Tektronix TDS754 Driver problem?

[Face]

I download the TDS7XX driver from NI.com.
When I used the TDS7XX Gettiing Started.vi, one of my TDS754 oscilloscope work well under this vi.
But the other TDS754 oscilloscope sometimes can work,
but usually a timeout error will be displayed
oxBFFF0015 timeout before operaiton complete.
the error explain said: "visa wait on events sync.vi" time out.

Actually, in the TDS7XX Getting Started.vi, there are two place which use the " VISA wait on events sync.vi"
The first place will past this, but the second place can not pass. The GPIB cable are good. Both are worked under the same GPIB board.
THanks

[Ray K]

It is not clear from your email if you are using TDS754C or TDS754D. (They have different drivers.) But I'm guessing you're using the 754C. Is that correct?

Try increasing the timeout for the wait on event. That timeout is separate from the global timeout. One of your instruments may be slower than the other.

[Face]

I use TDS754D. Although it has different with TDS754D. but they do have the same instrument instructions.

It was weird that after I changed the primary address of that oscilloscope, this problem was solved.
can you help me to explain?
thanks

[Ray K]

Another instrument on your bus could have been using the same primary address and they could have been conflicting. It also could have been loose cabling, and when you changed your primary address you may have moved the instrument and shifted the cable.