Every electrical and electronic device, which will be placed on the market in the EU, must comply with electrical safety standards and also meet the requirements for electrical emissions both radiated and conducted and it’s susceptibility to external electrical emissions, both radiated and conducted. The exact standards that must be complied with depend on the product type. To demonstrate compliance with the required standards a “CE” mark is attached to the product and a CE Certificate of Compliance, listing the standards complied with must be enclosed with the product or be made available on request. For many electrical and electronic products environmental tests such as shock, vibration, temperature and humidity are conducted to stress the device under test and to accelerate ageing in order to assess the likely reliability of the product during its operational lifetime. These Tests are known as HALT (Highly Accelerated Life Test) and HASS (Highly Accelerated Stress Screening). HALT is applied to the electrical and electronic products during their design phase. The products will be stressed to achieve an accelerated ageing. This is done to find possible problems which could occur during the lifetime of the product so the device will be stressed beyond its specified maximum specs (electrical and mechanical). Problems found based on stress testing gives designers the possibility to change the design and the production process to improve the quality of the new product before its introduction to the market. With HALT and HASS it is possible to detect quality issues during the early design phase. This saves time and money, as the later in the developing phase problems are found, the more expensive and time consuming design changes become. To run the HALT test, the device is positioned on a vibration table inside a climate chamber. The tests normally run consist of steps, for example cool down or heat up, temperature change, vibration or combined stress tests. During all these test steps, the device has to be controlled and all functions have to be monitored and checked constantly during the complete test cycle. A so called automated test solution! Let’s look at temperature measurement which is normally done on different locations, on or around the device under test (DUT), to get a complete picture of the device temperature distribution during the HALT test. To be able to measure such a temperature profile within a climate chamber, you need a robust and accurate sensor. In this case a thermocouple is the best solution. A thermocouple is simple and robust, cheap and easy to handle and they have a large temperature range. The disadvantage of thermocouples is that you need a reference junction. The compensation can be done automatically by an instrument like a DMM which is included in the M300 test system. Most of the M300 switching cards include a CJC (Cold junction Compensation) so you can measure the absolute temperature of the device. In this case it eliminates the need for an external reference for example -“ice water” compensation.
Stimulated Compensation CJC
Classic Compensation (Ice Water)
Analoge Compensation CJC
Digital Compensation CJR
Also the nonlinearity of the thermocouples is not a big problem, because the built in multimeter will convert voltage into temperature for all different kinds of thermocouples (K,J, E, etc.) They differ in accuracy and temperature ranges. Thermocouples use the so called Seebeck Effectt, which is based on the physical effect that two different metals which, when connected, generate a voltage if the temperature is different on both sides of the metal. This voltage is very low, for example a Thermocouple Type K pro 1°C changes ca. 40µV. Therefore you need a voltmeter with high resolution and accuracy like in the M300 6 ½ digit system.
The Seebeck Effect
For the complete test it is also necessary to be able to measure more than only the temperature, for example other parameters, such as voltage, current, resistance etc. It is also very useful to have math functions included in the system because you can define different types of sensors to measure e.g. pressure, movement etc. (mx-b) and also more complex sensors too. The Rigol M300 is a complete test solution with built in capability to measure a wide range of physical and electrical parameters. Measurements up to 256 points are possible for temperature, voltage, current and /or resistance with 2-wire connection, or half number of points with 4-wire connection and any combination of different signals. Besides measurements, it is also possible to control the whole process. With modules which have analog and digital outputs, we are able to react to process limits or influences, shut down or reduce or simulate the process later.
Rigol screw terminal M3TB32 with CJR
Rigol Switch-card MC3132
Integrated CJC (cold junction reference) for reference temperature of Thermocouples Built in tables of voltage for temperature conversion High resolution voltage measurements down to 100nV Digital IO cards with up to 64 lines This is just a small selection of the built in functionality of the M300 system There are many industrial application areas where it is necessary to do measurements like the above: Consumer Electrical and Electronic Products – Especially Washing Machines, Dishwashers, Cookers, Microwave Ovens etc.… Automotive – Validation in temperature chambers of electronic parts… Aerospace, Train, Telecom – climate/temperature overview in the passenger cabin, Base-Stations… Power Plants – temperature profile of cooling towers… To make the configuration and measurement much more effective and easy to use, the M300 will be delivered with PC based Software UltraAcquire. UltraAcquire Pro is the extended version of the standard software tool and allows the use of more than only one mainframe. It enables extended graphic capability, data storage and more… Below you can see an example of a typical configuration. This includes voltage measurements, resistance measurements, frequency measurements and temperature measurements with different sensor types (PT100, Thermocouple Type K, Type E, Type N). With the software you can define when data is measured, how fast the scan should be, how long the measurement is done for and how the data should be stored.
List of all different switching cards: MC3056: -DMM Module (6½ digits) MC3132: -32-channel Multiplexer MC3164: -64-channel Single-ended Multiplexer MC3232: -32-channel Reed Multiplexer MC3264: -64-channel Single-ended Reed Multiplexer MC3324: -20-voltage-channel+4-current-channel Mixed Multiplexer MC3416: -16-channel Actuator MC3534: -Multifunction Module 4x 8-bit DIO´s, 4x TOT totalizer, 4x DA converter MC3648: -4×8 Matrix Switch MC3724: -Dual 4-channel RF Multiplexer (later).