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Ensure Quality Battery Tests Using AMETEK VTI Instruments’ EX1401

Written on June 15, 2018 at 11:48 am, by

The EX1401’s accuracy, isolation, and sampling rate make it an ideal choice for battery testing.

Today, advanced batteries are widely used in transportation, commercial industries, aerospace, and defense industries, as well as in portable electronic devices. They must be tested with high accuracy to ensure they operate properly. To perform these tests, some companies are using the AMETEK VTI Instruments EX1401 Isolated Thermocouple and Voltage Measurement Instrument. The EX1401’s accuracy, isolation, and sampling rate make it an ideal choice for battery testing.

Isolation protects against common mode voltages

To increase battery life-cycle test throughput, multiple cells are connected in series during the charge and discharge cycles, and during the test, a voltage DAQ instrument measures the voltage across each battery. This process can create a high common mode voltage, and this voltage, combined with common mode noise, can cause the acquired data to become unreliable. Because the common mode voltage is high relative to the actual voltage of the batteries, it is difficult to distinguish between the noise and the actual battery voltage.

The EX1401 Isolated Thermocouple and Voltage Measurement Instrument provides up to 500V of channel- to-ground isolation in order to safeguard against high common mode noise. Each individual channel of the EX1401 is isolated and has exceptional input protection across a wide range of operating conditions. Not only does this ensure accurate measurements, it protects the instrument from harmful voltages.

High samples rates and temperature measurements

Slew rate is one of the most important performance specifications. To measure the slew rate, batteries under test are charged and discharged repeatedly while a voltage DAQ instrument measures the battery voltage. Using this data, engineers plot the battery discharge curve and calculate the expected battery life and number of charge/discharge cycles.

To create an accurate battery discharge curve, a battery test must measure battery voltage data at a high sample rate (at least 1 kSa/s) over a long period of time. In addition to measuring the battery voltage, the test must monitor the battery temperature to ensure the batteries do not overheat and cause damage when discharged quickly. Because temperature instruments generally do not support high voltage ranges and high sampling speed, however, voltage and temperature instruments generally have to be set up separately.

The EX1401 supports sampling rates up to 20 kSa/s, so capturing the voltage changes every millisecond is easy, and the batteries’ slew rates can be calculated accurately. Each channel of the EX1401 is independent and software configurable. Each of the 16 channels can be configured to measure voltage on different ranges or temperature independently. It allows the engineer to use the same instrument to measure both required measurement types. As a result, it can increase the flexibility of the test, reduce the total cost of ownership of the whole system and save storage space. Furthermore, each channel is equipped with an individual 24-bit ADC. During the data acquisition process, data from all channels are synchronized. The EX1401 allows the engineer to connect and test multiple batteries at the same time, increasing the test throughput.

Free, turn-key software aids analysis

To analyze the data, AMETEK VTI Instruments supplies EXLab Express, a free, turn-key software package. EXLab Express provides a Microsoft® Excel-like channel configuration table that allows users to easily configure channels for voltage and temperature measurements. Once the channels are set up and the data acquisition process begins, the data can be monitored in various intuitive ways. Once a test is complete, users can play back the data using EXLab Express or export the data to another software package for further data analysis.

When combined with EXLab Express software, the EX1401 offers everything needed for battery testing. It provides 500V isolation to safeguard against common mode noise. It supports sampling rates up to 20 kSa/s to capture batteries’ voltage changes on the millisecond level. It is also a flexible instrument that supports 16 software-configurable voltage and temperature channels, increasing the flexibility and throughput of battery testing, as well as decreasing total cost and storage requirements.

MIL-HDBKs, MIL-STD-704 Guide Avionics Power Testing

Written on May 24, 2018 at 11:03 am, by

By Jon Semancik, Director of Marketing, AMETEK/VTI Instruments 

Aircraft electronics and other electrically-powered equipment must be tested under extreme power conditions to ensure it will operate reliably once in the air. In the military world, MIL-STD-704 (now up to rev. F), ‘Aircraft Electric Power Characteristics’, establishes the requirements and characteristics of aircraft electric power.

The standard is not only used by the US military and military contractors, but has also been adopted, either directly or indirectly, worldwide. For example, the Chinese standard, GJB 181, ‘Characteristics of aircraft electrical power supplies and requirements for utilization equipment,’ is largely based on MIL-STD-704.

MIL-STD-704 actually defines the power characteristics of an aircraft electric power system, not the test requirements. For guidance on testing, there is a series of eight handbooks that specifies tests for different types of input power, titled MIL-HDBK-704. These guidance documents, including MIL-STD-704 (revisions A through F) are available online at EverySpec.Com.

The tests specified in the MIL-HDBKs is designed to ensure that airborne utilization equipment, which is defined as equipment that receives power from the aircraft’s electric power system, is compatible with the power system. To run these tests, a sophisticated power source is essential to simulate various power conditions. In addition, you also need whatever equipment is required to monitor the unit under test (UUT) while running the test.

AMETEK Programmable Power has provided test equipment for compliance tests for airborne utilization equipment for decades. Its test equipment systems cover the latest versions of MIL-STD-704 to make it more effective and easier to use. Its MIL-STD-704 test solutions are in use by customers in the USA and all over the world.

MIL-HDBK-704-1 through MIL-HDBK-704-8 specify the acronyms used for the seven power groups. These are:

  • SAC (single phase 115V/400Hz)
  • TAC (three phase 115V/400Hz)
  • SVF (single phase 115V various frequency)
  • TVF (three phase 115V various frequency)
  • SXF (single phase 115V/60Hz)
  • HDC (270V DC)
  • LDC (28V DC).

MIL-HDBK-704-3 specifies AC tests

As an example, let’s look at the tests specified by MIL-HDBK-704-3. This document provides guidance for testing utilization equipment that requires three-phase, 400Hz, 115 V AC power. It specifies 18 different test methods:

  • Test Methods TAC 101 – 110 describe tests under normal operating conditions.
  • Test Method TAC 201 describes a test under transfer conditions.
  • Test Methods TAC 301 to 303 describe tests under abnormal conditions.
  • Test Method TAC 401 describes a test under emergency conditions.
  • Test Methods TAC 601 to 603 describe tests under power failure condition.

For every test method, MIL-HDBK-704-3 defines a detailed test procedure. Test Method TAC 109, ‘Normal Voltage Transients’, for example, specifies:

  • Overvoltage transients, which consist of step changes from 115 V nominal to 140 V, 160 V, and 180 V with durations of varying length.
  • Undervoltage transients, which consist of step changes from 115 V to 80 V and 90 V with durations of varying lengths.
  • Combined transients, which consist of step changes from 115 V nominal to 80 V and 180 V with durations of 10 ms.
  • Repetitive normal voltage transients, which consist of a step change from 115V to 90V, a ramp-up to 140V, and a ramp down to 115V.

The AMETEK Programmable Power MIL-STD-704 test software supports this test method, as well as other MIL-HDBK test methods. There is no need for additional programming. The complete test process can be accomplished by clicking on the tests you wish to perform.

For more information on avionics power testing, read the full article, A guide to avionics power testing on Aerospace Testing International’s website or contact AMETEK Programmable Power toll free at 800-733-5427 or 858-450-0085 or email

AMETEK VTI Instruments and Programmable Power meet energy industry needs

Written on May 21, 2018 at 10:56 am, by

Energy and power generation has evolved into one of the key growth industries of the 21st century. Customers depend on AMETEK VTI Instruments data acquisition and monitoring instruments and AMETEK Programmable Power power sources to deliver the accuracy and precision required to develop highly efficient and reliable products and gain a competitive edge in the global energy market.

Data and measurement integrity

Simply having high accuracy specifications alone doesn’t make AMETEK VTI Instruments the leader in delivering measurements that ensure data integrity. What sets us apart from the competition is our proven reliability and our experience supporting the world’s largest installed base of data acquisition customers for over 25 years.

Mini TC jacks allows users to connect up to 48 thermocouples to the AMETEK VTI Instruments EX1048A 48-Channel Precision Thermocouple Measurement Instrument.

Designs that incorporate integrated signal conditioning and internal end-to-end self-calibration give instruments like our EX1048A 48-Channel Precision Thermocouple Measurement Instrument the ability to measure calibrated thermocouples with accuracies that are within +/- 0.2 degrees C.

Simple and easy to use

Setting up a test for a gas turbine generator can be time consuming and costly with most commercial instruments because of cumbersome interface schemes that turn field wiring into a difficult chore. AMETEK VTI Instruments’ integrated solutions provide direct connections to thermocouples and eliminate the need for external reference junctions, patch panels or terminal blocks.

In addition, our turnkey ‘set up and go’ software solutions means you don’t have to waste valuable time developing custom application code or attending expensive training sessions that can further delay your time to production.

Accurate PV Array Simulation

Residential and commercial solar energy systems are rapidly emerging as a “renewable energy” alternative to utility-supplied power. For microgrid, energy storage, and inverter test applications, the AMETEK Programmable Power TerraSAS™ Standalone TerraSAS Photovoltaic Simulator emulates the dynamic electrical behavior of a terrestrial PV solar array. They offer low output capacitance and high closed loop bandwidth to keep up with the advanced Maximum Power Point Tracking (MPPT) algorithms used in today’s grid-tied inverters. Output power ranges from 850 W, to test the latest generation of microinverters, to 15 kW to test utility-scale inverters.

Distributed open architecture and precise data synchronization

Since the world’s leading energy research companies often place their test solutions in remote environments, AMETEK VTI Instruments and AMETEK Programmable Power provides users with unmanned measurement capability.

Our highly distributable solutions are based on the LXI specification, which is an industry standard for LAN supported by over 50 leading instrumentation suppliers. It delivers unparalleled synchronization of distributed measurement data. Using our LXI solutions, data from generators in South America can be viewed and synchronized by engineers in California, Japan, or anywhere with Ethernet access.

We have proven experience in the following industries and can help architect the right system that meets the application’s requirements:

  • Gas turbines generators
  • Steam generators
  • Nuclear power
  • Renewable energies – wind, wave, solar or fuel cells

SG Series Provides Excellent Load Regulation

Written on April 23, 2018 at 6:37 am, by

The Sorensen SG Series is designed for exceptional load transient response, low noise and the highest power density in the industry. With a full 15 kW available down to 20VDC output in a 3U package the SG Series leads the industry in power density. The power density is enhanced by a stylish front air intake allowing supplies to be stacked without any required clearance between units.

To achieve the highest level of load regulation, the SG Series has remote sense capabilities. Remote sensing allows the supply to measure the voltage directly across the load. It then uses this value to regulate the power supply output. The result is a regulated voltage at the load that’s independent of any load line drops. SGA Series voltage regulation specifications apply for line drops of up to 10% of full-scale voltage on 40V to 100V models and up to 4% of full-scale voltage on 160V to 600V models.

Line drop voltage regulation test

To test how well the SG Series is able to handle load line drops, we connected an SGA160/63D-0AAA as shown in Figure 1.

Figure 1.

We then set the power supply output to 80V with no load and disabled the unit. The voltage setting was not changed for the remainder of the tests. We then performed three series of tests to quantify the regulation response when high load line drop is experienced while utilizing remote sensing at the load.

Test Series #1

While maintaining a constant load line resistance, we varied the user load and measured the difference between the programmed voltage value and the actual voltage measured across the user load.

Table 1.

Test Series #2

Test #2 is similar to Test #1, but we set the load at 5 Ω and used an unbalanced load line drop by placing a load in just the negative lead and then in just the positive lead with ~ 18V drop in each leg.

Table 2.

Test Series #3

Test #3 is similar to Test #2, but we increased the unbalanced load line drop to approximately ~ 36V drop in each leg.

Table 3.

The SGA power supply performed exceptionally well in all three tests. Even when a load-line drop over 22% of the full-scale voltage (35.48V) was introduced, the power supply remained well within its regulation specification for both voltage and current. Specifically, the limit for the SGA160/63D-0AAA is + 32mv and the maximum regulation disparity was only 8mv. This was the case whether the load line drop was balanced or not and equates to a load regulation of 0.005% of the rated output voltage.

For more information on the SG Series or any of AMETEK’s programmable power supplies and programmable loads, contact an authorized AMETEK Programmable Power sales representative by visiting AMETEK Programmable Power also can be contacted directly toll free at 800-733-5427 or 858-450-0085 or at

Next generation power supply feature touch-screen display

Written on April 6, 2018 at 12:58 pm, by

The Sorensen™ SGX Series is the next generation of our successful SG Series of programmable DC power supplies. Like the SG Series, the SGX Series has exceptional load transient response, very low noise, and high power density. What sets the SGX Series apart is the new touch screen display. This new feature makes the Sorensen SG Series of programmable DC power supplies even easier to use.

Users can quickly and expertly control the DC supply with the intuitive touch screen display. The touch screen function group icons include a Dashboard, Output Programming Parameters, Measurements, Sequencing, Configuration, Control Interfaces, Applications, and System Settings. Function selection and parameter entry can be achieved either by direct selection from the touch screen or by using the encoder selector button. The control resolution is adjusted by a dynamic rate change algorithm that combines the benefits of precise control over small parameter changes with quick sweeps through the entire range.

In addition to the intuitive touch screen display, the SGX Series offers test system builders a variety of features and options designed to simplify system configuration and testing processes:

  • Output power up to 15 kW in 3U and 30 kW in 6U: At the heart of the SGX is a 5 kW power module. Depending on the output voltage, one to six modules can be configured in a single chassis to deliver 5 kW to 30 kW of power.
  • Easily parallel chassis for up to 150 kW: Up to five units can be operated in parallel to provide additional current output. Paralleled units operate like one single supply providing the total system current.
  • Automatic crossover from constant voltage to constant current operation.
  • Fast load transient response: The supply recovers within 1ms to ±0.75% of full scale of steady state output for a 50% to 100% or 100% to 50% load.
  • Power factor > 0.9 typical: Power factor correction (PFC) comes standard in 10V, 15V, 20V, 30V, 50V, and 1000V models. PFC is available as an option in all other models.
  • Standard RS232 and LXI Ethernet: Optional IEEE-488.2 GPIB and isolated analog I/O interfaces available.
  • Blank panel (no display) versions available for slave units: The blank panel version protects ATE from manual or accidental parameter changes.
  • Onboard intelligent controls enable sophisticated sequencing, constant power mode and save/recall of instrument settings. Additionally, looping of sequences makes the SGX ideal for repetitive testing.

Applications for the SGX Series are wide ranging, including rack-mount ATE, product validation, process control, burn-in, materials research, battery charging, water treatment, electrolysis, accelerator magnet drive, and power electronics testing among others.

The popular Sorensen SG product family; now at 96 models, is one of the industry’s largest DC power supply families. The SGX product line complies with all EMI and EMC Safety requirements as well as EU RoHS directives.

For more information on the SGX Series or any of AMETEK’s programmable power supplies and programmable loads, contact an authorized AMETEK Programmable Power sales representative by visiting AMETEK Programmable Power also can be contacted directly toll free at 800-733-5427 or 858-450-0085 or at

Time Stamping for Multi-channel Data Acquisition Systems

Written on March 26, 2018 at 11:19 am, by

For multi-channel data acquisition systems, getting the correct readings in the correct timed order is crucial. System designers have two options for acquiring data in a deterministic fashion. They can use a real-time operating system (RTOS), that has a known buffer delay/ processing order or acquire data with a time-stamp for every sample and use precise hardware triggers and an accurate clock.

For some applications, the right choice is an RTOS. There are some limitations, however. The two biggest limitations are test system development time and the efficiency or speed of the application. Applications in a RTOS environment need to be written to achieve the desired deterministic output; interrupts, delays and wait states must all be tightly controlled.

By contrast, DAQ systems that use time-stamped data can process the data using a standard, off-the-shelf host PC with a general-purpose OS in any order and with event-driven or time-sharing buffer delays. It still forms coherent deterministic time-ordered data as each sample has an individual time stamp. The important part of this system is having a stable, accurate clock that all the DAQ instruments use. Such clocks can include but are not limited to Global Positioning System (GPS), NTC, Temperature Compensated Crystal Oscillators (TCXOs), etc.

LXI (LAN eXtensions for Instrumentation) is a popular industry standard that enables time-stamped data and scalability. LXI allows system developers to build test and measurement systems quickly because it is based on the low-cost flexibility and expandability of Ethernet. To provide accurately time-stamped data, LXI systems have the following features:

  • LXI Wired Trigger Bus
  • LXI Event Messaging
  • LXI Clock Synchronization
  • LXI Time-Stamped Data
  • LXI Event Logs

One clock method that offers extremely accurate timed data over LXI is described in IEEE-1588-2008, “IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems,” Commonly known as Precision Time Protocol version 2 (PTPv2), this method uses a GPS signal to control a master clock that synchronizes the instruments connected to a network.

Figure 1 (right) is a timing diagram that illustrates how IEEE-1588 synchronization works. The master clock sends a synchronization message with a time value to the connected slaves. At the same moment, the time at which the message leaves the master is accurately measured. The master then sends this complete exact transmission time of the corresponding sync message to the slave instruments in a second follow-up message. The slave instruments accurately measure the reception time of these messages and can correct their own clock values to match the master. At this point, if the transmission line had no delay, both clocks would be synchronized.

In the second phase of the synchronization, the delay measurement determines the run time between master and slave. This transmission line delay is determined by a Delay Request and Delay Response message; the slave instruments then update their clocks to take account of the delay. This clock adjustment to determine transmission line delay happens continuously and does not affect data transmission.

With time-stamped data, the biggest drawback is the extra processing needed to handle the time-stamp data, but this drawback is relatively minor. If all the instruments in the test system are LXI-compliant, then the time stamp has the same format and is easy to work with.

Using instruments with time-stamped data rather than an RTOS greatly reduces the time needed to develop, upgrade, or re-roll test and measurement systems. For small embedded systems, an RTOS is normally the preferred solution, but for large, expandable test systems, using a general-purpose OS is the way to go.

Building these systems with LXI instruments with multiple trigger bus lines can easily provide a quick and low-cost route to obtaining deterministic data. Adding a GPS clock and an IEEE-1588 master to the system further improves the timing of data and gives an accuracy of less than 100ns over a large network.

VTI offers the SentinelEX instrument line, all equipped with an LXI interface, IEEE-1588 precision time source, and multiple bidirectional trigger lines. For more information about the SentinelEX and other VTI products, contact VTI Instruments phone 949.955.1894 or send an email to

Analog control for the Sorensen XT and HPD Series power supplies

Written on March 13, 2018 at 7:58 am, by

The Sorensen HPD Series provides 300 watts in a quarter–rack wide chassis. It is ideal for OEM applications where wide adjustment of output voltage or current is required in a compact package, providing up to 300 watts of clean power.

Today, when we think about controlling the output of a power supply, we usually think about digital control via a USB port or some other network interface. That’s not the only way to control a power supply, though. Analog control is still used in many industrial applications, and it’s also a good choice if you have fairly simple control needs.

The optional Analog Programming (APG) Interface allows you to control the Sorensen XT and HPD Series DC power supplies with either 0-10 VDC signal or a 0-10 kΩ resistance. You connect these signals to the power supply via a female DB-25 connector on the unit’s rear panel.

The APG’s interface provides the following features:

  • Programmable output voltage and programmable current limit using either a 0-10 VDC programming signal or a 0-10 kΩ resistance. In this mode, both the offset and range are externally adjustable.
  • Fixed programming of output voltage and/or current limit using an available 10V reference (10mA max source).
  • 0-10 V readback of output voltage and current with externally adjustable offset and range.
  • Status signals for programming mode, operating mode, OVP (over voltage protection) flag, and output fail flag.
  • Adjustable over-voltage protection (OVP) with reset and flag.
  • TTL shutdown with selectable positive or negative logic.
  • Tracking for multiple supplies of the same output.

The performance specifications are shown in Table 1 below.

Remote Analog
0-10 VDC for 0-100% of rated
voltage or current ±0.1%,
0-10 kΩ for 0-100% of rated
voltage or current ±0.1%
 OVP Trip Range 3V to full output + 10%
Remote ON/OFF 2 to 25Vdc high. <0.8Vdc low.
User-selectable logic
Tracking Accuracy  ±1%

Table 1. APG specifications

As an example of how to use the features of the APG interface, let’s look at how to program the supply’s output voltage with a 0-10 VDC voltage source:

  1. Select remote voltage programming by moving the rear panel switch S1-5 (remote voltage program select) to the ON (closed) position. Or, connect J5 pin 7 (remote voltage program select) to J5 pin 6 (auxiliary ground). As these two control functions are wired in parallel, they function as a logic OR.
  2. Connect the voltage source between pin 17 (voltage program) and either pin 4 or pin 5 (program return).
  3. Vary the external voltage from 0-10 VDC to cause the power supply output to vary from 0-100% of rated output voltage. You may set the power supply’s output current limit using another source or the front panel current limit control.

The procedure for programming the output voltage with a 0-10 kΩ resistance and programming the output current with either a 0-10 VDC signal or a 0-10 kΩ resistance is very similar to this.

For more information on how to use remote analog programming, or isolating control signals, contact AMETEK Programmable Power via e-mail or call 800-733-5427.

Powering an EX1401 with POE

Written on March 6, 2018 at 12:25 pm, by

VTI EX1401

Power over Ethernet (POE) is a technology that enables network cables to carry the electrical power required by the end devices to which they are connected. One of the features that makes the EX1401 16-Channel Isolated Thermocouple and Voltage Measurement Instrument so useful is that can derive is power from Ethernet ports that support POE.

There are two types of POE ports: POE (IEEE 802.3af) and POE+ (IEEE 802.3at). POE ports supply up to 15.4 watts over Cat5 cabling, while POE+ ports can supply 25.5 watts. In most applications, the EX1401 requires a POE+ port to function properly.

Powering an EX1401 with POE offers several advantages:

  1. Reduced wiring. Because POE uses network wiring infrastructure already in place, there’s no need to purchase special cables/connectors. Commercially available CAT-5e (or higher grade) cable can be used to power up the instrument. Similarly, there’s no need to hire a separate electrical contractor for setting up electrical power ports near the test area.
  2. Flexibility: Because they aren’t tethered to an electrical outlet, distributed data acquisition systems and wireless access points can be located anywhere they are needed and repositioned easily if required.
  3. Reduced installation time. Installing networking infrastructure is typically easier and less costly than installing wall power sockets. This is especially true for temporary setups.
  4. Safety: Because the voltages involved in PoE are much lower than AC mains power voltage levels, PoE is quite safe for untrained operators.
  5. Reliability: The devices that are pumping the power into the network can be easily backed up by a centralized uninterruptible power supply (UPS). This eliminates the need for individual UPS connections at each installation location, reducing cost.
  6. Reboot Convenience: When the instrument must be rebooted/power cycled, it can be done without making physical contact with the instrument. This is done by switching off the power to the selected instrument from the Ethernet switch itself programmatically.

Here are some frequently-asked questions about using the EX1401 with POE:

Q: What’s the longest cable that I can use to power PoE/PoE+ instruments?
A. The maximum cable length is 100 meters.

Q. What would happen if I plugged an EX1401 16-channel isolated thermocouple and voltage measurement instrument into a PoE-only port?
A. Because the maximum input power required by the EX1401 is 15 W, it may or may not work with a POE. Port. To ensure stable operation, we recommend powering it only with PoE+ ports.

Q. Can I operate an EX1401 without PoE? Is there any alternate ways of powering it?
A. You can power the EX1401 using any clean DC power source with an output voltage between 11 VDC and 30 VDC.

Q. Can I connect PoE+ devices and instruments and non-PoE devices (traditional LXI) devices to the same PoE+ enabled switch?
A. Yes. When you connect a traditional LXI device to a POE+-enabled switch, the switch behaves like a regular network switch.

VTI Instruments delivers precision modular instrumentation and systems for electronic signal distribution, acquisition, and monitoring. For more information about the EX1401 and other VTI products, contact VTI Instruments phone 949.955.1894 or send an email to

SL Series electronic loads offers four kinds of protection

Written on February 22, 2018 at 11:16 am, by

The Sorensen SL Series of electronic loads is one of the most versatile on the market.

The Sorensen SL Series of electronic loads are not only a great value, they are available in a wide variety of configurations, making them one of the most flexible electronic loads on the market. Models are available that provide both AC and DC loads, with input power ranging from 75 W to 1,800 W, and they are available in benchtop, modular and standalone form factors.

As you know, testing can be a precarious proposition. Device under test (DUT) failures can lead to abnormal operating conditions that can damage test equipment. To prevent this from happening to your electronic loads, the SL Series has five protection mechanisms:

  • Over-voltage
  • Over-current
  • Over-power
  • Over-temperature
  • Reverse polarity

Over-voltage protection (OVP)

The over-voltage protection circuit is set at 63 V for all SL-series electronic loads. This voltage is not settable by the user. Should the voltage at the input terminals exceed 63 V, the over-voltage condition is triggered, and the device under test is internally disconnected from the load. When an over-voltage condition is triggered, the upper five-character display indicates “Prot,” and the lower five-character display indicates “oVP”.

Note that you should never apply an AC line voltage to your load. This can damage the load. The OVP circuit does not protect against severe over voltage conditions, and voltages above 100 V will permanently damage the electronic load, requiring factory repair.

Over-current protection (OCP)

The SL Series loads monitor the load current, and should the current measured be higher than 102% of programmed current, the load will turn itself off. When the over-current condition is triggered, the upper five-character display indicates “Prot,” and the lower five-character display indicates “oCP”.

Over Power Protection (OPP)

The SL Series loads also monitor the power dissipation of the load module, and should the power dissipation reach a level greater than 102% of programmed power input, the load will turn itself off. When the over-power condition is triggered, the upper five-character display indicates “Prot,” and the lower five-character display indicates “oPP”.

Over Temperature Protection (OTP)

The SL Series loads have temperature sensors on the heat sinks internal to the unit. If the temperature of the module’s heat sink rises to greater than 90° C, the load turns itself off, and the over-temperature protection is triggered, and the upper five-character display indicates “Prot,” and the lower five-character display indicates “otP.” The unit will remain off until until the heat sink temperature drops to 70° C or below.

Quite often, an over-temperature condition is the result of poor ventilation. Check the environmental requirements spelled out in the operation manual and ensure that the distance between the rear panel of load mainframe and wall is greater than 15 cm.

Reverse polarity protection

The SL Series conducts reverse current when the polarity of the DC source connection is incorrect. If the reverse current exceeds the maximum reverse current, the unit will turn itself off and the upper five-character display indicates “Prot,” and the lower five-character display indicates “-V”, a negative current reading. Whenever a reverse current reading is displayed, turn OFF the DC power source immediately and make the correct connections.

For more information about input protection of the Sorensen SL Series, or about electronic loads in general, please contact AMETEK Programmable Power by sending email to or phoning 800-733-5427.

EXLab Express Acquires Data Without Programming

Written on February 14, 2018 at 11:56 am, by

EXLab Express is a powerful, easy to use, plug and play data acquisition software package that allows users of the EX1401 Thermocouple/Voltage Measurement Instrument to acquire data without programming. But, not only is it powerful and easy to use, it’s free!

EXLab Express simplifies instrument configuration, acquisition and data display without sacrificing functionality or performance. EXLab Express features include:

  • Intuitive, icon-based setup and control
  • Spreadsheet-style channel configuration
  • Snapshot display with data export
  • Independent sampling rates for each instrument
  • Real-time online graphical data analysis

These features allow users to be up and running in minutes, not days or weeks. For example, the spreadsheet-style setup screen allows users to easily select the channels they want to acquire data from, specify the type of transducer connected to a channel, and configure the units of measurement and any warning and alerts associated with a channel.

Once the channels are configured, users can start data acquisition by simply clicking on an icon. During the data acquisition, users can “snapshot” the data. What this means is that the user can monitor the data acquisition to ensure that a test is running properly. An example of the data snapshot screen is shown below.

Once a test is complete, EXLab Express allows users to play back, display, and export data. All of these options make it easier for the user to make sense out of the data and take action on it.

To download EXLab Express, click here. For more information about EXLab Express, contact VTI Instruments directly at 949.955.1894 or