So I have finally started working on this project. I decided that it would be easier to start with some more simple devices before working on this. So I bought one of the syringe pumps, 24v power supply, max3232 TTL to RS232 converter, and Arduino Mega. I went ahead and wired everything up to see if I could get it communicating with the Arduino. I used the MultiSerialMega from the library to try it out. I am pretty sure I had everything hooked up properly, using pins 18 and 19 connected to the max3232 converter, then connected to the pump. According to the manual, there are four switches that can be set so that the default baud rate of 9600 is set for the pump, so I set those. I was not able to get communication working properly, as there is supposed to be a return value sent back after you send a command to the pump. I did recieve some random characters from the pump a few times. When I measured the voltage of Rx and TX at the device, the RX in was at 0, while TX out was -8v. I am assuming there is something wrong with the serial converter or maybe I need to recheck my wiring. Should I be able to measure the voltage after the converter and get between -6v and -15v?
This is from the manual.
Baud rate 1200, 2400, 4800, 9600, 19200, 38400 baud
Data bits 8
Parity none
Stop bits 1
Flow control None
Physical protocols RS485, RS232
Logical protocols DT, OEM
Here is the instruction manual for the Versa pump.
http://www.google.com/url?sa=t&rct=j&q=kloehn%20versa%20pump%203&source=web&cd=1&cad=rja&ved=0CC4QFjAA&url=http%3A%2F%2Fwww.firsttenangstroms.com%2Fpdfdocs%2FVersa3.pdf&ei=5UcCUs0yzOTgA8uagJAB&usg=AFQjCNGYIPPXYaptL-_kttGOxurhII5p8w&bvm=bv.50310824,d.dmg