very ambitious project. A few PLC programmers tried and failed to make this project go. Finally a Rockwell engineer got involved and finished it up. He was on site most of the time and for many weeks. I only remember his first name, Chad. I called him superman because he was doing the job of the previous 2 or 3 failed programmers. He just had to pick up the pieces and make it go.

The last I heard the machine was still working but some of the cart loader part was being done in manual because the position feedback devices didn't hold up.

SNP,
We have a Schneider Quantum PLC inside a coal mill building that is ClassII DivI designated. I personally don't think it was properly installed as the airtight box can be accessed and left open.
My location is Ontario Canada.

Peter,
Do you remember the manufacturer of the wireless equipment you were talking about? We are playing with some ProSoft units right now with good results.

Sliver said:

Peter,
Do you remember the manufacturer of the wireless equipment you were talking about? We are playing with some ProSoft units right now with good results.

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No, I think it was nothing more than a wireless access point connected to the Control Logix Ethernet. This was about 5 years back.

I understand that it is silly and even stupid question but is anybody aware about reliable Western producer of explosion-proof encosures that are being used in coal mines?

For me it is the main question.

Try to google for "explosion proof enclosure".
But be warned that there is a BIG difference between EEX-d and EEX-e for example.
You cannot just stuff a PLC inside an EEX-e enclosure and then call it explosion proof.
And I think that it is impractical to install a PLC in an EEX-d enclosure.

I think you should start with some basic training in EEX terms and techniques. It is too early for you to search for specific parts.