
And in my knowledge relay actually is controlled by it's transistor. >We usually use relay in automation wiring. # I was also wondering what was better, Relay or transistor output? # You can try the trial version of Keyence PLC software: I had gone through Keyence product cataloge and I found that Keyence PLC is quite unique! GX-ladder logic test software is good and advance, but i think it's slow when monitor mode is turn on. And also, Keyence simulator is fast and easy to use. However I prefer to use Keyence because it's so much faster when you try to debug on monitor mode. I am more familiar with Mitsubitshi GX-Developer. I personally like Keyence because it's so easy to program using it's software.

Our company mostly using Mitsubitshi and Allen Bradley PLCs but we do have a machine using Keyence.
