Controlling syringe pump (Harvard Apparatus 33), commands not working

[lisa_elektrofi]

Hi all, 

I'm trying to control a Harvard Apparatus 33 pump with a cRIO 9063. A pdf for the pump's manual is here. Right now I'm having trouble getting the pump to listen to most of the commands. 

In my setup, I'm using a 6p6c cord to DB9 connector to connect to the DB9 port on the cRIO. I've checked that the baud rate is 9600 in the code and on the pump. The pump's address is 0. 

The VI attached is something I made to test out writing commands. The pump has responded correctly for the <cr> command. The pump stops running, and the remote LED comes on, indicating that the command was received. So I believe my cabling is good. However, if I try any other command, the pump doesn't respond. Part of me thought that I got the syntax for the command wrong, so I tried many different versions:

• RUN<cr>
• 0RUN<cr>
• 0 RUN <cr>
• 0,RUN,<cr> 

At this point, I'm at a loss for what it could be. I'm getting in touch with Harvard Apparatus to see if I'm missing anything obvious. But while I'm waiting, do any of you have prior experience or suggestions I could look into? Let me know if I should supply more info. 

Thanks!

[Albert.Geven]

two remarks.

1) You request only one character to receive. Why not more? 

2) You also open the visa session after you already set the serial parameters, this is not needed, but I don't know if it hurts. So just remove that call. Inside the seril sessions the resource is already opened.

I played with Harvard pumps long ago.

I also suggest to download the driver from NI's driver pages and look at those but none available for the 33

[lisa_elektrofi]

1) In an earlier version, I requested 8 characters, but wasn't receiving anything. I lowered it to 1 just to see if I could get anything. In any case, it seems like the pump doesn't receive the command, since it's not responding to any of the commands I write. (Except for the one command, which is a carriage return, which is like an emergency stop.)

2) Good point, I'll remove one of them. The problem still remains though. 😞

I'll look at drivers for their other pumps. I had searched earlier, and didn't find any drivers for the 33, but didn't think to look at other drivers. Thanks!

In the meanwhile, if there are more suggestions, please send them my way!

[lisa_elektrofi · Accepted solution]

Found the error - it was that "2" has to be wired into the "stop bits" input of setting up the serial connection. 

[Albert.Geven]

Congratulations. So it is just the speed between the chars that was hurting the communication.

[MartinP]

Lisa

Care to share your library for the pump, it seems I have to talk with it also ?

Martin