5 Application Examples100 Keysight U1401B User’s and Service GuideSimulation Mode for mA OutputIn simulation mode, the instrument simulates a current loop transmitter. Use thissimulation mode when an external DC 24 V or 12 V supply is in series with thecurrent loop being tested. Always use the special yellow test lead. Follow theprocedure below when performing mA output simulation.1 Turn the rotary switch to any one of the / or /positions.2 Connect the special yellow test lead between the positive output terminal ofthe instrument and the positive terminal of the measurement device on thecurrent loop. Refer to Figure 5-2 on page 101.3 Connect the black alligator lead between the COM terminal of the loop sourceand the negative terminal of the measurement device on the current loop.4 Connect the red alligator lead between the negative output terminal of theinstrument and the positive terminal of the current loop source. Make sure thepolarity is correct.5 Set the current level of the calibrator between 0 mA and 20 mA. Do not set anegative current output value.6 Press OUTPUT to output the test current.This connection can be used for any loop voltage from 12 V to 30 V.CAUTION Always use the supplied special yellow test lead to perform mA simulation.Disconnect the test lead from the current loop before turning the rotaryswitch to change function or to power-off this instrument. Failure to do sowill result in a current of at least 16 mA in the 250 Ω load connected loop.
