Hello
Please find herewith information on the float switch that has been built to provide a "Butts full" indication / signal.
This switch is intended to be a quick fix to allow system and software development to go ahead on pumping water between butts and sump, until such time as a replacement level probe is available for the butts.
Adjustment to the float switch shaft may be required to establish the appropriate "Butts full" level.
Clive, what you're available I'd appreciate your help to make this float switch more robust.
Penri
Float switch
Float switch
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- Float switch v0.1.odg
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Re: Float switch
Herewith an updated document covering the design of the float switch.
- Attachments
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- Float switch v02.odg
- (21.17 KiB) Downloaded 83 times
Re: Float switch
I'm approaching the end of the 1st off build for a combined minimum / maximum water level float switch. I want to integrate it into the same wiring as the existing device / cable assembly with has 3 usable wires available, Blue, Brown and Orange
The device uses 2 uswitches, one for max and other min., a diagram will be forthcoming shortly.
Operation will be:
water level < min. - us1 closed us2 open
min. < water level < max. - us1 closed us2 closed
max < water level - us1 open us2 open
Assuming that I connect one wire, the Blue one, to the Common of both uswitches, how would you like the other two wires connected on the uswitches ie the NO or NC terminals?
Hope that makes sense.
The device uses 2 uswitches, one for max and other min., a diagram will be forthcoming shortly.
Operation will be:
water level < min. - us1 closed us2 open
min. < water level < max. - us1 closed us2 closed
max < water level - us1 open us2 open
Assuming that I connect one wire, the Blue one, to the Common of both uswitches, how would you like the other two wires connected on the uswitches ie the NO or NC terminals?
Hope that makes sense.
Re: Float switch
Penri,
First of all, I've been struggling to get my head round the terms NO and NC in this context because, once installed, the 'Normal' condition isn't necessarily with the switch open. So having revealed my confusion, I will couch my request in terms related to the installed situation which might be considered normal.
Normally the Butts will be neither completely full nor completely empty. With the current installation, the contact that is designated NO is closed because the float is not floating. The wire from this contact is pulled up on the Veroboard, before being routed to a GPIO pin (see https://wmtprojectsforum.altervista.org ... ss_0.3.odt). This means that the input is low until the water reaches the float, eg Active-High.
I can see no reason to do anything different with the new 'Empty' Float Switch, so it makes sense from a logical point of view to keep the Active-High arrangement; the software will then do something when it sees a high regardless of which switch is being monitored. With the new switch the float will be floating in the 'Normal' condition, so to keep our Active-High state, I would suggest the the NC contact should be routed to the Interface where it can be pulled up and the high will occur when the butts are empty.
Have I got it the right way round?
This means that I'll need to prepare a 'Mod Kit' for the Sump, WButts and S Butts interfaces. This will consist of an additional green TB terminal (I think we'll have to have two), an additional pull-up resistor, an additional jumper from another 74HC4050 output and a bit of modding on the Veroboard. I will have to remove the Veroboard to do this and that's probably easier if the whole interface is removed to the Workshop (or here), so the whole operation is likely to take an hour or so.
First of all, I've been struggling to get my head round the terms NO and NC in this context because, once installed, the 'Normal' condition isn't necessarily with the switch open. So having revealed my confusion, I will couch my request in terms related to the installed situation which might be considered normal.
Normally the Butts will be neither completely full nor completely empty. With the current installation, the contact that is designated NO is closed because the float is not floating. The wire from this contact is pulled up on the Veroboard, before being routed to a GPIO pin (see https://wmtprojectsforum.altervista.org ... ss_0.3.odt). This means that the input is low until the water reaches the float, eg Active-High.
I can see no reason to do anything different with the new 'Empty' Float Switch, so it makes sense from a logical point of view to keep the Active-High arrangement; the software will then do something when it sees a high regardless of which switch is being monitored. With the new switch the float will be floating in the 'Normal' condition, so to keep our Active-High state, I would suggest the the NC contact should be routed to the Interface where it can be pulled up and the high will occur when the butts are empty.
Have I got it the right way round?
This means that I'll need to prepare a 'Mod Kit' for the Sump, WButts and S Butts interfaces. This will consist of an additional green TB terminal (I think we'll have to have two), an additional pull-up resistor, an additional jumper from another 74HC4050 output and a bit of modding on the Veroboard. I will have to remove the Veroboard to do this and that's probably easier if the whole interface is removed to the Workshop (or here), so the whole operation is likely to take an hour or so.
Terry
Re: Float switch
Terry, thank you.
I didn't realise there was a change required on the interface board when I made my suggestion of a min. level sensor, does the extra work required add enough value to the system operation to warrant it?
I didn't realise there was a change required on the interface board when I made my suggestion of a min. level sensor, does the extra work required add enough value to the system operation to warrant it?
Re: Float switch
I think it does, because we currently have insufficient information about the level of water in the Sump / Butts to make a decision about whether to pump water to or from them at start-up.
Currently, we have no idea if there is any water in the Butts or the Sump unless the system happens to startup when the water is at an x25 mm value. With the Empty switch we would at least know that there is some water in the butts and we could set it to show high until the water level is sufficient to pump (rather than actually empty). Perhaps we should call it the Low-Level Float Switch.
If we had a second sensor that gave a reading without requiring a change in water level to register, then we probably wouldn't need the 'Empty' switch, but if we did, we'd still have to modify the Interface to accommodate it.
Currently, we have no idea if there is any water in the Butts or the Sump unless the system happens to startup when the water is at an x25 mm value. With the Empty switch we would at least know that there is some water in the butts and we could set it to show high until the water level is sufficient to pump (rather than actually empty). Perhaps we should call it the Low-Level Float Switch.
If we had a second sensor that gave a reading without requiring a change in water level to register, then we probably wouldn't need the 'Empty' switch, but if we did, we'd still have to modify the Interface to accommodate it.
Terry
Re: Float switch
That's fine, I'll carry on with completing the 1st off "new" float.