Panametrics CTF878, Service Manual

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Model CTF878 Service Manual 33
Chapter 4.
4.1.3 Displaying Diagnostic Parameters
As part of its measurement menu, the CTF878 offers a list of diagnostic parameters to aid in troubleshooting in the
event of flowcell, transducer, or electrical problems. You can select any diagnostic parameter for display as a
measurement (see
Displaying and Configuring Data, Chapter 2 of the Programming Manual or Chapter 4 of the
Startup Guide). Table 4 below shows all the available diagnostic parameters and ranges.
Diagnostic
Parameter Displays Good Bad
Carrier
Amplitude
Up
The peak voltage amplitude (millivolts) of the
upstream channel received signal before
demodulation.
75–1100mV < 75mV or
> 1100mV
Carrier
Amplitude
Dn
The peak voltage amplitude (millivolts) of the
downstream channel received signal before
demodulation.
75–1100mV < 75mV or
> 1100mV
Carrier Gain
Up
The gain of the variable stage of the upstream
channel received signal.
–6 to +31dB ---
Carrier Gain
Dn
The gain of the variable stage of the
downstream channel received signal. –6 to +31dB ---
I Amplitude
Up
The RMS voltage amplitude (millivolts) of the
upstream channel demodulated signal I*.
295–1180mV
< 295mV or
> 1180mV
I Amplitude
Dn
The RMS voltage amplitude (millivolts) of the
downstream channel demodulated signal I*.
295–1180mV
< 295mV or
> 1180mV
Q Amplitude
Up
The RMS voltage amplitude (millivolts) of the
upstream channel demodulated signal Q*.
295–1180mV
< 295mV or
> 1180mV
Q Amplitude
Dn
The RMS voltage amplitude (millivolts) of the
downstream channel demodulated signal Q*. 295–1180mV
< 295mV or
> 1180mV
Modulation
Gain Up
The gain of the variable stage of the upstream
channel demodulated signals I and Q*.
–16 to +31dB ---
Modulation
Gain Dn
The gain of the variable stage of downstream
channel demodulated signals I and Q*.
–16 to +31dB ---
Tau
The time it takes for fluids to move from the
upstream channel to the downstream
channel.
N/A N/A
Correlation
SNR
The Correlation Signal–to–Noise Ratio. > 10 < 10
* Signals I and Q are those modulated carrier waves which have been converted (demodulated)
into a current equivalent to the original signal.