Solenoids and Thermocouples
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I am brand new to this and just purchased my first BS2 board. I am
trying to control two solenoid valves, one from a thermocouple and
one from a potentiometer. Can anyone advise me on any literature
that could assist me in trying to achieve this project?
trying to control two solenoid valves, one from a thermocouple and
one from a potentiometer. Can anyone advise me on any literature
that could assist me in trying to achieve this project?
Comments
For the input side you may need an ADC so you can read different analog values
on the pot and the thermocouple...maybe RCTime will do what you need. If you
decided to get clever I guess you could make a voltage to frequency counter and
read that instead..but it's not exactly fun....
Then on the output side I'd say a MOSFET with internal diode would fill the bill
nicely. It can take the Amps you will need to run the Solenoid valves. Sure
you could use transistors and such....it's your call.
If you can give us a bit more on what your final project will do we might have
other ways of doing it. Electronics has many ways to do the same task....[noparse]:)[/noparse]
Tim
>>> hughgoodbody@y... 12/16/03 11:36AM >>>
I am brand new to this and just purchased my first BS2 board. I am
trying to control two solenoid valves, one from a thermocouple and
one from a potentiometer. Can anyone advise me on any literature
that could assist me in trying to achieve this project?
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> I am brand new to this and just purchased my first BS2 board. I am
> trying to control two solenoid valves, one from a thermocouple and
> one from a potentiometer. Can anyone advise me on any literature
> that could assist me in trying to achieve this project?
I have been using a transistor to control a 6V DC 5 Watt oxygen
solenoid using a 'ZTX689B'. The Parallax document that will help you
is:-
Stamp Application no. 6 (August '95)
Silicon Steroids for the Stamp.
Help Your Projects Heft Big Loads
Using Switching Transistors, by Scott Edwards
> You basically have two issues....input and output.
>
> For the input side you may need an ADC so you can read different
analog values on the pot and the thermocouple...maybe RCTime will do
what you need. If you decided to get clever I guess you could make a
voltage to frequency counter and read that instead..but it's not
exactly fun....
>
> Then on the output side I'd say a MOSFET with internal diode would
fill the bill nicely. It can take the Amps you will need to run the
Solenoid valves. Sure you could use transistors and such....it's
your call.
>
> If you can give us a bit more on what your final project will do we
might have other ways of doing it. Electronics has many ways to do
the same task....[noparse]:)[/noparse]
>
> Tim
That pretty much details it.
there is a section on Analogue to digital chips in the manual. so
that part is simple.
if you want to control the solenoid as a switch, ie: if the temp is
over x degrees, turn the solenoid on, under, turn it off, the just
review the stuff on lighting LEDs.
if you want to control near a setpoint, check the PID stuff in the
industrial section of the parallax site.
You can't 'ramp' a solenoid, but the PID stuff will detail how to
pulse near your setpoint so as not to overhshoot.
Dave
>
>
> >>> hughgoodbody@y... 12/16/03 11:36AM >>>
> I am brand new to this and just purchased my first BS2 board. I am
> trying to control two solenoid valves, one from a thermocouple and
> one from a potentiometer. Can anyone advise me on any literature
> that could assist me in trying to achieve this project?
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
www.parallax.com
ken
I am brand new to this and just purchased my first BS2 board. I am
trying to control two solenoid valves, one from a thermocouple and
one from a potentiometer. Can anyone advise me on any literature
that could assist me in trying to achieve this project?
[noparse][[/noparse]Non-text portions of this message have been removed]
> You basically have two issues....input and output.
>
> For the input side you may need an ADC so you can read different
analog values on the pot and the thermocouple...maybe RCTime will do
what you need. If you decided to get clever I guess you could make
a voltage to frequency counter and read that instead..but it's not
exactly fun....
>
> Then on the output side I'd say a MOSFET with internal diode would
fill the bill nicely. It can take the Amps you will need to run the
Solenoid valves. Sure you could use transistors and such....it's
your call.
>
> If you can give us a bit more on what your final project will do
we might have other ways of doing it. Electronics has many ways to
do the same task....[noparse]:)[/noparse]
>
> Tim
>
>
Thanks for the info. What I am attempting to do is make a control
system. I am using two proportional control solenoid valves to
control the flow of two different fluids. One solenoid is controlled
via the potentiometer and the solenoid opens in proportional to the
pot. The other solenoid is controlled via a thermocouple and
controls the flow of the fluid in relation to the temperature of the
fluid.
> Thanks for the info. What I am attempting to do is make a control
> system. I am using two proportional control solenoid valves to
> control the flow of two different fluids. One solenoid is
controlled
> via the potentiometer and the solenoid opens in proportional to the
> pot. The other solenoid is controlled via a thermocouple and
> controls the flow of the fluid in relation to the temperature of
the
> fluid.
I tend to think of solenoids as On/OFF devices.
if you are trying to use them as proportional devices, the term
actuator comes to mind as a device name.
If it does open about 50% with a 2.5 volt signal and 100% with a 5V
signal, then read up on PWM.
That will output a linear signal, 0 to 5V for control. needs an R/C
and an op-amp to take the pulses into a smooth output.
Not sure how it would work directly into an L/C (the coil is an
inductor ) device without the op-amp.
Dave