serial write and read only reads if command is written 3 times

[Yamaeda]

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@dugan wrote:

Ok, problem solved, but not in a satisfying way. I was trying to get the basic interface working on my laptop before transferring it over to the computer that will actually run the instrument, but when I tried running it off that computer, I don't run into the problem at all. The computer is running Windows 7 while the laptop is Windows 8, but I don't think that is the issue. More likely I would guess is that the laptop is running a 32-bit version of LabView on a 64-bit OS while the computer is running a 64-bit version of LabView on a 64-bit OS. Sorry I can't offer any better info, but at least my problem is solved.

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Are you using the internal serial ports or a USB-serial adapter? My guess it serial port/driver quality in this case. We had some instances where a device refused to talk to the internal port and required a dongle to have another one a month later working the other way around ...

/Y

[AnalogKid2DigitalMan]

Perhaps is has to do with the signal voltages of the RS-232 ports? RS-232 is a fairly loose standard.

-AK2DM

[dugan]

I doubt it's either of those things. I'm using the serial port of the instrument through a serial-to-USB adapter to interface with the computer. Neither a prolific nor FTDI chipset adapter worked on the Windows 8 laptop, but both worked on the Windows 7 desktop. Aside from OS and LabView/NI MAX version, everything was the same, so I don't think it was a cable/hardware issue.