Desco Combo Tester X3 Technology
• The solid-state touch test switch maintains test accuracy and extends the lifetime of the tester
• The 30 volt test signal increases test reliability
• Pairs with the EMIT 50755 ESD Glove Test Fixture to test operators that wear ESD gloves or finger cots
per Compliance Verification required by ESD TR53 The factory test limits are set to:
Wrist Straps: 750 kilohms and 10 megohms Footwear: 750 kilohms and 35 megohms (See page 3 for alternate test limit settings)
Per ANSI/ESD S20.20 section 7.3 “A Compliance Verification Plan shall be established to ensure the Organization’s fulfillment of the technical requirements of the ESD Control Program Plan. Process monitoring (measurements) shall be conducted in accordance with a Compliance Verification Plan that identifies the technical requirements to be verified, the measurement limits and the frequency at which those verifications shall occur. The Compliance Verification Plan shall document the test methods and equipment used for process monitoring and measurements. … The test equipment selected shall be capable of making the measurements defined in the Compliance Verification Plan.”
Per ANSI/ESD S1.1 Annex A.3 Frequency of System Testing “The wrist strap system should be tested daily to ensure proper electrical resistance.”
“Compliance verification should be performed prior to each use (daily, shift change, etc.). The accumulation of insulative materials may increase the foot grounder system resistance. If foot grounders are worn outside the ESD protected area testing for functionality before reentry to the ESD protected area should be considered.” (ESD SP9.2 APPENDIX B - Foot Grounder Usage Guidance)
Calibration
The Combo Tester X3 is calibrated to standards traceable to NIST. Frequency of recalibration should be based on the critical nature of those ESD sensitive items handled and the risk of failure for the ESD protective equipment and materials. In general, we recommend that calibration be performed annually.
The accuracy of the Combo Tester X3 is specified as:±20 % for 1 gigohm footwear test limit ±10 % for all other test limits
A periodic check using a precision resistance box can be used to verify proper operation.
The EMIT 50424 Limit Comparator is available for the convenient calibration of the Combo Tester X3.The Limit Comparator allows the customer to perform NIST traceable calibration on the Combo Tester X3. The Limit Comparator can be used on the shop floor within a few minutes, virtually eliminating downtime, verifying that the Combo Tester X3 is operating within tolerances. See TB-6581 for more information.
