Tp1-Test Point 1 - Emerson Rosemount 8800D Series Reference Manual

Reference Manual
00809-0100-4004, Rev DC
5.3.3 TP1—Test point 1
TP1 is the vortex shedding signal after it has gone through the charge amplifier and low pass filter
stages and into the input of the sigma delta A-to-D converter ASIC in the electronics. The signal
strength at this point will be in the mV to Volt range.
TP1 is easily measured with standard equipment.
Figues 5-4, and
shows an ideal (clean) waveform. Please consult the factory if the waveform you detect is
not similar in principle to Figure 5-3.
Figure 5-3. Clean Signals
0
3.0 V
0
A. Vortex signal (TP1)
B. Trigger level
C. Shedding frequency output
Figure 5-4. Noisy Signals
0
3.0 V
0
A. Vortex signal (TP1)
B. Trigger level
C. Shedding frequency output
Troubleshooting
5-5 show waveforms that may cause the output to be inaccurate. Figure
A
B
C
A
B
C
Troubleshooting
May 2016
5-3
73