Panametrics CTF878, Service Manual

Page: 13 / 67

Model CTF878 Service Manual 3
Chapter 1.
Figure 4: Signal Error Limits Option
1. The first prompt asks for the minimum error limit for the correlation signal-to-noise ratio (SNR) calculated by the
CTF878. The default value is 10. The E8: SNR error message appears if the SNR falls below the limit programmed
here.
IMPORTANT:
SNR
Min should be changed from factory default settings only if absolutely necessary. These settings
may be changed by qualified field service engineers, only.
To enter the minimum SNR:
a.
Press
[ENTER]
to open the text box.
b. Use the numeric keys to enter the desired value.
c. Press [ENTER] to confirm your entry.
d. Press the [

] or [

] key to move to the next limit.
2. The next prompt calls for the low and high velocity limits. The
E9: VELOCITY RANGE error message appears if the velocity falls outside these limits. Repeat Step 1 above to enter
the desired limits.
3. The next prompt asks for the acceleration limit for detecting erroneous velocity outputs. The E10: ACCELERATION
ERROR message appears if the velocity changes by more than this limit from one reading to the next.
a.
Press
[ENTER]
to open the text box.
b. Use the numeric keys to enter the acceleration limit.
c. Press [ENTER] to confirm your entry.
Note: In the velocity and acceleration boxes, if the CTF878 currently displays metric measurements, the F1 softkey
displays the word “English.” If it displays English measurements, the F1 softkey displays “Metric.” Press [F1] to
display the measurement in the alternate format.
4. The last four prompts ask for the minimum and maximum values in millivolts for the Carrier and DMod
categories.
IMPORTANT: Carrier and DMod should be changed from factory default settings only if absolutely necessary. These
settings may be changed by qualified field service engineers, only.
To change the Carrier and/or DMod settings:
a.
Press
[ENTER]
to open the text box.
b. Use the numeric keys to enter the desired voltage.
c. Press [ENTER] to confirm your entry.
Min Max
OK Cancel
SNR Min
–100 Velocity m/s 100
15 Acceleration m/s
75 Carrier mV 1200
75 DMod mV 1500
Signal Error Limits
10