08-21-2019 01:19 PM
Objective is to display the Pressure Dynamic curve (P vs t) with respect time using USB 232
I have pressure transmitter which show the pressure(Backside Transmitter Connection)
USB-232 is connected to the PC port
Questions:
A. I was reading Chapter on Control of Stand alone Instrument from Lab-view book. The chapter require to have GPIB interface bus.This required NI-GPIB device connected to the computer. In my case, I am just using USB-232 to the computer port? Is it correct way or do I need aforementioned device or DAC to read my transmitter data?
B. I use MAX to check if my USB-232 deice is connected properly to my computer. I have no issue in that but The Measurement and Automation Explorer gets different Visa resource names every time I unplugged the USB-232 port and reconnect back to PC port it show with ASRL21:INSTR, if I reconnect then again it shows ASRL24:INSTR the numbers keep getting bigger.? Why this happen Is there any issue with my Window or Is it normal?
C. I tried to create the block diagram it shows the following error? I didnt understand it clearly.
D. I tried to create the block diagram without the loops it shows the following error? I didnt understand it clearly.
They both show the Same ERROR.
Any advice How can I run my block diagram?
I have enclosed the VI file with this
08-21-2019 01:34 PM
Hi skdubey,
It's a little odd that the com port is being renamed each time, that might be an issue with the converter you're using, in any event, in my humble opinion, you're on exactly the right path at steps C and D. The next thing I would recommend is wiring constants or controls to the settings for Baud Rate, Parity Bits, ect. on the block diagram of your "Pressure trans" vi. The settings for these should be provided in the device documentation and might be different than the defaults. Some devices stream serial data constantly while others need a command written to them before they'll respond with anything, I would also look into that if you haven't already. Best of Luck!
08-21-2019 01:46 PM
Hi skdubey,
A. Is there a reference to this chapter available somewhere in the net?
B. Windows issue…
C. Your device does not send any (or: enough) data…
D. "Without loops" is ok when you wan to read just one message from your device. Any other use case requires loops…
Any advice How can I run my block diagram?
Read the manual of your device!
It should contain a chapter on "Remote control" or "communication" and also explain how to achieve communication between PC and device…
08-21-2019 02:07 PM
Windows will assign a new port number when disconnect reconnect if it can see the serial number of the device is the same as previously noted.
I would check I have the most up to date driver for the USB-Serial widget.
Ben
08-21-2019 02:16 PM
I try really hard to avoid USB-Serial converters with Prolific chipsets, I have had much better luck with FTDI-based devices. Usually I get the same Com Port# as long as I plug into the same USB port, and if that is a problem, it is easy to setup the FTDI driver to map the com port based on the serial #, regardless of location.
I would be surprised if your device simply wrote data blindly over the serial port, you almost certainly need to send a command and then read the reply to that command.
I usually test this kind of device in the following order:
08-21-2019 03:05 PM
In your first window above, it has Port Settings for this device listed TWICE. What does the other Port Setting show? Not sure about the current MAX software, but previously, it would ask whether it is to be controlled by VISA or Windows with a radial button in the Port settings. I always needed to select VISA in order to control it through LabVIEW.
08-23-2019 09:28 AM - edited 08-23-2019 09:42 AM
Hey,
I made following correction: But I am getting the error: