AMPTEC Research · Ruggedized Failsafe Igniter Testers
641RS
Compact ruggedized failsafe igniter tester with self-test, built for military ordnance programs
The 641RS is the meter an ordnance technician picks up when a bridgewire, fuze, pyrotechnic or explosive device has to be resistance-checked without any chance of firing it. A failsafe current-limiting network caps the test current at 8mA on every range, the whole measuring circuit sits inside a shielded Faraday cage, and a built-in self-test confirms the meter before each session. It is 40% lighter than the 640 series it replaces, waterproof, and in service with NASA and the USAF. Evencat is AMPTEC's sole distributor in Taiwan.
Overview
The AMPTEC 641RS is a compact ruggedized failsafe igniter tester designed for military ordnance programs. Its job is resistance measurement on bridgewires, fuzes, pyrotechnics and other explosive devices, with the test current held below 8mA by a failsafe resistor network no matter what fails inside the meter. A shielded Faraday cage keeps external noise out of the low-resistance readings. The self-test function uses built-in precision reference resistors, so you can verify accuracy in the field, and a self-contained DC milliammeter shows the actual test current in real time. Eight ranges span 2Ω to 20MΩ on a 4½ digit LED with accuracy to ±0.02%. The waterproof case is 40% lighter than the earlier 640 series, and the meter is UL-913 compliant and built under ISO 9001:2015. Before ordering, decide which probe or lead set you need and whether the 20MΩ insulation range matters to you; if not, the 641N covers the same bridgewire work with seven ranges.
Key specifications
| Ranges | 2Ω, 20Ω, 200Ω, 2kΩ, 20kΩ, 200kΩ, 2MΩ, 20MΩ (8 ranges) |
|---|---|
| Max failsafe current | 8mA |
| Nominal current | 5mA / 5mA / 1mA / 100µA / 10µA / 1µA / 0.1µA / 0.1µA (by range) |
| Accuracy | ±0.02% to ±2% (by range) |
| Resolution | 0.1mΩ to 1kΩ (by range) |
| Display | 4½ digit LED |
| Temperature coefficient | ±0.002% per 1°C |
| Operating temperature | 0° to 50°C |
| Max input voltage | 250 VDC |
| Open circuit voltage | 1.6 VDC |
| Dimensions | 10.62" × 9.68" × 4.87" |
| Weight | 6.5 lbs |
| Power | 4 rechargeable 5AH NICAD batteries |
| Certifications | UL-913 / ISO 9001:2015 |
Features
Failsafe current limiting
A failsafe resistor network holds the test current below 8mA on every range, so resistance can be measured directly on explosive devices.
Self-test function
Built-in precision reference resistors let you confirm the meter's accuracy on site before trusting a reading.
Shielded Faraday cage
The measuring circuit is enclosed in a Faraday cage, which keeps electromagnetic noise out of low-resistance readings.
8 ranges, 2Ω to 20MΩ
Eight ranges from 2Ω to 20MΩ with accuracy to ±0.02% cover bridgewire continuity through to insulation checks.
Compact waterproof ruggedized case
The waterproof case is 40% lighter than the previous 640 series, sized for field and military use.
Self-contained milliammeter and display
A built-in DC milliammeter and a 4½ digit LED show resistance and actual test current at the same time.
Typical applications
Military ordnance
Igniter resistance acceptance testing in ordnance programs
On munitions production lines and in magazines, ordnance technicians use the 641RS to measure explosive bridgewire resistance and confirm each initiator falls inside its safe tolerance before assembly or storage. The failsafe current limit of 8 mA keeps the test itself from initiating the device, protecting the operator and the surrounding explosives.
Aerospace pyrotechnics
Pre-shipment and pre-launch checks on NASA and USAF pyrotechnic systems
Pyrotechnics engineers at NASA and the US Air Force use the 641RS during integration and acceptance of satellite separation bolts, explosive actuators and launch vehicle igniters. The built-in self-test verifies the meter's own circuit before every measurement, so a reading is trusted before the pyrotechnic device is cleared for final integration under pre-launch safety procedures.
Field maintenance
On-the-spot checks at field depots and forward positions
Meeting MIL-STD-810F environmental testing, with a weatherproof case, 6.5 lbs and rechargeable NICAD batteries, the 641RS lets ammunition technicians verify the firing chain of ready munitions at a field supply point or forward base. Nothing has to go back to a rear depot, which shortens the readiness confirmation cycle considerably.
Options and configuration
Tick the options you need; we will assemble the configuration list and carry it into the inquiry form.
Standard equipment (included)
Series model comparison
Documents and resources
Downloads
Need pricing, specifications or lead time for 641RS?
Also available for rent: 641RS is part of the AMPTEC rental program, for project peaks, calibration backup and pre-purchase trials. Rental inquiry →