For energy measurement tests surge generator design (1)

IEC 60601-1: 2006, connected to the patient's medical device must resist defibrillation (that is, the medical devices can be simultaneously with defibrillator and patient connection, can resist the defibrillator work release of high energy and not damaged).

IEC 60601-1 contains medical device's General requirements for safety.

Over the years, these requirements have been improved and more inclusive. Surge test many years ago had already been incorporated into the IEC 60601-1 standard, surge test is to ensure that the patient after exerting defibrillation pulse, connected to all patients with medical equipment still functioning.

IEC 60601-2006 proposed energy measurement test requirements, the aim is to ensure to patients of defibrillation pulse energy are connected to the patient's medical device consumes part does not exceed defibrillation pulse 10 per cent of total energy.

Overall, energy calculation test has appeared in IEC 60601-2-49, has now been added to the IEC 60601-1-2006 Edition. In both of these standards, is using the 5-kV capacitors, but many other parts of the tolerance values are different. Figure 1 shows the common mode and differential-mode test in the circuit. These are IEC 60601-1 contains testing and test methods and the same as before. Figure 2 shows the energy measurement test the circuit, this is a new test.

Figure 1. For anti-defibrillation-application components in a single patient connection test voltage circuit

In order to get accurate test results, energy measurement test requires a different test methods as well as on the surge generator to do that.

We found that for common mode and differential-mode tests of the old generator may not be able to do on energy metering and test appropriate assessment. If you want to know if a generator is available, you can check its front or back panel, check to see if it is below 40 Ω 0 and 100 Ω resistor between nodes configured with energy metering port (see Figure 2). If the generator configuration has an energy measurement port, it must also be checked before and after in shipping, ports and impulses between the resistance values, ensure its resistance value in 100 Ω nominal values of 5% or less. If the surge tester can meet these two conditions, then it can be used to make energy measurement test.

Design for energy measurement tests surge generator

IEC 60601-1 in the third edition: the energy measurement and inspection, the operator you want to do two tests: the test equipment and surge generator disconnected test; the test equipment (DUT) and surge generator connected cases test it once again.

If two energy measurement test results showed that the absorption of DUT pulse energy in total energy pulse 10%, so that the measured energy metering equipment has passed the test. Surge tester of designers and technicians must use special methods to ensure that the test and correct manner.

IEC 60601 provides energy metering testing roadmap, but there is no requirement to get waveform.

Therefore, surge Tester manufacturers must ensure that surge Tester itself on the accuracy of, or produced waveform is not accurate. Figure 3 on is not connected to the DUT, energy measurement test output for simulation, it is assumed that the use of real parts.

Figure 2: standard new given voltage model, used for testing are delivered by defibrillation energy.

Due to the IEC standard specifies components 60601 and deviation range, so to get the correct generator output waveform doesn't need ISO accredited calibration 17025.

To get the correct output waveform, inductors or exclusion (Resistor Bank) to elaborate design.

Configure a 100 Ω exclusion of surge tester, it is possible that it could have passed ISO 17025 calibration, but sent a surge (spikes) may have no tolerance range.

Because power calculation formula contains the resistance values, to receive accurate results, the resistance values called resistor in a surge through the cause of fever will not change. Because energy measurement test to test the two, let the resistance value for the duration of the test remains the same, it is also important.

Resistor whenever used in circuit is fever, resistor heating be resistance values decline.

The resulting changes in electrical resistance value is defined as a resistor manufacturers. temperature coefficient Due to the surge ahead through thermal impact resistance value changes, altering power measurement results. If resistor heating to a certain degree it resistance values in two tests when drastic change, more pulse energy in the second test is the exclusion, the energy transmitted to the DUT. If the exclusion in the fever after resistance exceeds the allowed deviation range, then this will cause the test device test results cannot be tested.

If the exclusion of resistance value no, then the exclusion when transmitting pulse heating may cause inaccurate energy metering data.

This is because the energy calculation formula assumes that the resistance during the testing process constant, however this is not the case. In actual use, rated exclusion in a pulse through, its resistance values occur < 5%, and in the continuous and pulse, the resistance values occur within 5%. By assigned to surge tester's duty to control the 5 per cent of the pulse-pulse precision. In order toEnsure the accuracy of the energy calculation, this author recommends that before and after the test immediately to 100 Ω exclusion of resistance measurements, and the average value for the energy calculation formula of the R value.