AnsweredAssumed Answered

8757 analyzer display gets trashed

Question asked by eda on Dec 7, 2007
Hi

I'm having a problem with an 8757. I have programmed a timed loop to access the 8757 and output the cursor value to me. thisis a power monitoring method that loops every second and executes the following code in the timer loop, where

Send8757String is a function that outputs cmd to the 8757 over gpib

cmd:='FD0;C1;OC';     //read op power
If Not Send8757String (Cmd,1) then Exit;
displayOpPower.Caption:=Copy (Cmd,1,6);  //extract the ampl data from the response
                     
cmd:='FD0;C2;OC';   //read input power
If Not Send8757String (Cmd,1) then Exit;

after several executions of this loop, like at least 10-20, suddenly the cursor information display on the 8757 becomes scattered across the display, some of it appearing at the bottom right of the display and off screen. Also a vertical line appears on the 8757 display in the upper right side.

Executing this loop through my debugger never reveals the problem. it only happens after i let it free run for, like i said, 10-20 iterations when suddenly the 8757 display starts to look garbled as mentioned.  Loop iteration is 1000 ms.

Is this a known one? Is there a fix or some problem with the code i'm sending? 

The code seems to work fine and returns the proper data regardless of the trashed 8757 display

thanks for any input

Ed.  

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