620A-4R Water Resistant - Fail-safe Ohmmeter/ Igniter Circuit Tester

The 620A-4R Fail-safe Ohmmeter
The 620A-4R Water Resistant Igniter Tester is a ruggedised, water-resistant, portable digital ohmmeter which has been specifically designed for ultra-safe resistance testing on explosive devices (i.e. squibs, igniters, flares, detonators). The 620A-4R case is waterproof when closed to a depth of 3 feet. The 620A-4R also floats in water. It can be operated outside in direct rain, as it has silicon boot seals over all switches.

Fail-safe Design - Built-in 'Can't Fail' Life Saving Features
There are a number of critical military, commercial aerospace and aircraft applications that use squibs (i.e. Boeing 777 Aircraft Fire Control Systems), EEDs (electronic explosive devices), detonators, explosive bolts, and a number of explosive/blasting devices. It is critically important that these devices detonate when properly triggered. It is also critically important that these devices do not detonate while being tested for wiring continuity/integrity. Each Igniter Tester is manufactured with redundant, dual fail-safe protection - current limiting and resistor network circuitry that limits and ensures that the instrument test currents cannot exceed the specified amount. Even in the unlikely event of a worst case component failure, the output current limiting network is still in effect.

Approved by Boeing for Testing the Boeing 777 Fire Control System
The 620A-4R Igniter Tester is approved by Boeing Aircraft for use on Commercial Boeing 777 Fire Control Systems. Since the 620A-4R Igniter Tester is ruggedised and waterproof, it can be operated in virtually any kind of weather condition.

Faraday Cage provides Electronic Noise Immunity, EMP and Static protection
The 620A-4R electronics are encased in a shielded Faraday cage (all to chassis ground) to provide additional electronic noise immunity, Electromagnetic Pulse ( EMP), electrostatic discharge (ESD) or Lightning protection.

Better and Safer than a Multifunction DMM
Multifunction DMM's have many modes (i.e. DC Voltage, AC Voltage, DC current, AC current, frequency, shift keys, Capacitance and more..) that can measure the igniter circuit resistance incorrectly. If the DMM has an electrical fault the igniter circuit may accidentally fire. The 620A-4R Igniter Tester only measures resistance, it is not a complex multifunction DMM. If the 620A-4R had an electrical fault, it offers the life saving advantage of failing safe.

No Hazardous Mercury Batteries
The 620A-4R does not use hazardous mercury batteries like those in older model igniter testers. All 620A-4R 's are battery powered with a heavy duty rechargeable Ni-Cad pack for portability purposes. A 120 VAC powered battery charger is standard.

It floats in water, and can be operated in direct rain

Polyurethane Epoxy Coated Circuit Board and More ...
A common question we get from evaluating safety engineers is "What sort of electrical and mechanical measures are taken with the 620A to prevent an internal loose wire, metal screw, or washer inside from floating around and shorting the battery output to the terminal output posts?". The ohmmeter's output posts are insulated inside the unit with heat shrink tubing covering any of it's conductive surfaces. The entire PCB (except for the calibration trim pots) is also nonconductive polyurethane epoxy coated, to make it extremely difficult to get an accidental conductive pathway. The ultimate electrical safety analysis for fail-safe current relies on "Ohms Law" for determining Imax, based upon a Vmax ( ~ 4.8 VDC battery value) divided by the equivalent circuit current limiting resistance (R-limit) for the particular version being considered. 620A circuit schematics are available upon request for reviewing the maximum fail-safe current level.

Specifications
Accuracy: (180 days 25°C ± 10°C) ± 0.02% of reading  ± 0.02% of range for 20 ohm through 20 Kohm ranges (2 Megohm range versions available - Call Permac for any ranges above 20 Kohms).
Display: 4½ digit (19999) L.E.D.  - 20,000 counts (Visible in direct sunlight (5 times brighter than high intensity LEDs)).
Terminal Configuration: Four-wire Kelvin
Overload Indication: Display flashes
Maximum Input: 250 VDC or peak AC without damage
Operating Temperature Range: 0°C to 50°C
Temperature Coefficient: ±.002% per °C (from 0°C to 15°C and 35°C to 50°C)
Conversion Rate: Approximately 3 per second
Power: Rechargeable Ni-Cad batteries (5.0 Ahr) & Charger (115 VAC 50-60 Hz) (For safety reasons, the 620A-4R Ohmmeter operation will only charge the batteries when the main power switch is in the "OFF" position).
Max. Internal Voltage: 4.8 VDC - 4 ea. 1.2 V Ni-Cads
Size: 235mm/9" D x 254mm/10" W x 76mm/3" H
Weight: 1.6 KG/3.5lbs NET 3 KG/6.5 lbs shipping