Tektronix PWS2185, Руководство пользователя

Страница: 27 / 31

Operating Basics
Con fi guring the Instrument for Your Application
The menu system includes settings like Max Volt that determines the maximum voltage output of the power supply and
settings, like Out Recall and Save Last , that determine how the instrument initializes itself on power-up.
This power supply features a constant voltage/constant current automatic crossover. This feature permits continuous
operation in the transition from constant-voltage mode to constant-current mode as the load changes. The intersection of
the constant-current and constant-voltage modes is called the crossover point.
For example, if the load is such that the power supply is operating in constant-voltage mode, the power supply provides
a regulated output voltage. The output voltage remains constant as the load increases until the preset current limit is
reached. Then the crossover occurs. At that point, the output current becomes constant and the output voltage drops in
proportion to further load increases.
Crossover is indicated by the front panel CC and CV messages. If the CV message appears, the instrument is operating in
constant-voltage mode. If the CC message appears, the instrument is operating in constant-current mode.
Crossover from the constant-current mode to the constant-voltage mode also occurs automatically in response to a decrease
in load. For example, suppose you are charging a 12 V battery. Initially, the open circuit voltage of the power supply is
preset for 13.8 V. A low-battery places a heavy load on the power supply, and it operates in constant-current mode. You
adjust the instrument to charge the battery at the rate of 1 A. As the battery becomes charged and its voltage approaches
13.8 V, the load decreases to the point where the battery no longer demands the full 1 A charging rate. The power supply
then crosses over to constant-voltage mode.
Initializing to the Default Setup
Use the default setup to get the power supply into a default initial state.
1. Remove all leads from the output connectors.
2. Turn on the power supply.
3. Push Menu to bring up the Reset System menu. This menu allows you to set the instrument to default settings.
4. Push Enter .
5. Push the up arrow button to select Yes and push Enter to enable the default settings.
The default settings are:
Output On/Off = OFF
V-Set = 1.000V
I-Set = 0.1000A
Max Volt Set = Off
Save Last = On
Out Recall = On
Key Beep = Off
PWS2185, PWS2323, PWS2326, and PWS2721 User Manual 11