verification process for SURPA 518-2 Wrist strap Monitor

The SURPA 518-2 is a dual-port continuous monitor designed to ensure that two operators are properly grounded in real-time. Because these units are used for technical compliance in cleanrooms and ESD-sensitive areas, periodic verification is essential to ensure the alarm thresholds remain accurate.

Here is the standard verification and "debugging" process for the SURPA 518-2:

Before formal verification, the unit must be properly grounded and powered.

1. Connect the AC transformer (9V output).
2. Ensure the grounding wire is securely attached to a verified ESD ground point.
3. There is typically a small "trim" adjustment (potentiometer) accessible via a small hole on the unit.

• Insert a standard wrist strap with a 1M\Omega resistor into the jack.
• Wear the strap to complete the circuit.
• If the red light/alarm is active while the strap is properly worn, use a small flat-blade screwdriver to turn the adjustment counter-clockwise until the green light stays solid.

To verify the unit's accuracy (2M\Omega +- 5%), you should use a decade resistance box or a dedicated ESD calibration unit to simulate the operator's resistance.

Steps:

• Connect the resistance box to the Wrist Strap Jack on the 518-2.
• Set the resistance to 1.0M\Omega. The monitor should show a Green LED.
• Slowly increase the resistance. The monitor should trigger a Red LED and Audible Alarm when the resistance exceeds approximately 2M\Omega (the factory threshold).
• Repeat the process for the second port to ensure both channels are functioning independently.

For daily operational checks (common in ISO-certified environments), perform the following:

1. Connection Test: Unplug the wrist strap from the monitor while it is turned on. The monitor must immediately trigger the audible alarm and red light.
2. Skin Contact Test: With the strap plugged in but not worn, the alarm should sound. Once placed firmly on the wrist, the light should switch to green.
3. Visual Inspection: Check the power cord and ground wire for any fraying or loose connections that could cause intermittent "ghost" alarms.