Chamberlain K001A5729, Manual

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When shopping for a meter, look for a meter able to fi t in a shirt pocket or clip on a belt. A meter with an audio signal
(buzzer) for continuity checks is recommended.
Checking Ohms/Continuity
When checking the operation of a switch, select the ohm mode on multimeter. (The ohm symbol is Ω). Make sure the
test leads are plugged into the correct sockets for reading ohms. If there is more than one setting in the ohm section
of the meter, select the one with the audio signal.
To test a limit switch, connect one test lead to the Common prong and the other to the Normally Closed prong. The
meter should read 0 resistance or very low resistance. The electricity is fl owing from the Common prong to the
Normally Closed prong. This demonstrates continuity. Activate the switch, the meter will read infi nite resistance or no
continuity. The wires inside the switch are no longer touching between the Common prong and the Normally Closed
prong.
Move the test lead from Normally Closed to Normally Open. While the activation arm is not pressed, the meter should
read open circuit, demonstrating no continuity. Activating the arm should read 0 resistance, demonstrating continuity.
The procedure is called a “Continuity Check” and is used to check for a continuous fl ow of electricity.
Checking Voltage
A multimeter may have several settings for checking voltages. The number associated with each setting is the
maximum voltage able to be read. A meter may be damaged if connected to a higher voltage than selected. Either AC
or DC must be selected prior to testing any circuit. AC stands for alternating current and DC stands for direct current.
AC is usually the incoming line voltage, i.e. 115VAC, 460VAC and so on. 24VAC is also found in the control circuit of a
commercial operator. DC is usually a power source from a battery or the control voltage in a logic board.
Set the meter to VOLTS AC at the lowest setting which is still higher than the expected voltage. If 115VAC is expected
and the meter has 10VAC, 50VAC, 250VAC and 1000VAC, turn the dial to 250VAC. Some meters have only one VAC
choice and the meter can automatically adjust for the voltage received (auto scaling).
D
Basic Electrical Information
Multimeter
AC DC