The AMPTEC 601ES Explosive Safety Digital Multimeter replaces the Dupont Blaster meter

Designed originally for U.S. Military/Defense system programs, (i.e. Air Launched Cruise Missile - Boeing Defense Systems ) to replace the aging and obsolete Dupont 101 Blaster meter. The AMPTEC 601ES Explosive Safety DMM features:  1) a ruggedized, water-resistant main front panel, 2) self-contained DC milliammeter (to independently verify it's USAF Munition Safety Board Approved failsafe "ohms" current source level,   3)  low level fail-safe voltage ( 50 mV) signal source , 4) fail-safe signal sources ( to independently verify unit's DMM stray voltage and stray current measurement function), 5)  4 wire Kelvin resistance or 2 wire "ohms" modes at the flip of a switch (silicone rubber boot protected),  6) standard DMM style gold plated 5-way binding posts ( accepts banana jacks, spade lugs, bare wires and other test lead connections, 7) wide viewing angle (tilted) ergonomic display - readable in direct sunlight,  8) separate battery compartment allows user to replace the unit's 4 ea. "AA" batteries without breaking the calibration seal, a shielded Faraday cage design for EMP , ESD protection, noise immunity, and more . 9) Only the AMPTEC 601ES Explosive Safety DMM has an independent on-board safety self check capability. Here is a Powerpointtm presentation of a complete AMPTEC 601ES DMM Safety Self-test or Checkout Procedure . It is an independent on-board safety self check for every function (stray voltage, stray current measurement and resistance) and every range on the DMM using the units' built-in milli-ammeter. 

The AMPTEC RESEARCH 601ES Explosive Safety DMM is designed for use in harsh environments (down to -0 °C) on the go “mobile” take it anywhere use, or for general purpose test bench use on ordnance. The unit's resistance measurement circuitry ( fail-safe current source) uses AMPTEC's proven USAF Munition Safety Board Approved Igniter Tester circuitry   ( AMPTEC 620A-4 Fail-Safe Igniter Tester) military programs.

Measure Stray Voltages from 600V to 0.1 mV  - Integrity of Measurement : Built-in Self-Test

The AMPTEC 601ES Explosive Safety DMM can safely measure Stray Voltage(s) at virtually all levels. It has a 600 VDC/RMS AC range or  200 VRMS, 20 VRMS and 2.0 VRMS (AC/DC) ranges with 4  1/2 digit resolution down to 0.1 mV DC/RMS AC. Stray AC/DC current can also be measured up to the 2.0 ampere DC/RMS AC level. The AMPTEC 601ES Safety DMM has a 5.0 ampere fast blow fuse that protects the AMPTEC 601ES Safety DMM from any overcurrent damage

Whenever the AMPTEC 601ES Safety DMM user wants to check stray voltage or stray current measurement functionality, self test signal sourcing ( small level voltage and current source) and is built-in. Completely isolated and separate from the unit's output terminals for safety reasons, the built-in 50 mV signal source self-test feature can internally provide 50 mV to the DMM electronics ( in voltage mode) to check/display basic stray voltage measurement functionality. In a similar fashion, a built-in 5 mA current source may be apply to cross check the DMM's stray current measurement functionality ( when in AC/DC Current mode) may also be selected.

Incredibly Safer than a commercial DMM

Commercial Multifunction DMM’s have many modes (i.e DC Voltage, AC Voltage, DC current, AC current, frequency, shift keys, Capacitance, some even with AC powered line cords and more.) that can accidentally fire igniter circuit. Just because a DMM may be battery powered, doesn't mean its "failsafe". A single "AA" battery such as the Duracell MN1500 Coppertoptm which has 1500 mAHr capacity ( 1.5Ampere Hours). This level is enough current to be extremely hazardous if its accidentally connected (i.e. component failure ~short) to a squib or EED (a lot of ignitors/squibs have a 1.0 ampere ALL FIRE current level). DMMs were not designed to fail in a safe mode.

Unlike a commercial DMM, you can see for yourself that the unit's resistance function is only sourcing < 5 mA ( a very safe level) into the unit's independent Simpson analog milliammeter just before preforming an ordnance test (0 to 10 mA ). More important, should there ever be a component failure in the AMPTEC 601ES Safety DMM, it has the life saving advantage of failing safe ( less than 8 mA worst case component failure).  The AMPTEC 601ES Safety DMM uses the USAF Munition Safety Board approved low level failsafe current source circuitry for all resistance measurement modes. The AMPTEC 601ES Explosive Safety DMM has many safety feature built-in to prevent virtually any hazardous failure mode.

All instruments eventually break or fail (need repair) sooner or later but are they designed to be failsafe like the AMPTEC 601ES DMM ?

Essentially, unlike a commercial DMM, if the AMPTEC 601ES DMM has an electrical fault it offers the life saving advantage of being failsafe. Commercial DMMs are not designed using the USAF Munition Safety Board Approved fail-safe current source circuitry found in the 601ES DMM. The  maximum output current with any single component failure is 8mA (well within the acceptable safety margin established by virtually all Explosive Safety Approval Boards). Virtually all commercial DMMs have lots of things that if they failed worst case - make them extremely hazardous to use on electrically fired explosive ignitiators and related ordnance. Commercial DMMs lack an insulating (oversprayed) polyurethane conformal coating on all the main PCB after the components are placed. The PCB conformal coating helps prevent an accidental loose wire, washer, or screw from conducting in a hazardous manner. 

For resistance measurement of missile warhead squibs, rocket motor squibs only AMPTEC's failsafe current source ( same as in all AMPTEC 620 and 630 series Igniter Testers) safety instrumentation is used by the USAF, US NAVY and US Army.  Most DMMs also aren't optimized for squib resistance measurements, most squibs are around 1.0 Ohm and the AMPTEC 601ES Explosive Digital Multimeter offers a 2.0 Ohm full scale range. For a data sheet of all the accessories, test leads, probes and options that are compatible with the AMPTEC 601ES DMM, 620A-4, 620BH, 620ES, 620GD, 620RK etc select here.

Commercial DMMs lack an independent on-board Simpson milliammeter (0 to 10 mA fullscale) the AMPTEC 601ES DDM has. It allows independent verification to the unit's output test current level checks just prior to making an ignitor/ordnance test. It is the ampere level that sets off squibs and EEDS. A 250 mA maximum "NO FIRE" current is common with squibs, above that level any thing can happen. The AMPTEC 601ES DMM  also has built-in signal sources to also check the stray voltage and stray current measurement  capability. It's called "measurement integrity" and "explosive safety assurance" and the AMPTEC 601ES Explosive Safety DMM was designed from the ground floor up to have both ("measurement integrity" and "explosive safety assurance" ).

The AMPTEC 601ES DMM internal packaging and impact resistant case is constructed to a water tight standard. The polypropylene case is water proof when closed (and purge valve is shut) to a depth of 3 feet. The AMPTEC 601ES Safety DMM also floats in water and can be operated outside in direct rain, as it has silicon boot seals over all switches. The waterproof front panel covers a unibody aluminum front plate mounted on a water-resistant compressed o-ring in bezel construction.  Internally the unit features an all metal Faraday Cage wired to the front panel chassis ground terminal for added noise immunity.

Polyurethane Epoxy Conformal Coated Circuit Board and More ...

A common question we get from safety committee engineers is "What sort of electrical and  mechanical  measures are taken with the AMPTEC 601ES Safety DMM 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 entire PCB (except for the calibration trim pots) is protected with a conformal coating ( non-conductive polyurethane epoxy )  to make it extremely difficult to get an accidental conductive pathway.  The AMPTEC 601ES Explosive Safety DMM fundamentally uses the USAF Non-Nuclear Safety Board approved AMPTEC 620A-4 Igniter Tester Failsafe current source circuitry.  The unit's 2.0 Ohm range which has also been approved by the US Dept. of Energy (High Explosive Safety Committee) in the form of the AMPTEC 630ES and AMPTEC 640SL as well as the intrinsically safer AMPTEC 620UK Safety Ohmmeter.  The ultimate electrical safety analysis for failsafe current relies on multiple backup components  using Ohm's 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.  The AMPTEC 601ES DMM circuit schematics are available upon request for reviewing a version's maximum failsafe current level.

Kelvin Clips , Probes and Test Lead Accessories