Cheap & dirty sump Control
Cheap & dirty sump Control
(OP)
Anyone have a cheap solution to run a 15HP sump...
There is a 4-20mA signal availble to use for water level.
I just want to empty the hole when it gets full.
I was hoping there would be a relay that accepts 4-20mA and has a set of dry contacts.... If not could I put a resistor in and try to use the relays drop out/pick up voltage for the job?
Everyone here is talking about a small PLC but I think this is a waste of time...
Regards,
TULUM
There is a 4-20mA signal availble to use for water level.
I just want to empty the hole when it gets full.
I was hoping there would be a relay that accepts 4-20mA and has a set of dry contacts.... If not could I put a resistor in and try to use the relays drop out/pick up voltage for the job?
Everyone here is talking about a small PLC but I think this is a waste of time...
Regards,
TULUM





RE: Cheap & dirty sump Control
You could use a Newport meter with mA inputs and a relay contact or two. Set the limits to cut in the relay contacts at 4mA and out a 20mA. Done.
Steve
RE: Cheap & dirty sump Control
You might be able to do it with a tiny bit of thought and
something called a "latching" relay. This device is
"set" when you have the full limit switch activated. The
latch is "reset" when the empty condition is met.
I would suggest NOT going with a 4-20ma loop. Go with
simple dry contact level switches. Otherwise you get into
the area of voltage comparators, etc.
The set and reset were quoted as one can make a SR flip
flop (a very common type of electronic circuit). The
SR stands for, you guessed it, set/reset.....
Now, I would strongly suggest that you drive the sump pump
from a rather heavy duty activator/contactor and drive
the contactor with the latching relay. 15hp definitely is
in the range of rather heavy duty contacts. You might
take a look at an electric elevator catalog or supply
house for the components (other than the level switches)
for your efforts.
Hope that this helps.
Cheers,
Rich S.
RE: Cheap & dirty sump Control
I agree with Rich do not try to make a 4-20ma signal run any relay(directly) you will be sorry. Besides not working you may destroy the motor or the contactor.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Cheap & dirty sump Control
ht
RE: Cheap & dirty sump Control
http:/
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I don't suffer from insanity. I enjoy it...
RE: Cheap & dirty sump Control
http:/www.jraef.com
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Cheap & dirty sump Control
RE: Cheap & dirty sump Control
Goodafternoon,
The cheapest and easiest way is to use 2 fixed limit switches, a float ball mounted on a stem, and a ATL starter. The bottom limit switch closes when the float ball raises up due to an increase in level and provides power to the common side of both the top limit and the seal-in contact on the starter(the top limit and the seal-in contact are in parallel). The top limit will be closed by the float at the level you choose to start the pump and this in turn acts to seal-in the starter coil. The starter remains pulled in until the level drops low enough for the float to open the contacts of the bottom limit switch.
Bigbillnky,C.E.F.....(Chief Electrical Flunky)
RE: Cheap & dirty sump Control
RE: Cheap & dirty sump Control
The situation is that there is already a 4-20mA water level signal there... so I think I will look at the Action instruments as well as the Omron suggestions above...
I have also find a Zelio controller for less than $200can and it does indicating and everything..
See what everyone thinks....
Thanks again...
RE: Cheap & dirty sump Control
http://e
And here's another level control relay:
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I don't suffer from insanity. I enjoy it...
RE: Cheap & dirty sump Control
TULUM
RE: Cheap & dirty sump Control
Alarm cards are available - which take in 4-20mA DC signal - and generate dry-contacts corresponding to user-selectable values. You can use one such card to generate two contacts - one when the sump is, say, 20% full (i.e., around 7mADC) and another when thesump is, say, 85% full (i.e., about 18 mA DC). This will do your job.
I cannot remember an international manufacturer off-hand - except for Yokogawa (which is relatively expensive in India, where I live.
RE: Cheap & dirty sump Control