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Basic circuit question

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novice007

New Member
Hi,

I've got a simple electronic project and I'm a novice....here goes.

I'm putting together a 'Totalizer' from RS
Trumeter | Process Control | Counters and Hour Meters | Electronic Counters | Trumeter Panel Mounting 24 x 48

It's fed by a mains 110v supply...I'm looking to incorporate two switches (momentary) that will manually actuate the counter, one for either direction. Resourcing the correct rated switches is proving puzzling to me...not wanting to incorporate any power supply ect components.

What rating switches do I need....???
and how would the circuit look.....how do I connect them up in other words!!!!

Many thanks in advance

M
 

MikeMl

Well-Known Member
Most Helpful Member
Any small (under 1A) switches will work.

The device has a DIRECTION input and a SLOW SPEED COUNT input, you cannot just simply use two switches. The DIR input has to be driven low at least 5usec before the SLOW SPEED COUNT input is driven low to make the 7111 count down.

The attached network should do it.
 

Attachments

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Wp100

Well-Known Member
Hi,

You have specified a counter, the 7111HV, which is an unusual choice for the hobbyist, can I ask what you are counting and why you need high voltage ?

As for the circuit - its shown properly in the Rs datasheet - so cannot add to that.

Your switches need to be rated at mains voltage - but without knowing their method of use is hard to suggest a paticular type.

Think most folk would agree that a mains voltage project is perhaps not the best thing for a beginner to be doing - it kills too easily and you don't get many chances.
 

MikeMl

Well-Known Member
Most Helpful Member
...
Your switches need to be rated at mains voltage - but without knowing their method of use is hard to suggest a paticular type...
No they don't. Look at my attachments. The input signals are isolated low voltage. The open circuit voltage across the switch is 18V with the current limited internally by 3.3megΩ.
 
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Wp100

Well-Known Member
Hi MikeMI,

The open circuit voltage across the switch is 18V with the current limited internally by 3.3megΩ.
No reply from novice 007 but his link does go to the 7111HV module, not the 7111 you refer to.

He could be trying to use 110v AC on the switches - hence me asking about his reason for selecting the HV module ?
 

MikeMl

Well-Known Member
Most Helpful Member
...his link does go to the 7111HV module, not the 7111 you refer to.

He could be trying to use 110v AC on the switches - hence me asking about his reason for selecting the HV module ?
You are right. He is better served by using the 7111 than the HV module. My circuit will not work with the HV version.
 

novice007

New Member
Hi guys,

Thanks for your input....I'm a trainee in my works Engineering dept and the scenario is that what I've discribed earlier....ie 110v mains supply,manual switching required for operator interaction, namely when an item is dispatched into under water loading area, a visual confirmation can be counted by the operator by actuating the sitch...(had in mind mushroom button switch).

The 7111HV has been suggested by an Engineer but I'm trying to see how the system will work. I've been tasked with resourcing the appropriate switch / switches etc.

I'm still studying!!! but would like to get a handle on the above as I've yet to cover such problems.

Thanks again
 

Wp100

Well-Known Member
Hi novice007,

Sounds interesting, can see that the opto isolated feature of the HV version would be a benefit in your works enviroment, but as for switch choice and voltage used to carry the signal I will bow out to others who know all the relevant regulations for a job like this.
 
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