B+K precision 2530B User manual

Model: 2530B, 2532B
Calibration and Adjustment Procedure
V111011

Revision History
Date
Edition
Revise Reason
Revise Content
Revised by
11.04.10
V1.0
None
None
Jason
11.10.11
V111011
Complete re-edit
All
Jeremy

Calibration Procedure
To calibrate the 2530B or 2532B Digital storage oscilloscope, user must first unlock access to calibration
menu.
How to Unlock Access to Calibration Menu
1. Unplug all attached inputs, power off the instrument, and restart.
2. Press UTILITY button.
3. Then, go to Page 2/4 and select “Do Self Cal” from the menu options. (You should have a black
screen with the phrase “Disconnect Everything from All Inputs” at the top)
4. Now do the following in order:
1. Press the CURSORS button once.
2. Press the DEFAULT SETUP button once.
3. Press the SET TO 50% button once.
4. Press the 5th menu selection button once (This is the button directly above the PRINT
button on the right side of the display)
5. Press the AUTO button once.
6. Press the FORCE button once.
5. If you follow the above steps correctly, you should be returned back to the main display with the
UTILITY menu opened. If not, repeat steps 2-4 again.
6. The instrument is now unlocked for access to the calibration menu. After re-adjustments are
complete, users will need to lock access to the calibration menu. Instructions to do this will be
shown at the end of this document.
After unlocking access to the calibration menu, the user must make note of the following FIRST before
continuing below to make the appropriate adjustments.
NOTE:
-The instrument MUST run (to warm up) for AT LEAST 15 minutes BEFORE any
adjustments are made.
-Power to the instrument must be connected at all times during the course of adjustments.
Voltage Adjustments
1. From your calibrator instrument, setup a 30 V DC signal and connect it to CH1 input of the
oscilloscope, then press AUTO button once. (This will automatically adjust and align the signal
on the display)
2. Press the UTILITY button, and go to Page 2/4 to select “Do Self Cal” from the menu options.
(You should have a black screen with the phrase “Disconnect Everything from All Inputs” at the
top)
3. Now, do the following in order:
1. Press CURSORS button once.
2. Press MEASURE button two times.
3. Press ACQUIRE button three times.
4. If you did it correctly, you will enter the calibration menu (shown below). If you did not, redo the
above steps again. Select “Volt Adj” from the soft menu to enter the voltage adjustment menu.

5. On the screen, the voltage scale should be at 10 V/div, timebase should be 2.50 ms, and you should
see a DC signal at 30 V. Change the timebase to 2.50 us. Make sure “Source” in the soft menu is
set to “CH1”. The display should look like below:
6. Make note of the measured “Mean” value. We will call this mean(+). (For positive DC)
7. Next, change the DC signal on the calibrator to –30 V.
8. Make note of the measured “Mean” value again. We will call this mean(-). (For negative DC)
9. Now, calculate and see if mean(+) – mean(-) = 60 V. If it is not equal, use the universal adjust
knob to either increase or decrease the value of “Range zoom”. Adjust until you get +30 V for
mean(+) and – 30V for mean(-) so that the difference will equal to 60 V. Refer to the two pictures
below for reference.
Figure 1 - +30 VDC mean(+)

Figure 2 - -30 VDC mean(-)
10. If you adjusted according to the above, you should be able to calculate the mean(+) – mean(-)
value to be 60 V (30 – (-30) = 60).
11. Once finished, turn the CH1 volt/div knob to set to 5.00 V scale. Keep timebase at 2.50 us.
Repeat steps 6-10, except with 15 V signal from the calibrator, adjust mean(+) to 15.00V and
mean (-) to –15.00 V to calculate the difference equal to 30 V.
12. Again, when finished repeat step 11 for each and all other vertical scale ranges accordingly listed
below with their corresponding settings:
Volt/div Scale
DC Signal
(Set on
Calibrator)(Positive
DC/Negative DC)
Mean(+)
Mean(-)
Mean
Difference
(Mean(+) – (Mean(-))
2.00 V
+6VDC/-6VDC
6.00 V
-6.00 V
12 V
1.00 V
+3VDC/-3VDC
3.00 V
-3.00 V
6 V
500 mV
+1.5VDC/-1.5VDC
1.50 V
-1.50 V
3 V
200 mV
+0.6VDC/-0.6VDC
600.0 mV
-600.0 mV
1.2 V
100 mV
+0.3VDC/-0.3VDC
300.0 mV
-300.0 mV
600 mV
50.0 mV
+0.15VDC/-0.15VDC
150.0 mV
-150.0 mV
300 mV
20.0 mV
+0.06VDC/-0.06VDC
60.00 mV
-60.00 mV
120 mV
10.0 mV
+0.03VDC/-0.03VDC
30.00 mV
-30.00 mV
60 mV
5.00 mV
+15mVDC/-15mVDC
15.00 mV
-15.00 mV
30 mV
2.00 mV
+6mVDC/-6mVDC
6.00 mV
-6.00 mV
12 mV
13. Once adjustments have been made for ALL of the vertical scale ranges, press the “SAVE” soft
button from the menu and all the adjustments will be stored into the instrument.
14. Now, repeat steps 1-13 for CH2 for re-adjustment.
15. After both channels are re-adjusted, the instrument needs to do a self calibration prior to use. To
do this, press UTILITY and go to Page 2/4 and select “Do Self Cal”. With nothing connected at
all the inputs (This is very important as it will affect calibration and all re-adjustments made prior
in above steps), press SINGLE button to begin self calibration. This process can take up to a few
minutes.
Note:
-Be sure to save before exiting calibration menu.
-Any key press not mentioned in the above instructions will exit the calibration menu without
saving any changes. Keep this in mind while making adjustments for each scale.

Trigger Adjustments
1. From the calibrator, setup a Sine signal with frequency of 200 Hz and amplitude of 3 Vpp. Make
sure there is 0 offset.
2. Input this signal into CH1 input and press AUTO button for automatic rescaling.
3. Press CH1 button and from the soft menu, select “Coupling” option to “AC”.
4. Press UTILITY button, then select “Do Self Cal” from Page 2/4.
5. With the black screen for self cal on display, do the following in order:
1. Press CURSORS button once.
2. Press MEASURE button two times.
3. Press ACQUIRE button three times.
6. If you did it correctly, you will enter the calibration menu (shown below). If you did not, redo the
above steps again.
7. Select “Trig Adj” from the soft menu to enter the trigger adjustment menu. There should be four
soft menu options: Source, Center, Delta, and Save.
8. Adjust the vertical and horizontal scale of the sine wave so that it fits about one and a half cycle of
the waveform (see below)
9. We will first adjust the trigger center. The trigger center is the point at which the signal is
triggered at the horizontal trigger marker, aligned with the trigger level as illustrated below:

10. Use the trigger LEVEL knob to find out the upper limit and lower limit of the trigger range. To do
this, turn the knob to increase the trigger level up until the signal is no longer triggered. This will
be the upper limit, so make note of the voltage of this level. Likewise, decrease the trigger level to
find the lower limit. Make note of the voltage of this level.
11. To determine the trigger center point, simply take the difference of the upper limit and lower limit,
then divide by 2. The result will be the current trigger center level.
12. If the result seems off from the actual signal (see image below), re-adjustments can be made in the
following steps.
13. Take the trigger center level from step 11 and turn the LEVEL knob until the trigger level is at the
same level.
14. Now, select “center” from the soft menu and use the universal knob to increase or decrease the
value until you catch the critical point between where the signal is triggered and not triggered.
You will know the signal is not triggered when the waveform starts moving across the screen and
not holding a steady sine wave.
15. Once finished, move the trigger level by turning the LEVEL knob to the opposite polarity of the
trigger center level calculated in step 11. Meaning, take the negative of that value and set the
trigger level to that value on screen. Observe to see whether the waveform is being triggered or
not. If not, repeat step 13-14 again. Follow the above steps for CH2 and do the same thing by
selecting “CH2” as “Source” from the soft menu.
Note: Increasing the “center” value will adjust the trigger center point upwards. Decreasing the
“center” value will adjust the trigger center point downwards.
16. Below is an example that follows the instruction steps 10-15 above.

Example:
oUpper limit trigger range = 3.12 V and lower limit trigger range = -7.04 V, as illustrated
below. When adjusted beyond these two points, signal is no longer triggered and will
move across the screen.
o(3.12V – (-7.04V) ) / 2 = 5.08 V. This will be the current trigger center level.
oTurn the LEVEL knob until trigger level is set to 5.08 V level. Select “center” and
increase the value until the critical point where the signal turns from untriggered to
triggered (see image below):

oTurn the LEVEL knob to -5.08 V now and make sure the waveform is still triggered (see
image below). If not, re-adjust the “center” value.
17. Now, we will adjust the trigger range. Select CH1 as “Source” in the soft menu.
18. The trigger range is the range that where signals will be triggered, as illustrated below.
19. Adjust the scale of the waveform so that there are a few cycles of the signal displayed.
20. Turn the LEVEL knob and observe the trigger range. If the trigger range exceeds the waveform
display range, meaning that the signal is still triggered when trigger level is beyond the waveform
display level, then the “delta” parameter in the soft menu needs to be adjusted.
21. Select “delta” and turn the universal knob to adjust the delta value that will change the trigger
range. Increasing the delta value will reduce or lower the trigger range. Decreasing delta value
will enlarge the trigger range. For example, below are two illustrations, one with the trigger range
too large and one with trigger range too small as indicated by the red lines.

22. Once finished, repeat and do the same (steps 19-21) for all other vertical scales (i.e. 10V/div,
5V/div,…,2mV/div). You may need to adjust the amplitude of the signal output from the
calibrator to scale the waveform to fit on screen.
23. After all the vertical scales have been adjusted, repeat all the steps for CH2. To do this, first
select “CH2” for “Source” from the soft menu.
24. After all adjustments are done for both CH1 and CH2, select “Save” from soft menu to save all
the adjustment parameters into the instrument.
25. After both channels are re-adjusted, the instrument needs to do a self calibration prior to use.
To do this, press UTILITY and go to Page 2/4 and select “Do Self Cal”. With nothing
connected at all the inputs (This is very important as it will affect calibration and all re-
adjustments made prior in above steps), press SINGLE button to begin self calibration. This
process can take up to a few minutes.
Note:
-Be sure to save before exiting calibration menu.
-Any key press not mentioned in the above instructions will exit the calibration menu without
saving any changes. Keep this in mind while making adjustments for each scale.
After all adjustments are made and instrument is calibrated, users must lock the calibration menu access
before proceeding. Follow the instructions in the following section for details.

How to Lock Access to Calibration Menu
Once all adjustments are made and self calibration is completed, the instrument must be set back to lock
access to the calibration menu. This will bring the instrument back to normal operation mode. Follow the
below instructions to do this.
1. Press UTILITY button.
2. Select “Do Self Cal” on Page 2/4 of the menu and you will see the black screen that prompts for
initiating self calibration.
3. At this time do the following in order:
1. Press DEFAULT SETUP button once.
2. Press SAVE/RECALL button two times.
3. Press the UTILITY button three times.
4. If this is done correctly, you should not be able to access the calibration menu by selecting
UTILITY button, select “Do Self Cal”, press CURSORS button once, MEASURE button twice,
ACQUIRE three times.