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Digital Timer 4

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rlee53

rlee53

Mechanical
Aug 18, 2006
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I'm looking for a digital timer that will function as two seperate timers. In other words, has two independent outputs with independent settings. Is such a timer available?
 
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Two standard timers with a common input signal seems to be the easiest way out. But, if you are thinking IC:s, there is always the 556, which is a dual 555.

Is it a ready-to-use unit you are looking for? Or how to build such units?

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
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Sorry, I didn't read well. Digital, you say. The remark about two single units of course still stands.

You could also use a "programmable relay", like Siemens' LOGO! They can offer you up to four digital timers in one device. Separately settable and lots of flexibility.

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
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Thanks. Yes, I am looking for an off the shelf unit as opposed to building something.

I was also considering a programmable relay like you suggested. I suppose one programmable relay would be cleaner and more cost effective, and flexible than two individual timers.

As far as programmable relays go, I know there are several out there; the logo, Teco makes one, I think Omron does also. Is there one that stands out above the others, in your opinion?
 
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I would select any one for this application. The Logo! and the Teco are identical, as far as I have seen. I have used the Logo! (yes, the "!" is part of the name) for a few very simple applications. Setting time from the little front panel is possible for up to four different channels.

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
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Allen Bradley's 'Pico' controller and Moeller's whatever-it-is-called are physically almost identical. Different firmware I think - A-B's software wouldn't talk to the one Moeller unit I have seen. Temptation got the better of me: I had to try, just to see if it did work.

The LOGO! modules are excellent, although it is a long time since I used one. It was pretty straightforward to program, and the LOGO! was the first unit of its type that I had worked with.


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I don't have an attitude problem. You have a perception problem...
 
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The reason why you notice that so many of them look like others it the reality of brand labeling in our new global economy. The Siemens LOGO! was the first on the market and is in fact branded by several other manufacturers, as is the Crouzet (also branded as Schneider/Telemecanique) and Moeller (Allen Bradley) units. The cost to develop these relays is very high and the sales price is low, so those who invest in manufacturing them must move large volumes to keep them viable, which usually means getting them to the market in as many paths as possible.

 
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I think you are right, Keith. Believe it or not, but I did some follow-up work for Siemens on that unit. There wasn't a single person available in Erlangen or elsewhere that knew the LOGO! in detail, so I guess it was developed somewhere else.

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
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Can these save recipe's? I have another project that needs to control and save temperature, pressure, and time. Each job would have a number associated with a recipe.
 
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They are not very good at analogue things. They can measure voltage on two channels (and they are quite good at that) but there is very limited analogue capability otherwise. All there is in them are analogue comparators, triggers, amplifiers and also analogue memory. But no analogue output.

So, if you have a few very simple analogue tasks that switch on/off at a certain temperature or pressure or if you need a pulse train with variable duty cycle as a function of an analogue value, you can use them. You can also have a limited "recipe" function by using two or three inputs to select and activate different blocks in the program. Two inputs let you have four "recipes" and three can give your eight different set-ups. But not sure if there are enough free blocks for that.

Gunnar Englund
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
 
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If its just a dual timer function that is needed, there is no need to go to a programmable relay, although this will give one solution to the problem.
GE Grasslin, presumably among others, produce programmable timers with two and more channels that can be set to switch independently. GE Part nos 666190 or 666191 should be suitable (not that i'm trying to plug GE products, its just that this is what I am most familiar with).
 
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The LOGO! was developed by Siemens US for a very large customer, then "adopted" by Germany (the same is true for the S7-200 micro PLC). That's why you couldn't find anyone over there who knew it Gunnar. Don't forget, Siemens bought Texas Instruments PLCs a long time ago; there are some very talented people over here still.

Once Siemens Germany invested in the LOGO! mass production, they brand labeled it to Idec to help offset the costs. They sell enough of the S7-200's to keep it viable without having to brand label it.
 
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You may use a DL05 DirectLogic miniature plc from automationdirect. The price of 2 timer relays is about as much and you can program any variable operation you choose as well. It's $99 and that is hard to beat considering that a timer relay could cost $40 or more.
 
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As the project evolved, I also needed a few more bells and whistles than originally planned, so I went with a Horner HE-XE130 all in one HMI/PLC, it has a built in HMI, 12 in/12 out and an analog input that I needed for a pressure sensor. Very compact, looks good, room for expansion, reasonable price.

Thanks for all the responses.
 
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