Measure the voltage at the first DC field device's + and - connections (screw terminals 9 and 10). The voltage at these points should match the input voltage.
Slide the switch labeled Test 1 down to toggle it and then measure the voltage at the DC field device's + and - connections (screw terminals 9 and 10). The voltage at these points should be 0 when toggled. Release the toggle and re-measure the voltage.
Slide the switch labeled Test 2 down to toggle it and then measure the voltage at the DC field device's + and - connections (screw terminals 9 and 10). The voltage at these points should be 0 when toggled. Release the toggle and re-measure the voltage.
Slide the switch labeled Test 3 down to toggle it and then measure the voltage at the DC field device's + and - connections (screw terminals 9 and 10). The voltage at these points should be 0 when toggled. Release the toggle and re-measure the voltage.
If you have a second DC field device, perform steps 1-4 by measuring the voltage at pins 11 and 12.