ESD Strap & Station Calibration

Purpose

The purpose of this procedure is to establish guidelines for the calibration of areas that use Electrical Static Discharge (ESD) grounding straps & stations.

Scope

All areas that use ESD equipment will be certified by this procedure no less than every 12 months.

Procedure

All ESD stations must be certified at least once per year. In the case that an ESD mat is moved or new equipment is obtained, the proper ground connection is to be verified.

Preliminary Instructions and Notes

1. Read this entire procedure before beginning the calibration.
2. Visually examine the ESD workstation for any condition that could cause errors in the calibration.
3. If any of the requirements cannot be met, refer to the applicable manufacturer manual.
4. If a malfunction occurs or a defect is observed while calibration is in progress, the calibration shall be discontinued and necessary corrective action taken; if corrective action affects a measurement function previously calibrated, the function shall be recalibrated before the remainder of the procedure implemented.

Reference Material

Applicable Manufacturers Manual or Brochures.

Specifications

The specifications of the ESD workstation are determined by the applicable manufacturer's documentation. If the manufacturer's documentation is not available, then the specifications identified in this procedure are used.

Equipment Required

The Standards listed below should be selected on the basis of their higher accuracy level when compared to the unit under test. Equivalent Standards must be equal to or better than the Minimum-Use-Specification.

• Digital Ohm Meter
• Surface Resistance Test Kit (SRT Kit)

Detailed Procedure

Physical Inspection of ESD Workstation

Inspection will be made to prevent the ESD mat surface from being incorrectly connected in series to its common ground.

1. Verify that each ESD station is electrically isolated from direct ground. Check that there is only a one 1 meg-ohm resistor for each 6 feet of ESD matting.
2. Visually ensure that each of the 1 meg-ohm resistor(s) have connecting ground wire (as in the case above) leading from the ESD mat surface to a common earth ground.
3. Verify all wires are in good physical condition.

Grounding Strap Test with Ohm Meter

1. Measure between the earth ground and wire connected to the ESD mat, at the point where the wire actually connects to the mat. The reading should indicate approximately 1 meg-ohm ±10%.
2. Disconnect the wrist strap cable(s) from the ESD station connector and verify the grounding wrist strap's 1 meg-ohm resistor ±10%.
3. Electrically ensure that the station and the connecting grounding straps ALL have a common earth ground.

Surface Resistance Test

1. Inspect the workstation's ESD mat for excessive wear and replace if necessary. Clean the ESD mat with an approved cleaner such as "REZTORE" prior to testing.
2. First, test the SRT kit meter by setting the slide switch to the "Battery Check" position and pressing [TEST]. The battery check scale is identified with the letter "B." If the pointer remains in the red portion of that scale replace batteries before continuing.
3. Connect the leads to the black and red terminals on the meter, and the other ends into the holes on top of the heavy electrodes.
4. Set the meter's slide switch to "10 Volt Test." Place the heavy electrodes on the ESD mat in opposing areas and press [TEST]. Set the meter on "HOLD" by flipping up the metal tab.
5. Wait 15 seconds for a clear reading on the scale before moving on to the next point. A reading between 1 x 10x6 and 1 x 10x10 is required at a minimum of 5 sets of locations on the mat.

Surface-to-Ground Test

1. Connect the meter's red terminal (marked LINE) lead to one of the heavy electrodes and the meter's black terminal (marked EARTH) lead of the meter to grounding clip and attach to a groundable point on the ESD material. Set the meter again to the "10 Volt Test" position, press [TEST], and set the meter on "HOLD" by flipping up the metal tab.
2. Wait 15 seconds for a clear reading on the scale, before moving on to the next point. A reading between 1 x 10x6 and 1 x 10x10 is required at a minimum of 5 locations from the mat to the ground.
3. Record a "pass" or "fail" in the "SGT" column on the ESD Station Certification Record (FRM-1145). Flip "HOLD" tab off to end test.

Reason for Reissue

Revision A - First Release