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.cMaintenance and troubleshootingMeasuring the voltage drop in a <strong>DALI</strong> circuitProceed as follows:Check that all the <strong>DALI</strong> devices are functioning properly.Make sure there is no communication on the <strong>DALI</strong> line.Measure the voltage at the <strong>DALI</strong> power supply.» The value must be between 11.5 V and 22.5 V; a typical value is 16 V.» A much lower value may indicate a short-circuit.Measure the voltage at the <strong>DALI</strong> device furthest from the <strong>DALI</strong> power supply.» The value must be between 9.5 V and 20.5 V.» A much lower value indicates that there is a short-circuit somewhere.Create a short-circuit between DA and DA at the <strong>DALI</strong> device furthest from the <strong>DALI</strong> power supply.Measure the voltage at the <strong>DALI</strong> power supply.» The value that you measure is the <strong>DALI</strong> voltage drop.» This value must not be higher than 2 V.» If it is higher than 2 V, check whether any of the following have occurred:» The <strong>DALI</strong> line is too long (more than 300 m at 1.5 mm2)» The cross-section is too small» High contact resistance» The value must be brought down below 2 V.Remove the short-circuit between DA and DA on the <strong>DALI</strong> device furthest from the <strong>DALI</strong> power supply.Possible solution: <strong>DALI</strong> RepeaterIf the voltage drop is greater than 2 V, a possible solution is to use a <strong>DALI</strong> RepeaterA <strong>DALI</strong> Repeater is not the right answer in every situation; its use depends to a large extent on the wiring. First, thewiring of the <strong>DALI</strong> circuit must be checked. This solution should only be used if no other solution is practical. Above all,you must find out why the system has not been working properly up to now. Make sure that you will not be faced withthe same problem again.A <strong>DALI</strong> Repeater can helpIf the <strong>DALI</strong> cable is longer than 300 m with a cross-section of 1.5 mm2.If the cross-section is too small.½ CAUTIONPlease read the data sheet carefully before using a <strong>DALI</strong> repeater.Example: <strong>DALI</strong> circuit with a voltage drop greater than 2 VIn this example the <strong>DALI</strong> voltage drop is well above the limit of 2 V. The <strong>DALI</strong> line is too long.It is 470 m instead of the permitted 300 m.<strong>DALI</strong> Manual | 08-2013 | en83 / 93