help with labview/arduino mega to drive atlas scientific ezo perastaltic pump

[jacksy86]

Hi, could anyone give me some pointers please, as im doing a project at the moment where im reading PH levels and adjusting the level as necessary with two ezo perastaltic pumps which i bought from atlas scientific. 

I am reading the PH through an analog input which is working fine but for whatever reason i cannot get the pumps to drive. they are connected through uart protocol and im using tx/rx pins on the arduino mega. the pump seems to be getting the 5v input but does nothing with it. 

Im not sure if its the way im entering the string command or if this will just basically not work through labview.  see attached is my VI for running one of the pumps. both pumps will never be on together so it shouldnt be a question of power consumption. the pumps have a separate constant 12v supply and its just the logic that requires the 5v.  

Also see attached data sheet for pump.

https://atlas-scientific.com/files/EZO_PMP_Datasheet.pdf 

[StevenD · Accepted solution]

<cr> means carriage return (ascii 0xD). Concat your message with the carriage return constant from the string palette, or convert the string to \ code display and add \r at the end.

[jacksy86]

Steven i converted the string to \ code display and added the \r to the end of my string commands and this has worked a treat.

Thankyou you.

[jacksy86]

Hi, i wonder if you could help me? following on from the last problem i converted the function of the string command and it worked fine for a while. but now for some reason the pumps will not run even though nothing has changed. they just sit there flashing red to indicate that the command is not understood. i have tried the command every which way i can think of to try and get it to work but nothing. I have tried different UART channels on the arduino board and even tried a different board. this is a project for college that i have to a presentation on and im completely stressing at the moment which is probably not helping. but any advice would be welcome.  

[rolfk]

Your request contains no helpful information to help you. All you say is that it does not work and that you have tried many things. With that much information the only advice we can give you is, that there must be something you are doing wrong and you have to find out what it is.

My high level guess after looking in my magical crystal ball? Reread the previous messages, notice the little tidbit about

enabling "'\' Display mode" on the string control or constant and entering \r at the end!

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Try to process every single part of this sentence and check again in your program that it ALL is correct. If you are at it, right click on that constant or control and also enable "Visible Items->Display Style" and check the little glyph on the left hand side of your control or constant to display this '\' character.