Hi all, I am looking for a relay that can switch SEQUENTIALLY through a number of different loads. I have a timer that I want to signal this 'rotary relay' to switch to the next load.
So it would go like...
Timer signal, relay switchs to load 1
Timer signal, relay switchs to load 2
Timer signal, relay switchs to load 3
Timer signal, relay switchs to load 1
Timer signal, relay switchs to load 2...
etc...
This is for a 24V DC system. The loads are only 5 amps, maybe 10.
Hi, don't think you will be very successful looking for a sequential switching relay, the old Post Master General (PMG) used to use devices like that in old telephone exchanges.
You might be easier to use a relay for each output and turn each relay on with a separate controller output.
Or a a serial/parallel chip so you use 2 controller outputs to control many parallel outputs that are each connected to a relay.
If you are only interested in 1 then 2 then 3 etc etc, no jumps or reversal of sequence then 4017 digital IC may help.
You can set it up to switch outputs on every clock pulse that you input to it.
You should be able to google an application sheet for it CD4017.
Hope this helps.
Tom.... 
Bit of an unusual request - I don't know whether you will likely find one in a hurry other than Google which you have presumably tried already.
You could look into individual FETs to do the switching, controlled by a counter such as a 4017, probably requiring a buffer in between. Similarly a couple of the commonly available relay boards (eBay?).
5A at 24V DC - corresponding to 10A at 250V AC (because DC is more troublesome to switch) is a pretty standard relay rating.
Just how many loads are there?
Get three relays.
TomGeorge:
Hi, don't think you will be very successful looking for a sequential switching relay, the old Post Master General (PMG) used to use devices like that in old telephone exchanges.
They were called uniselectors and usually had 5 banks of 25 positions. Overkill for the OP's project, I suspect.
But I've got one, somewhere in my junk pile, if he wants it.
I bought one last year on eBay, it s worth a look.
I managed to get a miniture one, much smaller than the standard units elector used in most exchanges.
The clue to searching is to use the right word and uniselector is the right word.
There used to be a device using a stepping motor coupled to a rotary switch. This was many years ago; I think it had around 10 to 12 positions. I used them for remotely switching the tip and ring of telephone circuits. In this digital telecommunications age, there is probably no demand for switches like this anymore. You might find them in an electronics surplus store, if you're very lucky.
If it were me, I would go to a solid state solution.
Use
One small arduino
3transistors
3 resistors
3 relay
3 diodes
Make before break or break before make are easy to do.
Pelle
Hi, Mike.
Tom......
Pelle list would do the job, plus a supply to run the relays.
You guys suggesting - and it is of course a pretty obvious apparent "solution" - telephone uniselectors, didn't happen to notice that the (so far relatively quiet) OP referred to switching 24V DC at five to ten amps?
pegwatcher:
There used to be a device using a stepping motor coupled to a rotary switch. This was many years ago; I think it had around 10 to 12 positions.
I think they had as many positions as there were numbers on a telephone dial...
They clicked around using the pulses generated by your phone.
If you have a phone with a "hook" you can still dial numbers by tapping it.
eg. To dial "123" you tap it once, pause, tap it twice quickly, pause, tap it three times quickly, pause....etc.
Great for getting around those little locks they used to put on old telephone dials so you couldn't turn them.
Paul__B:
You guys suggesting - and it is of course a pretty obvious apparent "solution" - telephone uniselectors, didn't happen to notice that the (so far relatively quiet) OP referred to switching 24V DC at five to ten amps?
I used to switch stage spotlights with a uniselector. In fact five on diffrent channels, they wer 240V at 5 amps a piece.
Mind you it used to spark a bit. It was in the 60s though, health and safety hadn't been invented then.
pegwatcher:
There used to be a device using a stepping motor coupled to a rotary switch. This was many years ago; I think it had around 10 to 12 positions. I used them for remotely switching the tip and ring of telephone circuits. In this digital telecommunications age, there is probably no demand for switches like this anymore. You might find them in an electronics surplus store, if you're very lucky.If it were me, I would go to a solid state solution.
I think you're referring to a motorised Yaxley switch. Yaxleys were great because you could add 'layers' to make multipole switches. The only problem was, with too many layers they became too stiff to turn.
@Henry_Best - could be. Too long ago to remember (1983). Mine had two layers. In case some folks think micro controllers are a recent phenomenon, this was an early application. A Mostek board on an STD bus with a Z80 uC.
pegwatcher:
@Henry_Best - could be. Too long ago to remember (1983). Mine had two layers. In case some folks think micro controllers are a recent phenomenon, this was an early application. A Mostek board on an STD bus with a Z80 uC.
That would be a "controller" not a microcontroller. The Z80 had no general purpose i/O pins, RAM or program memory built into it.
That would be a "controller" not a microcontroller. The Z80 had no general purpose i/O pins, RAM or program memory built into it.
I'm well aware of what the Z80 was. I wrote tens of thousands of lines of assembler code for it. Some STD boards had EPROM, RAM and I/O on the same board as the Z80. Some boards needed separate memory and I/O boards on the STD bus for an application that needed more memory and more I/O. The all-in-one boards were called single board microcomputers in those days but these boards were used as controllers, of course. There was also a single chip microcontroller with built in RAM and I/O and a socket on top to plug in an EPROM which contained the code. It was called the Mostek 3870.
fungus:
That would be a "controller" not a microcontroller. The Z80 had no general purpose i/O pins, RAM or program memory built into it.
Nevertheless microcontrollers are certainly not recent. How old is the 8048?
Paul__B:
fungus:
That would be a "controller" not a microcontroller. The Z80 had no general purpose i/O pins, RAM or program memory built into it.Nevertheless microcontrollers are certainly not recent.
Who said they were? Not me.
pegwatcher:
I'm well aware of what the Z80 was. I wrote tens of thousands of lines of assembler code for it.
You youngsters don't know you're born....
I've written tens of thousands of bytes of hexadecimal code for Z80. I've patched Z80 code by hand directly on the EPROMS (which is tricky because you can only change 1's to 0's).
6502 as well. I used to feel naked without my little Z80/6502 hexadecimal opcode cards (I wonder what happened to those...)
I've written tens of thousands of bytes of hexadecimal code for Z80
Yes, that too. and lots of machine language with octal on my first 8080 home brew. I had no compiler. I programmed the little 256 byte ROM for that one with a binary counter connected to the address pins and touched data pins with a pick hooked the higher voltage to blow the fuses. Binary- doesn't get much more crude than that.
Ahh, old war stories...
@fungus - if you or anyone else on this thread still has a Z80 on CPM, I have a great Z80 debugger that i wrote way back when. Spent a lot of time on it, some new bells and whistles. Disassembles to a source code file that you can feed directly into an assembler, includes pseudo labels for all references (two pass disassembler).
Frree, of course, to anyone that asks. Also a very powerful programmable editor for CPM os written especially with the programmer in mind. Out of bound-user's-manuals but can give you the formatted text. We were going to market these items, but Bill Gates totally messed up our business plan..