Controlling flow of a piston pump in a sinusoidal manner

[pp14]

Hi,

I have a single displacement piston pump. I am able to establish communication with the pump using labview using an RS-232 connection. I need to control the flow of the pump in a sinusoidal manner. I tried writing a code in which I generated a sine wave and tried to feed the values to my pump. The response time of my pump is 500 ms (One stroke of miston takes 500 ms). The problem is my pump is just reading the value at 500 ms and it is not able to go to the next value. Please suggest some way I can do this. 

I have attached the VI I was working on. 

Thank you.

[JonP]

Hi PP,

I can't look at your VI because I have got LabVIEW 2013, not 2014. But I assume that you are correctly waiting at least 500mS between each transmission? Feel free to use "Save for previous version..." and post a 2013 version.

There are plenty of problems that could cause this apart from erroneous LabVIEW. Some suggestions:

1. Are you using the correct protocol for the pump messages? E.g. does the pump send something back after 500mS (a movement completed packet) and expect it to e acknowledged before it will accept the next packet?

2. Are you terminating the RS232 packet in the way the pump expects, e.g. with Carriage Return / Line Feed?

3. Are you scaling the sinusoidal data correctly to fit within the minimum and maximum values the pump accepts?

Jon