1.Precautions of using PLC transistor and relay
The PLC output is a common cathode output, the theoretical value is 1A, the actual use is less than 500mA, the COM wiring is negative, please use 24V voltage, there is no voltage output when it is used as a switch. If an external relay, the relay needs an external power supply.
The relay has a contact life, the theoretical value is 30W times, and the theoretical value of the external load does not exceed 5A. Frequently, the full load current may affect the service life, and there is no voltage out.
2.Precautions of Coolmay PLC output type selection
MT: indicates the transistor output, MR: indicates the relay output, and MRT: indicates the relay transistor mixed output.
The main differences between transistor output and relay output are:
(1)The difference in current load. At present, we use a transistor with a maximum current load of 500MA, and the maximum current load of the relay is 5A (the maximum relay current of the EX2N(S)/DX2N(S) series PLC is 3A);
(2)Output power: The transistor can only be connected to the DC24V power supply , and the relay can be connected to the DC24V and AC220V power supply ;
(3)Functional characteristics: If you need to send a pulse to drive a stepper motor, you should use the transistor output or the mixed output. Also if the output switch is active, it is recommended to use a transistor output;
(4)If both the relay and the transistor are available, it is recommended to use a transistor output because the transistor has no contact life limit and the lifetime will be longer than the relay as long as the current does not exceed the limit.