Calibration - TTI QL II Series Service Manual

Refer to the General section for dismantling instructions and safety precautions. Normal calibration
is done without opening the instrument.
Allow 10 minute warm-up before commencing calibration.
Refer to the User Manual for detailed operation of these power supplies.
Equipment Required
A 5.5 digit multimeter with better than 0.02% accuracy on dc volts and better than 0.12% accuracy
on dc current (to 5A); alternatively use a precision shunt for current measurement. An electronic
load set to approximately 2.7A or a 1.8

Calibration

To enter calibration press
been repaired, the default calibration values should be loaded first by pressing SHIFT #, 91.
Pressing ESCAPE at anytime will abort the calibration procedure and revert to the stored
calibration values.
Having entered calibration mode, follow the table below. To increment to the next step press OK.
The calibration must be done in sequence. At the end of calibration press OK to store the
calibration. The instrument automatically sets the range and settings at each step.
Use the spin-wheel to adjust calibration; holding down the JOG SET OFF key will give x100
increments to speed up calibration. Pressing SHIFT will show the calibration value.
On triple units calibrate both output 1 and output 2.
There are two internal adjustments which are factory set and will normally only require adjustment
if a component has been changed in the associated area. If this is so proceed as follows. VR1 and
VR2 are both located near the top of the control pcb. They are accessible from both sides of the
board. Turn them both fully clockwise as viewed from the component side, fully anti-clockwise as
viewed from the solderside. Adjustment is done with the output set to off. Connect an ammeter
across the output terminals and adjust VR1 for +1mA. Remove ammeter and connect voltmeter
and adjust for VR2 –10mV. (minus or negative 10mV).
Calibration steps 17 to 22 on output 1 are for the Auxiliary output.
Step/Range
1, 35V 3A
2, 35V 3A
3, 35V 3A
4, 35V 3A
5, 35V 3A
6, 35V 3A
7, 35V 3A
8, 35V 3A
9, 35V 500mA
10, 35V 500mA
11, 15V 5A
12, 15V 5A
13, 15V 5A
Continued....
10
SHIFT,
#, 99. If the instrument is a long way out of calibration or has
Settings
0.01V 3A 10mV ± 0.5mV
0.01V 3A 0.010V on display
35V 3A
35V 3A 35.000 on display
0.01V 3A 10mV ± 0.5mV
35V 3A
2V 0.001A 1mA ± 0.5mA
2V 0.001A 0.001 on display
2V 0.1mA 0.1mA ± 0.05mA
2V 0.1mA flashing 0.0/0.1 on display
2V 4A
2V 4A 4.000 on display
2V 4.1A 4.100 on display
Ω
15W resistor.
QL355
Adjust for:-
35V ± 0.5mV
35V ± 0.5mV
4A ± 0.5mA
Calibration
Load
DVM
DVM V readback zero
DVM
DVM V readback span
DVM
DVM
milli-ammeter
milli-ammeter A readback zero
milli-ammeter o/p mA offset
milli-ammeter mA readback zero
change load
ammeter
ammeter A readback span
ammeter A readback 13bit
Detail
o/p 0V
o/p V span
o/p 0V
o/p V span
o/p A offset
o/p A span