Fixed-time-limit polarity tester

The invention provides a definite time limit polarity tester, which is used for carrying out polarity test on a plurality of devices to be tested in a plurality of test loops, and comprises a programmable logic controller and a test waveform output module, the programmable logic controller determines delay information between each cycle test corresponding to each piece of to-be-tested device information according to the acquired information of a plurality of to-be-tested devices, and according to the delay information between each cycle test corresponding to each piece of to-be-tested device information, when a test condition of a certain to-be-tested device is met, the to-be-tested device is tested according to the delay information between each cycle test corresponding to each piece of to-be-tested device information. According to the method, the device to be tested is controlled to carry out cycle test, each test pulse signal generated by the device to be tested is output to the waveform output module, and