ABB AK101 User Manual

ABB AK101 User Manual Manual pdf 27 page image

256.3 Electrical ChecksCarry out the electrical checks detailed in Sections 6.3.1 and6.3.2.6.3.1 Power Supply Unit OutputWarning. This unit is part of the certified intrinsicallysafe system. Appropriate safety precautions must betaken to prevent any incendive electrical discharges inthe hazardous area when carrying out this task.Testing the output may only be carried out with thehazardous area cable disconnected.1) Electrically isolate the PSU.2) Remove the cover from the PSU.3) Disconnect the output wires to the hazardous area atterminals TB2+ and TB2–.Warning. Ensure that proper electrical safetyprecautions are taken at all times when undertaking thisprocedure.4) Switch on the PSU and check that the output measures350mA into a 14 load.5) On completion of tests isolate the unit and reconnect theoutput wires to the hazardous area.6) Replace the cover on the unit.6.3.2 Zener Diode Safety Barrier DevicesZener diode safety barrier devices are fitted to the katharometersystem as detailed in Table 6.1 and are checked at the time ofmanufacture. To ensure absolute safety, check that the barriersare correctly earthed by carrying out an appropriate test beforeusing the katharometer system.Warning .• The zener diode safety barrier devices are certifiedintrinsically safe and form part of the certifiedintrinsically safe system. Appropriate safetyprecautions MUST be taken to prevent anyincendive electrical discharges in the hazardousarea when testing the barriers.• If the tests identify a faulty barrier, it MUST bereplaced by a new unit OF THE SAME TYPE – seeTable 6.1. The barriers are sealed units and repairsARE NOT permitted.6 SETTING UPTable 6.1 Zener Diode Safety Barriers6.3.3 Checking Intrinsically Safe EarthCheck that the resistance between the earth terminalconnecting zener barriers in the 6553 Display Unit and theapplication plant system high integrity earth does not exceed0.1 . Also check the low flow alarm zener barrier (if fitted in thecubicle) and the application plant system high integrity earthdoes not exceed 0.1 .epytreirraB noitacoLXETAotsmrofnoCCE/49/9evitceriDrebmunetacifitrecca5577LTM tinUyalpsiD3556 dna7127XETA10SAB5200.40SABxECEI+767LTMmralawolfwoLnihtiw)dettiffi(elcibuc2027XETA10SAB dna9100.50SABxECEI