Wiring Contact to Frequency Converter

[Alex426]

Hello,
I am wiring a contact from a pump to a frequency-to-analog converter and I am having trouble getting the converter to see the input from the contact. The contact from the pump will close every time the pump completes a stroke which at max frequency is about 3Hz. I have attached the schematics of pump contact and the wiring setup for the converter (Red Lion IFMA). I currently have the 10k Ohm resistor wired to the Common terminal of the converter but I am not getting input to register at the converter and I have to wonder if I am wiring the devices correctly.

Converter:

https://files.engineering.com/getfi...8-8c7f-a313350166ee&file=Converter_Wiring.PNG

Pump Contact:

https://files.engineering.com/getfi...293-aa89216ef3c2&file=Pump_Contact_Wiring.PNG

 

[xnuke]

Please share your schematic showing how you connected the two parts.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Alex426]

Sure thing.

https://files.engineering.com/getfi...2-7f3e-4f3b-9abe-dc647bf61dae&file=Wiring.PNG

 

[xnuke]

According to the circuits you've provided, the pump contact puts out a voltage. When the pump is not running, the output of its circuit is Vss. When the pump is running, the output is Vdd-0.4 V. It is not a simple contact as you have tried to use it in your schematic diagram. You probably need something to interpose between the two circuits, like a solid-state relay.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[itsmoked]

!!! What you've designed is a Machiavellian way to fry the pump contact.

You do not put a capacitor across contacts like that. Recall that a capacitor will instantly discharge when shorted in that manner by the switch. I'd suggest you remove the capacitor entirely.

And while you're at it if the INPUT accepts 12V remove the 1kΩ resistor on the INPUT and certainly remove the 10kΩ on the COM.

That should do it.



Keith Cress
kcress -

http://www.flaminsystems.com