ABB AX400 Series User Manual

Also see for AnalyzeIT AX460: User guide User guide Manual User guide User guide

Contents

ABB AX400 Series User Manual Manual pdf 50 page image

Single and dual input analyzers for pH/Redox (ORP)AX416, AX436, AX460, AX466 & AX468 6 Installation48 IM/AX4PH Rev. P6.3.1 Relay Contact Protection and Interference SuppressionIf the relays are used to switch loads on and off, the relay contacts can become eroded due to arcing. Arcing also generates radiofrequency interference (RFI) which can result in analyzer malfunctions and incorrect readings. To minimize the effects of RFI, arcsuppression components are required; resistor/capacitor networks for AC applications or diodes for DC applications. Thesecomponents must be connected across the load – see Fig. 6.6.For AC applications the value of the resistor/capacitor network depends on the load current and inductance that is switched. Initially,fit a 100R/0.022 μF RC suppressor unit (part no. B9303) as shown in Fig. 6.6A. If the analyzer malfunctions (locks up, display goesblank, resets etc.) the value of the RC network is too low for suppression and an alternative value must be used. If the correct valuecannot be obtained, contact the manufacturer of the switched device for details on the RC unit required.For DC applications fit a diode as shown in Fig. 6.6B. For general applications use an IN5406 type (600 V peak inverse voltage at3 A).Note. For reliable switching the minimum voltage must be greater than 12V and the minimum current greater than 100mA.Fig. 6.6 Relay Contact Protection&> > &A$> 9 ? >&> > &A$> + ? >,// //