LabVIEW
NI VISA LabVIEW cannot control external pump
@Mohaimin_95 wrote:
Hello,
Did you manage to resolve this issue? I'm experiencing the same problem. I have a DB25 port on the back of my pump, which I'm converting to DB9 and then connecting to an NI RS232/USB serial interface. The pump powers on, but I'm unable to adjust the speed—it’s stuck on the priming speed.
Did you read the last two posts before yours? The DB25 is probably not a serial port as you thought but instead contains analog and digital signals to control the pump. Most serial ports on pumps are DB9 and many manufacturers make different models, some with and some without remote control options. And the remote control options vary from only digital IO to switch it on and off, to analog IO to control its pump speed and RS-232 or RS-485 to control it from a computer. Models without any remote control option are usually a few 100 bucks cheaper and each remote control opotion makes the device 200 or more bucks more expensive.
It could of course be a different model, but in this manual on page 3-23 it clearly documents that the DB25 is NOT a serial port! Page 4-2 shows the different connectors and the difference between a Style A device (only having the DB25 analog and digital remote control connector) and the Style B device with two additional DB9 connectors which are the serial port in and out for daisy chaining multiple pumps together. Some models also have an USB port but it is not really clear if that supports a virtual RS-232 port or uses a proprietary USB protocol.
As to the communication, the serial protocol is described from page 3-30 to 3-27. It's kind of involved because of the Linkable Protocol to allow controlling multiple devices over one single serial port through daisy chaining, but most of the difficulties are avoided when only controlling one device.
