① When an external signal is input, one pulse is applied in synchronization with it. Example: If external signals are input 5 times at 1-second intervals, a total of 5 pulses are applied, one every second.
② There is an error in the INS-S220 instruction manual, and external synchronization can be operated at a 1ms period at voltages of 0.99V or less. When used at 1.0kV or higher, the synchronization period must be 10ms or more. (As stated on the specifications page of the instruction manual.) When used at 1.0kV or higher, signals with a period of less than 10ms are ignored. If an external signal is input at a 7ms period, for example, the behavior is: 0ms (1st time): pulse is output; 7ms: not output; 14ms: output; 21ms: not output. *At 0.99kV or less as well, signals with a period of less than 1ms are ignored.
③ There is a delay time, but because output is performed by software control, there is no specified fixed delay time.
[Reference] In the case of the mercury type, there is no function that ignores pulses below a certain ms period. However, because the response time for mercury relay ON takes several ms, in practical terms it does not respond to signals with a short pulse period. For signals that are right on the edge of whether they respond or not, it is possible that output may or may not occur, so the operating period stated in the instruction manual (4020: 10ms, 4040: 16ms) is required.