What Is ISO 7637?
The ISO 7637 series defines test methods in which transient voltage pulses resulting from events such as switching and inductive load interruption in the vehicle electrical system are applied to component lines. Pulse types (pulse 1, 2a, 2b, 3a, 3b) are determined in the standard.
Purpose of ISO 7637
The aim is to verify that the component is not damaged and continues to function during transient pulses in the vehicle supply line.
Which Products Is ISO 7637 Applied To?
- Electronic control units
- Sensors and actuators
- Lighting modules
- Infotainment systems
- Electric drive auxiliary components
In Which Sectors Is ISO 7637 Used?
Standards Related to ISO 7637
- ISO 7637-1electrical transients conducted in vehicles test
- ISO 7637-2electrical transients conducted in vehicles test
- ISO 7637-3electrical transients conducted in vehicles test
- ISO 16750-2Environmental conditions in vehicle electrical/electronic equipment test
- UNECE R10electromagnetic compatibility in vehicles test
ISO 7637 Conditions
- Darbe tipleri
- Pulse 1, 2a, 2b, 3a, 3b; each with different amplitude and duration characteristics
- System voltage
- Parameters vary depending on 12 V, 24 V or 48 V system
- Number of shocks
- Standard-defined number of repetitions for each type
- Application
- Directly (ISO 7637-2) or by coupling (ISO 7637-3) to the supply line
Equipment for ISO 7637
- ISO 7637 pulse generator
- Coupling–decoupling scheme
- Oscilloscope and pulse verification scheme
- Function-monitoring system
Sample Requirements for ISO 7637
- System voltage and supply arrangement must be documented
- Function monitoring and acceptance class must be defined
- Load simulators should be installed
- Function must be checked before the test
Duration of ISO 7637
It depends on the type and number of pulses; typically one business day.
ISO 7637 Procedure
- 1The types and levels of impact to be applied are determined.
- 2Pulse patterns are verified with an oscilloscope.
- 3Pulses are applied to the sample feed line.
- 4A defined number of repetitions are made for each type.
- 5Function is monitored continuously.
- 6Permanent damage is checked.
ISO 7637 Acceptance Criteria
Acceptance criteria are given according to classes A, B, C, D, E in ISO 7637-1. Generally, no damage is required for pulses 1 and 2, and continuity of function is sought for pulse 3.
Evaluation of Results
Which type of impact occurs is recorded. This information provides direct input into the input protection circuit design.
ISO 7637 Report
- Applied standards and impact types
- System voltage and levels
- Pulse verification records
- Function observations and acceptance class result
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- UNECE R10
- Automotive OEM specifications
EMC / EMI Testleri — What Does This Testing Field Cover?
The section below describes the field that the ISO 7637 test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
EMC testing answers a question with two sides: does the device emit an unacceptable level of electromagnetic interference into its surroundings (emission), and does it withstand the interference coming from them (immunity)? The two sides are measured with separate tests and separate set-ups, and both are required.
The field exists because of a simple physical fact: every conductor carrying current behaves like an antenna. A switched-mode power supply, a motor drive or the clock signal of a microcontroller radiates radio frequency energy even though it was never designed to. The same conductor also works in reverse: an external field induces a voltage across it. In an environment crowded with devices, this mutual effect means devices disturbing one another.
On the emission side, conducted and radiated emission are measured separately. Conducted emission is the interference the device imposes on its mains and communication cables and dominates at lower frequencies. Radiated emission is the field the device releases into the air and comes to the fore at higher frequencies. The two are measured in different set-ups, and the limits vary by product group.
On the immunity side, real-world sources of interference are simulated: electrostatic discharge (human touch), radiated radio frequency fields (a nearby transmitter), electrical fast transients (switching), surges (lightning and mains events), conducted radio frequency, power-frequency magnetic fields, voltage dips and short interruptions.
The standard to be applied depends on WHERE the product is used, and that choice determines the entire outcome. Residential and industrial environments carry different sets of limits; in vehicles the UNECE R10 regime applies rather than CE; for medical devices IEC 60601-1-2 brings additional requirements; and for products containing a radio, radio legislation comes into play and harmonised ETSI standards are used.
In immunity testing the acceptance criterion is a PERFORMANCE CRITERION class, not a binary pass/fail. A device continuing to function without interruption during the test, being temporarily affected and recovering by itself, or recovering only through user intervention are different classes. Which class is acceptable is defined in the product standard; the tolerance for a device carrying a safety function differs from that of a consumer device.
The most common shortcoming of an EMC file is that it covers only one side. A file carrying an emission report alone is not complete in terms of the EMC directive. The second common gap is a test set-up that does not represent actual use: if the device is measured on a bare bench with cables different from its real ones, the result does not carry over to the field.
Method groups in this field
Conducted emission
Interference imposed on the cable through mains and communication ports, measured via an artificial mains network (LISN).
Radiated emission
The field released into the air by the device, measured at a defined distance in an anechoic or semi-anechoic chamber.
Harmonics and flicker
The harmonic content of the current drawn from the mains and voltage fluctuation; the side that affects mains quality.
Electrostatic discharge
Contact and air discharge together with indirect discharge; the most frequently applied immunity test.
Radiated and conducted RF immunity
The device is exposed to a defined field strength and to an RF signal injected into the cable.
Mains-borne events
Electrical fast transients, surges, voltage dips and short interruptions.
Commonly confused in this field
- An emission report alone does not complete an EMC file; immunity must be demonstrated as well.
- An FCC report is not accepted in a CE file; the limits, measurement distances and set-ups are different.
- The EMC Directive does not apply to vehicles; the UNECE R10 regime does. Specifications requiring both together should be reviewed.
- The warning that a Class A device may cause interference in a residential environment is mandatory in the manual; market surveillance checks that this warning is present.
- The test set-up is part of the report. If cable type, length or routing changes, the result changes; measurement must be made in the series-production configuration.
- CISPR 22 and CISPR 13 have been withdrawn; their current counterparts are CISPR 32 and CISPR 35.
Which decisions these results support
- CE declaration under the EMC Directive
- The EMC part of radio equipment conformity
- A UNECE R10 file for a vehicle component
- Resolving field interference complaints and correcting the design
- Assessing the EMC impact of a board or wiring-harness change
Related Tests
Frequently Asked Questions About ISO 7637
According to which standard is ISO 7637 made?
ISO 7637 is executed in scope ISO 7637-1, ISO 7637-2, ISO 7637-3, ISO 16750-2 and UNECE R10. The limit values and acceptance criteria to be applied are defined in the product standard; The version valid for your product is confirmed in writing at the offer stage.
Which products does ISO 7637 apply to?
Mainly applied to Electronic control units, Sensors and actuators, Lighting modules, Infotainment systems and Electric drive auxiliary components. Whether your product is included in the scope is determined by examining its technical specifications and intended use.
Under what conditions is ISO 7637 done?
The determining parameters are: Darbe tipleri — Pulse 1, 2a, 2b, 3a, 3b; each with different amplitude and duration characteristics, System voltage — Parameters vary depending on 12 V, 24 V or 48 V system and Number of shocks — Standard-defined number of repetitions for each type. The full terms are in the "Test Conditions" section on the page and vary depending on the product standard.
What kind of sample is needed for ISO 7637?
System voltage and supply arrangement must be documented, Function monitoring and acceptance class must be defined and Load simulators should be installed. The number of samples is determined according to the product standard and the scope to be reported.
How long does ISO 7637 take?
It depends on the type and number of pulses; typically one business day. This duration belongs to the experiment itself; sample preparation, queuing and reporting are also evaluated. A realistic schedule for your product is given in the offer.
What is the ISO 7637 result called "appropriate"?
Acceptance criteria are given according to classes A, B, C, D, E in ISO 7637-1. Generally, no damage is required for pulses 1 and 2, and continuity of function is sought for pulse 3.