can any one explain ?

[ashraf]

help me to under stand  these instructions?

1) INI(61)     according to what i enter the values    P , C , P1

2)PRV(62)       P , C  ,D

3CTBL(63)           p , C ,TB

i know that first one according to plc type 

and  when i use them it must be an external input or what ?

[BITS N BYTES]

Which model PLC?

Then we can refer you to the applicable manual for those instructions.