Design of an automated test system for power supply testing

Having difficulty designing your fitting room?

Designing and conceptualizing an ATE is not an easy task.

Here are some points and steps you can consider when designing your own Automated Test Equipment (ATE) to suit your needs.

Coverage test:

List all existing power supplies, newly developed power supplies, and future projects with the following required information:

o Input Power Requirement – ​​For input source, you need to plan what input source you may need to cover all input requirements for all your product lines.
o Output Power Requirement – ​​number of loads to consider, this will vary from the high power range to the low power range.
o Number of outputs and signals: This is very critical as you have to plan the standard mux assignment. For this, the more mux assignment, the better.
o Control Switches – Review each test requirement for each of the products for all tests that require relays or switches. You have to be very careful when planning this. This will be used to determine how many general purpose switches or relays you will install in your ATE. You can also check out the new testing methodology that might be possible to test the new products.

From the list, you must complete the following information:

o You will have an idea of ​​which input source to use to cover the entire power supply you are about to test.
o You will have an idea of ​​how many load modules you need to install to cover high power multi-output power supplies. You will also need to add a low current charging module for lower current outputs.
o You will have an idea of ​​how many muxes and switches you are going to use.

panel interface test

You need to consider the test interface you are going to use for your ATE. There are many options on the market.

For the test panel connector, you should note the following:

o Quality of contacts, good contact probes to eliminate contact resistance that will affect your measurements.
o Flexibility, easy to plug in, easy to unplug, quick disconnect, low insertion and removal force required.
o Serviceability, easy to replace. You should also note the connector that is easy to replace and
keep.
o Contact life cycle, you should consider the long life cycle connector; if not, you need to change it frequently.

Test equipment

You should consider the following points to select a team.

o Availability of equipment – make sure you have a permanent team for your ATE.
Since the equipment will be fixed on your ATE, make sure that the equipment is not shared with another test setup.
o Equipment communication interface, generally all equipment has GPIB (general purpose interface bus) for remote control.
o You should also consider that when building ATE, this will be a standard test setup. You can build more ATEs using the same setup from hardware to software. In this sense, it is necessary to consider equipment that is still available on the market in case more ATEs need to be built.
o Ease of service, consider equipment that still has technical support from the manufacturer.
o Easy to install in your ATE Rack, test sets are usually standard size, usually 19″ wide that will fit in the 19″ rack.

capes

Use the correct cables for your ATE.

o Load cables: Use cables rated that can handle the maximum current rating of each module. Be sure to account for only 80% of the cable capacity.
o Sense Wire for voltage sensing on your DVM: Use a stranded wire for sensing on your DVM.
o Sense cable for the oscilloscope: use shielded coaxial cable, scope probes.
o Input cables for input:
For AC, be sure to check the cable’s rating. Make sure the ground is also connected. Use a thin stranded wire for the sense.
For DC, be sure to check the cable’s rating. Use a thin stranded wire for the sense.
o Input cables for equipment input: always connect the ground of each equipment to the main input ground.
o GPIB cables for remote programming

Here is the common configuration of the ATE test equipment

o Oscilloscope (4 channels)
or DVM (6.5 digit resolution)
o Differential probes for input
or switch control
– 10 muxes (or more)
– 10 general purpose relays (or more)
– 10 DIN
– 10 Doubts

o Electronic Charges:
– 16 – 300W load
– 2 – Load Module 150 W or less wattage

or input source
– 6.5 KVA AC source
– 2 KW DC source (parallel with additional source)

power meter

or Auxiliary Sources
– 12 V DC standby
– 5VDC standby

or I2C interface

o Computer with GPIB interface for the device and a USB or serial interface for the i2c driver.

o Power Bars o Power distribution unit for equipment input supply.

Assembly of your ATE

o Rack Assembly – If you plan to use a two rack system to accommodate all of your ATE equipment, connect the two racks together with a bolt and nut, remove the cover in the middle of the rack for easy access to both racks.
o Install all mounting brackets for each piece of equipment
o Equipment Mounting: Use equipment railings when setting up your equipment. Usually, the assignment of each piece of equipment is important in the wiring process. For my opinion, I put all connected equipment on the secondary side of the power supply on the left side (if you are facing the rack).
o Left side of the rack: This equipment will be connected to the secondary side of the UUT.

– Oscilloscope
– DVMs or Data Acquisition
– switch control
– Electronic charges

o Right side of the rack: This equipment serves as the source for the UUT.

– Input source
– Axillary springs
– Power counter

o Bolt the mounting bracket of all equipment to the rack.

Note: Record all rail assignment for documentation purposes.

Wiring your ATE

Wiring and ATE are very critical and will greatly affect your measurements.

Here are some steps and tips you may need to consider when wiring your ATE.

o Wire the equipment input first. Make sure the input cables for the equipment are on one side of the rack (the leftmost side if you are facing the rear of the equipment). Harness it properly with a cable tie or Velcro.
o Connect GPIB cables to all equipment. Start connecting from the oscilloscope to the
electronic loads then to the input source to the computer. Connect the GPIB cables in the same way as the AC input cables of the equipment.
o Prepare the load cables, make sure it is long enough to reach the test interface panel. Label the load cable from load 1 to load 18, both the positive (red) and negative (black) wires at both ends. Connect all load cables to the load, double check the cable rating that matches the load module rating. The load cable rating must be 20% greater than the maximum current of the maximum load module. If you are not taking any load measurements, you do not need to connect a sense wire, just set the module to local sense. Connect the charging cable separately with the input cables of the equipment. Harness it to the other side of the rack.
o Prepare the sense cables, make sure they are long enough to reach the test interface panel. Label each sense wire for each mux assignment at both ends. Connect the switcher/DVM control unit cables to the test interface panel. Connect the sense leads together with the load leads.
o Prepare the sense shield cables, make sure it is long enough to reach the test interface panel.
Label each sense wire for each mux assignment at both ends. Connect the cables from the switch/oscilloscope control unit to the test interface panel. Connect the sense leads together with the load leads.
o Wiring of the input source. The output of the AC input source must be connected through the power meter. The DC input source will be connected directly to the test interface panel. The DC input source measurement will be taken from the source itself. Both the AC and DC input sources must use a remote sensing scheme to eliminate voltage drop. Connect the input source cables separately.
o When wiring the auxiliary sources, make sure that the cables reach the test interface panel.

GPIB equipment addresses
You have to assign a standard equipment GPIB address for each of the equipment.
The valid GPIB address is from 1 to 30. Generally, the manufacturer’s default GPIB address is used, unless there is a conflict.

These are the names of other professionals called ATE

o ATE – Automated Test Equipment
o ATS – Automated Test Systems
or power test
or self test
o Mixed mode tester
o FT – Functional Tester
or CT – Computer Test