Where MR Is the relay type and MT is the transistor type. Their differences are as follows:
1. The external power supply connected to the relay can be DC or AC, which can directly drive 220v DC load. The external power supply of the transistor can only be connected to DC, which can not directly drive the switch
2. The switching frequency of relay type is low, and the transistor can output high frequency signals such as the pulse output of servo system using transistor type PLC. In practical application according to the need to choose the corresponding PLC specifications.
2PLC output terminal
Output terminal introduction
In the example of 40 terminals, input 3 groups + output 2 groups =5*40 terminals. The input terminal has only one common terminal S/S, while the output terminal has five common terminals. Y0 and Y1 use com terminals separately, Y2 and Y3 share con2, Y4, 5, 6 and 7 share com3, Y10, 11, 12 and 13 share com4, and Y14, 15, 16 and 17 share com5.
3 Relay wiring
The PLC output circuit of relay type is shown in the figure below. Dc power and AC power can be used to drive the load, regardless of leak-source output.
Relay type PLC output loop
The common output control in industrial control includes motor, indicator light, alarm, electromagnetic valve, etc., one can be directly connected with PLC output terminal Y, and some need intermediate relay or contactor to connect.