Controlling proportional valve by using XBee PWM signal

[Eng.Hassan]

Hello everyone,

I'm working on a project to build a wireless control network. I will be using XBee S1 for the wireless network solution. I have set everything with no issues so far, however, I have only one issue with driving a proportional solenoid valve from the XBee PWM which operates at 3.3Vdc. I would like to control the valve which has 24Vdc power voltage and control signal of 0-10v.

I have looked at so many websites but unfortunately with no luck. I need to know what exactly the circuit that is required to overcome this matter.

The valve will be externally powered and the XBee pwm signal will provide the control signal that will represent the valve's opening and closing which has the voltage range of 0-10v

I really appreciate any kind of support and help!

Thanks

 

[chuckey]

So you want to convert your XBee S1 PWM to 0-10V? Do you know the current the control terminal takes? and the PWM carrier frequency?
Frank

 

[Eng.Hassan]

So you want to convert your XBee S1 PWM to 0-10V? Do you know the current the control terminal takes? and the PWM carrier frequency?
Frank

Thank you Frank, it says the Xbee PWM frequency is 15.6kHz , and for current, the datasheet says if you use 24 voltage supply without signal converter it takes from 300mA to 600mA , but in my case I will be using signal converter 0-10v , I don't if the current values remain the same.

Thanks again Frank..

 

[FvM]

The question was about the input current of the 0-10V control input. It can be expected to be high impedance, but is surely specified in the datasheet.

 

[Eng.Hassan]

hi guys, I just got the datasheet and it says the current for the output voltage 0-10Vdc is 0-20mA and Maximum current is 100mA. I need to know what exactly the circuit will look like as I almost fed up with all the design I have done and simulated on Multisim trying to get the design working. Here is an attachment of my best circuit design and it works but I'm not sure if it is applicable and will not cause any issues.

 

[FvM]

hi guys, I just got the datasheet and it says the current for the output voltage 0-10Vdc is 0-20mA and Maximum current is 100mA.

Makes no sense, actually. 0-20 mA can be if the control input is designed to work also for a current loop signal without modifications (500 ohm shunt). But what is 100 mA?

I don't believe that your circuit works. You'll want a linear voltage buffer after the low-pass. The 200 ohm, 30 nF low-pass has a cut-off frequency of about 26 kHz, it will not filter the PWM. 200 ohm is probably too much of load for the processor output.

 

[Eng.Hassan]

Dear FvM, I agree with you the cut off freq was completely ignored from me, I think the 200 ohm will be 1k ohm and 1uF will be for the capacitor. However, I don't believe I need the transistor as what I need is amplification instead but I couldn't figure out the circuit that works in my case. I just want a voltage output from 0-10v where 0% duty cycle represents 0v and 50% => 5v and %100 => 10v to control proportionally the valve opening and closing.

Thank yo very much for your help