I need a digital counter which has the ability of sending the acknowledgement signal on one of its outputs! I need to be 100 percent sure that counter is incremented when button is pressed or some other event ocur! When counter is incremented electrical signal must be send to one of the counter outputs so that some other device can know for sure that the counter was inrcemented.
Where can I buy counter with this ability or if not how can I modify one of the existing counters to act like I want and need???
Depending on your frequency requirements a microcontroller will do it easily.
As an alternative you can use a standalone counter with a communication port (BCD output or even RS232 or GPIB output), and just read the displayed value with one of these ports to check if a change as happened...
What is the application about ? May be could we help more...
"Baroje" a écrit dans le message de news:br9csa$lqf$ email@example.com...
But what don't you trust about the counters that you need this flag? Unless you have a really odd design (ie there is an input to the counters from somewhere else so you can't guarantee that each button press does count), once you've got a good design the counter will increment each time the button is pressed.
If you don't trust the button press, ie the button is flakey, then you add circuitry so each time the button is pressed, there is a short audio beep.
If it's really that you need a strobe for something else when there is a button press, then you use the button press signal as the strobe.
Like I said on the other group, it is about distance control. When the button is pressed and the counter increments someone else who is not in the same place must know that the increment did ocur. He do not know the state of the counter, he only need to know that increment was performed correctly!
I don't know how this will work since I don't have a computer present (RS232). Do you think it could be done by connecting a reley on that output you are talking about, and when the increment ocur the reley can for example turn on the light bulb!
What I need is a singal from the counter and not from the button. THe button is pressed OK, I trust that, the counter increments and here I need confirmation so that for example on same distance, where I cannot see the counter I know that counter realy did increment. Important thing is that I do not need to know the state of counter on the distance but only did it or did it not increment!
It sounds like you are trying to communicate information instantaneously. Maybe possible on a useful basis in a couple of hundred years time, but in the meantime you need to control the expectations of the people who want you to build a star trek style teleporter.
Then monitor the state of the button signal at the point where it enters the counter. If you can not trust that your counter increments when it receives that button-press signal, then you have a defective counter.
It's just that simple.
And what specifically is the application about? Can you describe what is being counted? Where are these people standing or sitting? What do they see? That sort of thing. We're all insatiably curious, you know. :-)
This application is about railway safety. My customers want to have double security and there is nothing I can do. It needs to be done no mather what.
It is something like this. The trains are passing through the station or the switch and we are counting them. That's where I need a counter. The counter is either automaticaly increment or by the railway staff on the station. For some reason the bastards on the railways want to have a electrical signal from the counter to confirm its incrementing, they do not want to confirm the incrementig using the input signal in the counter. They say somethin like this: " Ok, there is input signal and after that the counter is incremented, BUT what if there is somekind of error (due to weather or any other reason) and you have an input signal but the counter does not increments itself. We want to have independent (independent from input signal) confirmation of the incrementing"!
It is very important from the safety stand to be absolutely sure about the number of trains in one rail section!
Seems fairly straight forward. I think the answer has been given before though. You'll need some sort of clock to register the LSB of the counter. Then compare this register's input and output with an XOR gate. You'll get a '1' out of the XOR gate for one clock period after the counter increments. If you really want to look for the entire counter incrementing you can register the entire counter, add 1 and compare to the current value of the counter.
What would happen if the counter made a spurious extra count? For example train systems are noisy environments (lots of high currents and voltages flying about). If you have long wires it wouldn't be hard for noise or perhaps a local lightening strikes to cause "extra" phantom button presses.
I suggested using a small microprocessor in an earlier reply and now I'm going to suggest you use TWO!
Let's call them the "Button micro" and the "Counter Micro" - put one at each end of the wire.
Arrange it so that both microprocessors maintain the same count. When the button is pressed the "button micro" increments it's count and sends a packet of information down the wire. The packet could contain the new count and perhaps a message telling the counter to increment or decrement it's owb copy. The counter micro should increment it's counter and compare the result with what the button micro said. If they agree then the Counter micro can send an acknowledgement message back to the Button micro to say "I got that one thanks". Add some extra code and it's easy to ensure that both micros check each other is working ok. They can even send each other test messages when no button presses occur just to check the wire isn't broken or the power failed at one end (eg "you still awake messages?) .
If there is a power cut at one end it can even ask the other end what the last count was when power is restored.
Many micro like the PIC series have UARTs or serial interfaces of other sorts in them to make this easy.
The system could also be made expandable. For example what happens next month when they change their minds and want TWO buttons and two counters but you have already installed only one wire? It's simple you just make the counters addressable and they share the wire. Many micros have addressable serial interfaces for this sort of thing.
What about a mechanical counter? Less prone to misfires from electrical "noise", cheap, durable. Maybe put a microswitch inside the counter that gets hit by the mechanism inside the counter. If the microwsitch gets a closure at each count, you know the counter actually incremented. Could maybe use two counters for redundancy.
How much money do these people have? What kind of display? Point an array of photodiodes, or a CCD camera at the displays, and analyze its output. When one of the digits changes, you've counted. Actually, you only need to watch the LSB. Maybe a tiny photodiode very close to each LED segment. If it's an LCD, then you'll probably have to look at the input signals, unless you have a photosensor that can read an LCD. Otherwise, tear into the circuit and monitor the outputs of whatever's driving the display.