low flow alarm

I need to find a way to alarm when a small piston type metering pump has zero flow. The gpm is around .01. My available card in a very full plc is a 120v input. I have found some switches but I think the pulsing will make the switch cycle. Does anyone have like equipment in there plant or any other ideas? I thought about capacitance sensor but the line never goes empty.
Thanks in advance
Sheirj

How far apart do you see the pulses?. You still may be able to use this switch you referred to.

Besides, on a PD pump why wait til the flow is Zero? Wouldn't you want to stop it before Zero?

Have you ever checked out the company by the name of Dwyer. They have all kinds stuff like that but I don't know if it will go that small.

Thanks for the replies.

Rube, I'm not a pump guy so maybe I didn't describe the pump properly but I understand what you mean. This pump is a metering pump so it's ok to let it go dry. The pulses are about three seconds apart. I'm just think the switch will pulse as well.
hipoint, I have checked out dwyer. I am thinking if I get one set low enough it won't cycle or maybe I can put a timer in the logic say switch off for 3sec then alarm.
Tark, That is what I think I will try is to put it into the feedline and put a timer in the logic.
Thanks, It will be next week or so before I get to it.

could always use a magneto flowmeter, it will give you pulses per barrel.

I used the same type of pump for vitamins..It's a stroking pump and gives low flow..i will check the name of the sensor we used..We programmed with a 5 second time delay..No pulse for over 5 seconds shut down and flash a light..

Will track the info down for you tommorow..

D