Controller Capabilities
The TL Series uses a precision digital sine wave generator to produce a low distortion output. Dual LCD readouts clearly display programmed settings for voltage, current limit and frequency. Load current is measured using true RMS sensing and can be displayed on the front panel as well. Adjusting voltage, frequency and current limit is accomplished using a set of digitally encoded rotary knobs. For ATE applications, both IEEE-488 and RS232C interfaces are available as an option.

Applications
The precise voltage regulation, low distortion and noise levels and wide frequency range of the TL Series, combined with its easy to use front panel, make it a great precision Lab AC source. Built in measurements may be added (option -OP1) to extend the units usefulness for design applications of AC powered products. Applications requiring high frequency output such as gyro's, sensors and variable frequency controllers can be tested and operated by a TL Series unit at up to 8000 Hz. Contact factory for higher frequency requirements.

The included PC control program (requires -OP1 option) supports transient generation to simulate real-world AC line conditions like brownouts, voltage sags, surges and frequency fluctuations.

Output Power
The 351TL AC power source is rated for 350 VA with an output voltage between 90 % and 100 % of range and a load power factor of 0.7 to reflect typical operating conditions. Maximum RMS current is 2.8 A in the 135 V range. The 251TL is rated for 250 VA with an output voltage between 78 % and 100 % of range and a load power factor of 0.7. It's maximum current is 2.0 A in the 135 V range.

Remote Control
The optional remote control interface allows complete control of all AC source functions and provides measurement data to the controller. This allows the TL Series AC sources to be used as a low cost AC test system. A Windows™ Graphical User Interface (GUI) program is included with the interface option. Automatic power cycling and transient generation is made possible with the use of this GUI program. The GUI output control, measurement and transient screens are shown here. For quality assurance applications, measured voltage, current and VA readings can be logged to disk for documentation and analysis purposes. All data recorded is time stamped to create a complete history of each test run.

Up to eight often-used front-panel setups can be stored in non-volatile memory for quick recall from the PC controller through the interface. If needed, the front panel can be locked out to prevent operator intervention during test runs.
The 251TL and 351TL offer additional features over the bus such as the ability to select the turn-on or turn-off phase angle of the output voltage. This capability, combined with the peak current measurement function, enables inrush current analysis of a unit under test.

AC Transient Generation
Transient programming is supported by the GUI program with user defined transient lists of up to 100 steps. Available transient functions are voltage step, voltage drop, voltage sweep, voltage surge/sag, frequency step, frequency sweep, frequency surge/sag as well as functions that combine both voltage and frequency changes.
The intuitive Windows™ interface greatly facilitates creating and storing often used transient programs. Transient programs can be recalled from disk and executed once, continuously or a specified number of times. Editing functions such as delete and insert make it easy to modify or expand existing programs. This capability makes it easy to evaluate products for immunity to common AC line disturbances such as brownouts, surges, swells, sags and frequency variations.

Extensive Transient Control¹
With the addition of the remote control interface option, TL Series units are capable of producing transients with a high degree of user programmability. Setting up transient programs is facilitated by a Windows™ Graphical User Interface program that allows amplitude, frequency and event duration to be programmed from a PC. Time resolution is 1 ms (0.001 sec) with a minimum time interval ranging from 1 to 40 ms, depending on the transient type. Maximum transient time intervals are 9999 seconds. Transient programming allows the eects of common line disturbances such as voltage surges, sags, drop-outs and frequency uctuations on the unit under test to be evaluated.

Precision Measurements
For bench or automated test equipment (ATE) applications, the TL
Series can be ordered with the -OP1 option, oering both IEEE-488 and
RS232C remote control interfaces as well as extended measurements.
These measurements are available from the front panel and over the
bus. The TL Series uses closed-case calibration for both output and
measurement calibration, lowering cost of ownership.

SCPI Protocol Programming Commands
All functions of the TL Series are programmable over the available
IEEE-488 or RS232C interface. For example, the following tasks can be
performed over the bus:
• Set voltage to any level
• Change frequency
• Generate voltage dropouts, sags or surges
• Measure TRMS current, peak current, crest factor, TRMS voltage,
true power, apparent power and power factor
• Recall eight complete instrument setups from non-volatile memory
• Adjust current limit value
• Lock the front panel to prevent operator interference
• Switch between high and low voltage range
• Drop output voltage at specic phase angles for specied durations

Application Software
Windows™ application software is included with the -OP1 option package.
This easy to use graphical interface program provides complete control over all instrument
functions using the RS232C or IEEE-488 interface. With enhanced capabilities such as output sequencing, data logging and transient generation, many applications can be addressed without the need to write software.

Note 1: Voltage drop out transients can be programmed at random phase angles or at 0, 90, 180 and 270 degrees.