Chapter 6 Electromechan e r m m c a a ni cal a S Sy s st ems e s 151 Copyright Goodheart-Willcox Co., Inc. Copyright Goodheart-Willcox Co., Inc. 4. Adjust the dc power supply to 15 volts. Set the indicator to a starting position and mark it as the starting reference. Then turn on the switch combinations for Step 1 of the full-step mode. Goodheart-Willcox Publisher DC stepping motor test circuit and stepping tables. – + – 5 3 4 1 2 DC stepping motor Red White Green Green/white Red/white 1000 Ω D4 D3 D2 D1 SW1 SW3 SW4 SW2 50 Ω 20 W 0-25 V Four-step input (full-step mode) Step SW1 SW2 SW3 SW4 W 1 On Off On Off 2 On Off Off On 3 Off On Off On 4 Off On On Off 1 On Off On Off Eight-step input (half-step mode) g Step SW1 SW2 SW3 SW4 W 1 On Off On Off 2 On Off Off Off 3 On Off Off On 4 Off Off Off On 5 Off On Off On 6 Off On Off Off 7 Off On On Off 8 Off Off On Off 1 On Off On Off 5. Go to the next switching combination indicated by Step 2 of the chart. Each combination will produce a rotary step. 6. Follow the stepping procedure through at least two of the four-step cycles. Notice that the switching step combination repeats itself after Step 4. 7. Mark the indicator location as the stopping position for reference. 8. Calculate the rotational degrees by multiplying the number of steps by 1.8. 9. If a protractor is available, measure the number of degrees of rotation between the starting indicator mark and the last switching location mark of the motor shaft. 10. Repeat the procedure outlined in Steps 2 through 9 of this activity for the eight-step sequence. In this stepping mode, each step produces 0.9° of rotation. 11. Disconnect the circuit and return all components to the storage area.