Panametrics CTF878, Service Manual

Page: 34 / 67

Chapter 3.
24 Model CTF878 Service Manual
3.1.5 Testing and Calibrating Digital Outputs
The Calibration/Test option can be used to test and calibrate (verify the accuracy of) the digital outputs. To enter the
option, scroll to the Digital Outputs option under the Calibrate/Test Menu and press [ENTER] . The screen appears
similar to Figure 24 on page 20.
3.1.5.1 Testing Digital Outputs
To test a Digital Output, you must connect a frequency counter to the digital output. Proceeding as above, select the
option for the Digital Output to be tested, and press [ ENTER ]. A clock appears in the middle of the screen with the
message “ TESTING IO” below it while the frequency counter is displaying the test frequency output. The test
frequency output should be a sweep from the low point to the high point. When the test is complete, the screen
returns to Operate Mode.
Repeat the process to test additional Digital Outputs.
3.1.5.2 Calibrating (verifying the accuracy of) Digital Outputs
To verify the accuracy of a Digital Output, you must connect a frequency counter to the digital output. Proceeding as
above, select the desired option for the Digital Output to be verified, and press [ ENTER ]. The screen appears as in
Figure 28 below. Step through options using the arrow keys.
Figure 28: Calibrate Digital Outputs Window
To verify the accuracy of a digital output using the frequency, follow these instructions:
1. The first prompt asks you to enter the frequency.
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.
2. Press the [

] arrow key to move to the SET box, and then press [ENTER] to set the frequency value entered.
3. Compare the value entered with the reading on the frequency counter. They should be very close (within ±1 Hz for
frequencies below 1 KHz).
To verify the accuracy of the digital output using the totalizer, follow these instructions:
4. The next prompt asks you to enter the total number of pulses.
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.
5. Press the [

] arrow key to move to the SET box, and then press [ENTER] to set the number of pulses.
6. Compare the value entered with the reading on the frequency counter. They should be very close (within ±1 Hz for
frequencies below 1 KHz).
Calibrate Analog Input
4
Exit
Hz Freq
Total 50 Pulses
SET
SET
Totalizer/Frequency 3:0
1000