24v relay circuit - elp!

[grantr37]

Hi guys,

Need some advice on how to go about building this circuit.

In summary, i fear i may bore you death with the full version, i need to install a DOL with emergency stop and reverse screw capabilities onto a screw feed auger, that is operated by a 24v signal sent from the PLC after the load cells on the mixing vessel the auger will be feeding, has registered the correct weight. The auger spec is 415v, 50hz, 0.6kva (o.48Kw w/ power factor of 0.8).

It has no independent control, just a 3p + e plug tail from the motor which is mounted at the head end of the screw, circa 9ft in the air.

So far my understanding is i need to weld up a mounting bracket to mount this DOL onto and acquire a 24v relay that will need to be added to into the circuitry of the DOL along with the thermal overload.

My question is, and i appreciate the incredible vagueness of what i am asking here: - What exactly do i need to make this work, to have the auger operate under manual stop/start conditions, but also be automatically switched off via the 24v (ac/dc?) signal when the correct weight is registered by the load cells.

Can anyone assist with a drawing, spec sheet, shopping list, some more LSD, winning lottery ticket....

- - - Updated - - -

I know you all love my threads, because they are so fantastically rubbish no one ever knows what im on about, but i always like to try

can we get a photo of this machine, as well as a bit of info on what it will be mixing so that we can get a bit of an idea of the place where it will be used? this will help with design....think this one will take a few days to get worked out in spare time......would say up to a week.....so need an idea of the machine and it's purpose to work out what the requirements will end up being....


this will have to be 200% perfect

 

[Knobhead]

This isn't a job to be designed by random guys on the internet. There needs to be some accountability.

Ben before you get in to trouble over this get some on site advice.

 

[C&H]

Hi guys,

Need some advice on how to go about building this circuit.

In summary, i fear i may bore you death with the full version, i need to install a DOL with emergency stop and reverse screw capabilities onto a screw feed auger, that is operated by a 24v signal sent from the PLC after the load cells on the mixing vessel the auger will be feeding, has registered the correct weight. The auger spec is 415v, 50hz, 0.6kva (o.48Kw w/ power factor of 0.8).

It has no independent control, just a 3p + e plug tail from the motor which is mounted at the head end of the screw, circa 9ft in the air.

So far my understanding is i need to weld up a mounting bracket to mount this DOL onto and acquire a 24v relay that will need to be added to into the circuitry of the DOL along with the thermal overload.

My question is, and i appreciate the incredible vagueness of what i am asking here: - What exactly do i need to make this work, to have the auger operate under manual stop/start conditions, but also be automatically switched off via the 24v (ac/dc?) signal when the correct weight is registered by the load cells.

Can anyone assist with a drawing, spec sheet, shopping list, some more LSD, winning lottery ticket....

- - - Updated - - -

I know you all love my threads, because they are so fantastically rubbish no one ever knows what im on about, but i always like to try

you'll need a separate reversing contactor for a start, make sure the forward contactor is wired through the n/c auxiliary on the reverse contactor and the reverse is wired through the n/c on the forward so the 2 contactors can't be pulled in together lol. you can get forward/ reverse kits in suppliers.

e stop should be wired in series with the overload on the contactor, n/c connections 95+96. wiring into pre programmed plc's can be problematic, may show a system fault if its not run in the pre set sequence. can't see there being a problem so long as the auger automatically starts when the 'feed' to it (is it meal?) applied.

if there is nothing going through the auger it will cause no H&S problems ie once the feed is stopped the screw can turn all night long, its not going to block anything up. make sure the e stops are sited correctly and good luck i get threw into jobs like this all the time!

 

[wade88]

Ok guys, taken all your advice on board completely.

Tony, harsh but fair (as usual).

Shake that blow to the head off and moving on...

I have been dropped in on this one, as the company building this machine we have contracted them for, have over looked the auger control issue, and emailed through asking if Ben can "add a 24v relay in the circuit somewhere to accommodate the signal cable" almost verbatim that.

After emails back and forward, phone calls to their electrician, and discussions with our build consultant the general consensus has just come back as such:

The auger needs forward and reverse for loading and then cleaning pruposes, it needs an emergency stop, it needs to accept a command signal from the PLC that will be delivered via this 24v signal wire.

That is all i know.

This auger is not going for re-sale onto any markets, it is used in house by operators, if i had it my way, which i am trying, i do not want any involement from this PLC as a known amount of material is going to be loaded manually into the hopper, thus making the need for automatic weight control redundant IMO, the operator should simply start and stop the machine via the DOL like all our other augers here. However...the machine design team are saying the PLC sequences have been written and altering it may affect the down stream processes significantly.

So. You all now know as much as me. The auger spec i have given, that is all i need to know.

I understand that coming on here for a solution is not ideal, i appreciate that, but for me who has had to learn pretty much everything i can from this forum, i was interested to hear the opinions of guys on here as this is the biggest resource of information available to me otherwise i just don't know where to go to get help on such matters.

They are sending their electrician down to assist, but he has stated he doesnt know the end solution either..... brilliant.

Blind leading the blind a little....a lot.

The national wave of *sighing* i can hear from my desk, sorry.

My plan was to wire in series, a 24v mini contactor relay to that box i have bought with the forward/reverse/em stop as the board is designed to accept further accessories.

I'm sighing a lot myself this morning.

 

[wade88]

you'll need a separate reversing contactor for a start, make sure the forward contactor is wired through the n/c auxiliary on the reverse contactor and the reverse is wired through the n/c on the forward so the 2 contactors can't be pulled in together lol. you can get forward/ reverse kits in suppliers.

e stop should be wired in series with the overload on the contactor, n/c connections 95+96. wiring into pre programmed plc's can be problematic, may show a system fault if its not run in the pre set sequence. can't see there being a problem so long as the auger automatically starts when the 'feed' to it (is it meal?) applied.


if there is nothing going through the auger it will cause no H&S problems ie once the feed is stopped the screw can turn all night long, its not going to block anything up. make sure the e stops are sited correctly and good luck i get threw into jobs like this all the time!

Thanks C&H, it is meal yes, more like biscuit mix, high flour and wheat percentage, sugar etc, granulated, quite course but a "flowable" material.

Fortunately the item i have bought has forward/reverse and EM stop all pre-wired, it is a one stop solution, it just needs a 24v relay retro fitted to it to accept the 24v command signal

 

[wade88]

Buy DOL & Star Delta Starters Reversing DOL starter,5.5kW 415Vac Telemecanique LE2GBKO55N7 online from RS for next day delivery.

there it is again

 

[Spoon]

Fortunately the item i have bought has forward/reverse and EM stop all pre-wired, it is a one stop solution,

IMO what you have is a Stop and not an Emergency Stop.
EM Stops should have a yellow background and may stop the motor differently to a normal stop. All depends on many factors..
These people are not giving you lots of info and at the end of the day you are putting your name down to the design. If anything goes wrong and someone gets injured then you are the one that everyone will be pointing their fingers at. "he designed it... its all his fault..."

 

[netblindpaul]

...This auger is not going for re-sale onto any markets, it is used in house by operators...

Wade if you read my post I never used the term "sale".
The statute law regarding this defines putting onto the market as putting into use, whether this be internal to the company who made it or not.

If you are building a machine for use in an enterprise of any sort it must comply with the requirements of the relevant new approach directives,etc. and the UK statute law that applies, e.g. EAWR, PUWER98 etc.

It matters not one little bit that it is the company who is designing & building the thing that is going to use it, the law states that it still MUST meet the requirements.
If you & your employer choose to commit criminal offences then it's your shout, but you should be aware of what you are letting yourself in for.

 

[C&H]

Wade if you read my post I never used the term "sale".
The statute law regarding this defines putting onto the market as putting into use, whether this be internal to the company who made it or not.

If you are building a machine for use in an enterprise of any sort it must comply with the requirements of the relevant new approach directives,etc. and the UK statute law that applies, e.g. EAWR, PUWER98 etc.

It matters not one little bit that it is the company who is designing & building the thing that is going to use it, the law states that it still MUST meet the requirements.
If you & your employer choose to commit criminal offences then it's your shout, but you should be aware of what you are letting yourself in for.

are you a glass half empty kinda guy lol

 

[wade88]

Wade if you read my post I never used the term "sale".
The statute law regarding this defines putting onto the market as putting into use, whether this be internal to the company who made it or not.

If you are building a machine for use in an enterprise of any sort it must comply with the requirements of the relevant new approach directives,etc. and the UK statute law that applies, e.g. EAWR, PUWER98 etc.

It matters not one little bit that it is the company who is designing & building the thing that is going to use it, the law states that it still MUST meet the requirements.
If you & your employer choose to commit criminal offences then it's your shout, but you should be aware of what you are letting yourself in for.

Sorry i just misunderstood your post mate.

Yea thats been drilled home well enough now. I understand the point your making.

I frankly was unaware it was a criminal offense to install a start stop circuit for an auger....all i am asking is how to integrate a 24v relay into that.

 

[wade88]

said with only the slightest sarcasm but genuinely, thats all that needs to be achieved here, i do not believe we are breaking the law. I must have explained the situation badly.

Tele, i have givurn upp on eforts to maintane reesonoble spellin and gramah. Cant be ahsed.

 

[netblindpaul]

Wade,
You are NOT "just" installing a start stop circuit, you are modifying safety systems in the control circuit.

If you have never been part of a serious accident investigation then think yourself lucky, once you have, you'll think differently, trust me.

You must realise that safety circuits are covered by statute law, and if an emergency stop is involved, then it is a safety circuit.

C&H,
NO I AM NOT A GLASS HALF EMPTY KIND OF GUY I DO THIS FOR A LIVING.
DON'T BE A***E.
When are you lot going to realise that safety systems are covered by things it seems that most members here don't understand.
Forget BS7671, this is not even relevant.
There is so much more to consider than the electrical side.

I can't believe that there are so many posters on here that obviously have no clue with regard to the design of safety related parts of control systems, yet you profess to be experts & do this all the time apparently.
I hope you have damn good PII, and that you can give your PI insurers the proof that you have undertaken due diligence when things go wrong, that you have access to all the relevant A, B & C standards for the equipment you are working on.

I am flabbergasted, is all I can say, this is unbelievable.

 

[Knobhead]

Ben, you seem to think Paul and I are out to get you.

Nothing could be further from the truth. My feeling are at the moment are that you can stew in your own juice.

I wash my hands of the whole affair.

 

[grantr37]

Wade, You are NOT "just" installing a start stop circuit, you are modifying safety systems in the control circuit. If you have never been part of a serious accident investigation then think yourself lucky, once you have, you'll think differently, trust me. You must realise that safety circuits are covered by statute law, and if an emergency stop is involved, then it is a safety circuit. C&H, NO I AM NOT A GLASS HALF EMPTY KIND OF GUY I DO THIS FOR A LIVING. DON'T BE A***E. When are you lot going to realise that safety systems are covered by things it seems that most members here don't understand. Forget BS7671, this is not even relevant. There is so much more to consider than the electrical side. I can't believe that there are so many posters on here that obviously have no clue with regard to the design of safety related parts of control systems, yet you profess to be experts & do this all the time apparently. I hope you have damn good PII, and that you can give your PI insurers the proof that you have undertaken due diligence when things go wrong, that you have access to all the relevant A, B & C standards for the equipment you are working on. I am flabbergasted, is all I can say, this is unbelievable.

I was thinking of around 30 pages of schematic diagrams, 10 pages of mechanical working diagrams, detailed risk assessments and statements (around 30 pages) a user manual (10 pages or so) a maintenance manual (25-30 pages) as well as various calculations and logic diagrams, code for the PLC, safety interlock designs, floor layout and working zone diagrams, assembly drawings, a PCB design and component layout.... End user operating manual and cleaning instructions, as well as modification to PLC firmware incorporating a maintenance and cleaning mode, also overload and jamming protection and end of shift lock off to securely power the unit off... then handing those documents and designs to the office to get somebody else higher up to seek advice off the back of them.... a lot of bother, can an off the shelf unit not be purchased? had a think about what netblindpaul said and maybe it would be unwise for one of us to design something over the internet when we don't know 100% for sure how it will end up getting changed around...can do without some factory worker getting turned into a box of biscuits....

 

[Knobhead]

Sorry i just misunderstood your post mate.

Yea thats been drilled home well enough now. I understand the point your making.

I frankly was unaware it was a criminal offense to install a start stop circuit for an auger....all i am asking is how to integrate a 24v relay into that.

So absolutely nothing has sunk in?