Hola:
Quiero comprar un MIAC y pretendo usarlo midiendo temperatura con sondas PT100.
El problema que tengo es que al hacer el diagrama en Flowcode y asignar las entradas analógicas de 0 a 255 bits no se a que temperatura corresponden los Bits.
¿Como haceis para trabajar con sondas, ya que no creo que sea tan sencillo como enchufarla y listo?
Gracias
Un saludo
Usar Sondas de Temperatura
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arizawilmer
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Re: Usar Sondas de Temperatura
Hola. El procedimiento para interpretar las senales de un elemento RTD es mediante una ecuacion que las puedes encontrar aqui https://es.wikipedia.org/wiki/RTD .Lo que mides con el Miac o microcontrolador es la resistencia del sensor mediante undivisor de voltaje. con esa resistencia puedes calcular la temperatura. La funcion entre resistencia y temperatura no es lineal. depende de la apliacione hay oportunidades en las que solo se trabaja en ciertos rangos que son considerados lienales.
Re: Usar Sondas de Temperatura
Ok. Gracias Arizawilmer.
El problema que estoy teniendo es que no soy capaz de que los condicionales atiendan a las fórmulas que le indico.
Si tengo dos entradas digitales "A" y "B" genero un código con el condicional, diciendo que SI A>B me de salida por Q1 y no me funciona.
¿Porque sólo funcionan los condicionales directamente con números?
SI A=1 salida por Q1. Funciona perfectamente.
Gracias de nuevo.
El problema que estoy teniendo es que no soy capaz de que los condicionales atiendan a las fórmulas que le indico.
Si tengo dos entradas digitales "A" y "B" genero un código con el condicional, diciendo que SI A>B me de salida por Q1 y no me funciona.
¿Porque sólo funcionan los condicionales directamente con números?
SI A=1 salida por Q1. Funciona perfectamente.
Gracias de nuevo.
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arizawilmer
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Re: Usar Sondas de Temperatura
Hola....Una pregunta no te funciona sobre el modulo o desde el simulador no esta funcionando? Puedes colocar la parte del codigo con la que tienes problemas. acompañalo con una descripccion de la version de flowcode y tipo de controlador que estas usando. Creo saber donde esta tu problema pero una respuesta seria prematura.
Re: Usar Sondas de Temperatura
Ok.
Os lo mando.
Cuando subes las barras de desplazamiento de las entradas digitales es cuando no funciona
Os lo mando.
Cuando subes las barras de desplazamiento de las entradas digitales es cuando no funciona
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arizawilmer
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Re: Usar Sondas de Temperatura
Tu error esta en la configuracion del macro miac entrada analoga la tienes definida como digital. Siempre puedes ver el valor de las variables corriendo el programa step-by-step
The error in the code is in the macro miac, the analog input is established as digital input. You can check the values of the variables by running the flowchart step by step.
The error in the code is in the macro miac, the analog input is established as digital input. You can check the values of the variables by running the flowchart step by step.
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- Miac Comparison two analog inputs.
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Re: Usar Sondas de Temperatura
Vale Ok.
Ahora ya funciona. Estaba un poco liada con las entradas Digitales y Analogícas.
Tema aclarado.
Ahora bien.
Si conecto una sonda de temperatura, por ejemplo PT100. Esta da 100 ohmios a 0ºC.
¿Pero si la entrada anlogica varia entre 0 y 255 bites. Como hago para convertir esos ohmios en bites?
Ya se que soy un poco pesada pero esto me está costando entenderlo.
Gracias de nuevo
Ahora ya funciona. Estaba un poco liada con las entradas Digitales y Analogícas.
Tema aclarado.
Ahora bien.
Si conecto una sonda de temperatura, por ejemplo PT100. Esta da 100 ohmios a 0ºC.
¿Pero si la entrada anlogica varia entre 0 y 255 bites. Como hago para convertir esos ohmios en bites?
Ya se que soy un poco pesada pero esto me está costando entenderlo.
Gracias de nuevo
Re: Usar Sondas de Temperatura
¿No puede ser posible que nadie sepa como hay que hacer para conectarle una sonda y poder trabajar con los rangos de temperatura????
Tampoco creo que sea algo tan facil como enchufarle al MIAC una PT100 y funcione o una PT1000 y tambien funcione
¿Alguien me puede decir como tengo que hacer para trabajar con entradas analógicas?
Tampoco creo que sea algo tan facil como enchufarle al MIAC una PT100 y funcione o una PT1000 y tambien funcione
¿Alguien me puede decir como tengo que hacer para trabajar con entradas analógicas?
Re: Usar Sondas de Temperatura
INCREIBLE!!!!!
Casi 7000 visitas y nadie se digna a explicar nada.
Sin comentarios.....
Casi 7000 visitas y nadie se digna a explicar nada.
Sin comentarios.....
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dazz
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Re: Usar Sondas de Temperatura
HI
Ci possono essere stati 7.000 visite sul tuo thread, ma unfortunantely se nessuno ha usato la pt100 con Flowcode, nessuno saprà la risposta, ma un breve Google alzato questa pagina, http://openenergymonitor.org/emon/buildingblocks/rtd- temperatura-sensing, che fornisce un'interfaccia e un calcolo necessario per utilizzare con un uc, anche se la pagina è per un arduino, si può facilmente utilizzare il calcolo in Flowcode, Again unfortunantely non c'era molto di un diagramma di flusso inviato per consentire ad altri di tentare di aiutare. Siamo tutti molto impegnati e vi aiuteremo se possiamo, ma si deve aiutarci ad aiutarti inviando quante più informazioni possibile e includere un foglio, quindi se qualcuno può aiutare lo faranno, ma come ho detto prima, se nessuno ha utilizzato il dispositivo sua difficile aiutare
Un utente ha cercato di aiutare voi su questo thread e si poteva avere premuto il pulsante di grazie, come ti puntato nella direzione giusta
Saluti
Dazz
HI
There may have been 7000 views on your thread but unfortunantely if no one has used the pt100 with flowcode, no one will know the answer but a quick google turned up this page, http://openenergymonitor.org/emon/build ... re-sensing which gives an interface and a calculation needed to use with a uc, although the page is for an arduino ,you can easily use the calculation in flowcode, Again unfortunantely there was not much of a flowchart posted to enable others to try to help. We are all very busy and will help if we can but you have to help us to help you by posting as much info as you can and include a datasheet, then if someone can help they will, but as i said before if no one has used the device its difficult to help
One user has tried to help you on this thread and you could have pressed the thanks button as he pointed you in the correct direction
Regards
Dazz
Ci possono essere stati 7.000 visite sul tuo thread, ma unfortunantely se nessuno ha usato la pt100 con Flowcode, nessuno saprà la risposta, ma un breve Google alzato questa pagina, http://openenergymonitor.org/emon/buildingblocks/rtd- temperatura-sensing, che fornisce un'interfaccia e un calcolo necessario per utilizzare con un uc, anche se la pagina è per un arduino, si può facilmente utilizzare il calcolo in Flowcode, Again unfortunantely non c'era molto di un diagramma di flusso inviato per consentire ad altri di tentare di aiutare. Siamo tutti molto impegnati e vi aiuteremo se possiamo, ma si deve aiutarci ad aiutarti inviando quante più informazioni possibile e includere un foglio, quindi se qualcuno può aiutare lo faranno, ma come ho detto prima, se nessuno ha utilizzato il dispositivo sua difficile aiutare
Un utente ha cercato di aiutare voi su questo thread e si poteva avere premuto il pulsante di grazie, come ti puntato nella direzione giusta
Saluti
Dazz
HI
There may have been 7000 views on your thread but unfortunantely if no one has used the pt100 with flowcode, no one will know the answer but a quick google turned up this page, http://openenergymonitor.org/emon/build ... re-sensing which gives an interface and a calculation needed to use with a uc, although the page is for an arduino ,you can easily use the calculation in flowcode, Again unfortunantely there was not much of a flowchart posted to enable others to try to help. We are all very busy and will help if we can but you have to help us to help you by posting as much info as you can and include a datasheet, then if someone can help they will, but as i said before if no one has used the device its difficult to help
One user has tried to help you on this thread and you could have pressed the thanks button as he pointed you in the correct direction
Regards
Dazz
To sign up to the V5 forum follow this link http://www.matrixmultimedia.com/forum_upgrades.php
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arizawilmer
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Re: Usar Sondas de Temperatura
Us dazz write the thread had a lot of intros.( I'm going to answer in English if someone need more help in Spanish please write a comment with your question).
At the start i didn't answer because I was busy.
I'm going to divide the answer in multiple sections
First a PTC100 is a platinum RTD with a equation of:
R = R0* (1+alpha*Delta T) where alpha is 0.00385
A PTC is a resistor and to measure that resistance you have to apply a voltage ,but you have to limit the current with a resistance in series . I usually install a resistance of 100 ohms if you are using a PIC with a source of 5V and adc of 1024 bits
solving the equations for the resistance in series we have:
5*R/(100+R)=vm
vm is the voltage that the ADC converts
then
if we replace the PTC equation
500+500*alpha*delta(T)=200*vm+100*vm*alpha*delta(T)
delta(T)*(500*alpha-vm*100*alpha)=200*vm-500
delta(T)=(200*vm-500)/(500*alpha-vm*100*alpha) (1)
Now we have the temperature of the adc vs the temperature
if we apply
X1*5/1024=vm (2)
where X1 is the byte of 10 bits in decimal value
you can solve equation 1 and 2 and obtain the value of the temperature for any value of conversion from the ADC
if you are using standard electronic PTC the connection is like a resistor. If you are using a industrial version with four pins you connect a input resistance between e+ and a source e- to ground . S+ go to the adc and S- to digital ground ,you have to use a 10 or 100 Mega ohms resistance between ADC pin and digital ground to increase the impedance of the circuit.
Know if for your application if for a industrial enviroment you have to install a whetstone bridge and use a instrumentation OAMP
you can check wikipedia for the different configuration for each sensor the equation are similar in their solution to the more simple circuit
http://en.wikipedia.org/wiki/Resistance_thermometer
At the start i didn't answer because I was busy.
I'm going to divide the answer in multiple sections
First a PTC100 is a platinum RTD with a equation of:
R = R0* (1+alpha*Delta T) where alpha is 0.00385
A PTC is a resistor and to measure that resistance you have to apply a voltage ,but you have to limit the current with a resistance in series . I usually install a resistance of 100 ohms if you are using a PIC with a source of 5V and adc of 1024 bits
solving the equations for the resistance in series we have:
5*R/(100+R)=vm
vm is the voltage that the ADC converts
then
if we replace the PTC equation
500+500*alpha*delta(T)=200*vm+100*vm*alpha*delta(T)
delta(T)*(500*alpha-vm*100*alpha)=200*vm-500
delta(T)=(200*vm-500)/(500*alpha-vm*100*alpha) (1)
Now we have the temperature of the adc vs the temperature
if we apply
X1*5/1024=vm (2)
where X1 is the byte of 10 bits in decimal value
you can solve equation 1 and 2 and obtain the value of the temperature for any value of conversion from the ADC
if you are using standard electronic PTC the connection is like a resistor. If you are using a industrial version with four pins you connect a input resistance between e+ and a source e- to ground . S+ go to the adc and S- to digital ground ,you have to use a 10 or 100 Mega ohms resistance between ADC pin and digital ground to increase the impedance of the circuit.
Know if for your application if for a industrial enviroment you have to install a whetstone bridge and use a instrumentation OAMP
you can check wikipedia for the different configuration for each sensor the equation are similar in their solution to the more simple circuit
http://en.wikipedia.org/wiki/Resistance_thermometer