Quote Originally Posted by 1113562 View Post
Bill, I have not tried the Hyperterminal test yet or tried adding another pulse to the code. I have not had time yet to try another vernier type either but i did try the simple comms port diagnostic test you describe. When you hold the zero button it stops the clock and the VB app clears the vernier off the display window, Y in my case. On releasing the zero button the Y display returns. The clock and data line LEDs to the vernier flash in a sequence, the vernier display zeroes but in general it leaves it in th H (hold) mode, never in the F.T Fast Read mode. Sometimes the clock and data pulsing sequence repeats a few times till it settles down to the Hold mode. Sometimes it leaves the vernier in the slow mode but this is rare.

I must try and test the other Vernier I have and give an update before trying the other tests.

Cheers.
Update: I Tried the other vernier which was very recently bought from Aldi but this just caused the PC VB6 App to go nuts with overflows and crash. This vernier is quite different from the older one I fist tried in that the interface pulsing on the clock and data lines at connection detect do not appear to change the setting modes at all on the vernier. Also when you push and hold the zero button on the vernier it just pulses the clock line for about 1/2 second it doesn't hold it off continuously while the button is depressed.

I then tried using hyperterminal with the older BCD type vernier as per the diagnostics tests recommended but this was not good. When the vernier I/F is plugged into the PC COM1 port hyperternial complains it cant open the com port. I think I am correct in setting HT to 'no flow control'? I did try 'hardware control' mode but that suffered the same fate. I thought then that I did have a wiring problem either in my serial link cable or the I/F driver circuit but I checked both and they seem to be correct to drawing - strange.

I'm not sure what to try next!!!

Cheers - John