testing

Reliable performance of ESD matting and ESD wrist straps is critical for your product’s integrity and reliability. But the hand testing and hand logging of wrist straps and tabletop material performance that is required is a cumbersome, labor-intensive paperwork nightmare. Use of our ESD wrist strap and ESD bench mat monitors continuously verifies the effectiveness of your ESD protected workstation, simultaneously satisfies ISO logging requirements and insures outstanding product quality.

Operators plug their ESD coil cord into the grounding jack of the constant monitor right at their workstation. The constant monitor grounds the wrist strap and simultaneously monitors for faults in the ground path from the strap to the earth ground, including proper contact with the operators skin. A proper working ground path results in the LED on the constant monitor to glow green (indicating GOOD). If a fault is detected, the LED will blink red (indicating FAULT), and the unit will repeatedly beep.

Types of Constant Monitors

Capacitance (or single wire) constant monitors
This type of monitor is simplest and most cost-effective constant monitor. When a person is wearing the single wire wrist strap the monitor detects the person and puts the monitor in the unalarmed state. The monitor circuit detects a person (a conductive object) and its relationship to ground (another conductive object).  View our Capacitance Monitors.

Impedance (or single wire) constant monitors
The impedance monitor uses a detection circuit designed to reduce false alarms and eliminate adjustments. It uses the phase difference between current and voltage to detect changes in impedance of the cord, band and person. A very low AC voltage is used for constant sensing. Any standard wristband and coiled cord can be used.

Resistance (or Dual Wire) constant monitors
This type of monitor is used with a two wire (dual conductor) wrist strap. When a person is wearing a wrist strap, the monitor observes the resistance of the loop, consisting of a wire, a person, a wristband, and a second wire. If any part of the loop should open (become disconnected or have out of limit resistance), the circuit will go into the alarm state. An important feature of the Dual Wire Wrist Strap is that even if one conductor is severed, the operator has reliable path-to-ground with other wire.  View our Resistance Monitors.

Over the past year, Transforming Technologies has worked diligently to create a line of dual conductor grounding products that is competitive in design and value to 3M’s dual line.   Recently our CC3000 Series Dual Conductor Coil Cords were put through an independent test by Affinity Static Control Consulting. Below is an excerpt from their test results.

Introduction:
Tom Watkins of Transforming Technologies, LLC., contacted David E. Swenson of Affinity Static Control Consulting, LLC (Affinity) regarding testing of dual conductor wrist strap cords according to ANSI/ESD S1.1 – Wrist Straps, for flex life. The aforementioned Standard requires a minimum of 16,000 cycles through 120 degrees of rotational Arc while under tension of 1 pound on the cord under test.
Specifications:
Standard 1.1 requires that the minimum life of all samples tested have a flex life of at least 8,000 cycles and that the average of all samples exceed 16,000 cycles. Flex life failure includes an increase in electrical resistance exceeding 25% of the rated resistance value or any evidence of strain relief or cord jacket failure. In the case of the dual conductor cords tested, there is a 1 megohm resistor in each of the conductors installed in the wires at the wrist strap plug end of the cord. The cord continuity is from barrel to barrel and from tip to tip of the modified phono-jack type connectors with an expected resistance of 0.9 kohms to 1.1 megohms. The test apparatus has a capability of testing two cords at one time at a rate of 2220 cycles per hour.

Test Results:
Samples were selected at random from the set of 10 received cords for testing and placed on the tester 2 at a time, starting with the wrist strap plug end first. All the samples tested survived well past the 16,000 cycles required by Standard S1.1. No evidence of strain relief cracking or electrical change was noted on either end of the dual conductor cords until much higher cycle times. The cords, as tested, meet the requirements of S1.1 with regards to strain relief integrity.

Summary:
The dual conductor cords provided by Transforming Technologies, LLC for qualification testing meet and exceed the requirements for flex life established in ANSI/ESD S1.1 – Wrist Straps.  The full report from Affinity can be found here.