I have done some considerable reading here regarding the use of timers and have decided to use the IEC timer (SFB4) instead of the standard on delay timer. I have pressed the F1 key and it was informative on how it works and what each in and out variable is used for. I believe I understand its use and I should have no trouble with using this instruction (function).
The issue I am having is the symbol. When using a standard timer I simply assign T0 - T255 and all is well. What type of symbol do I use for this block? On my 315-2 PN/DP I am only allowed so many timers and T321 gives me an error on download.
Please note that this is my first 'from scratch' Siemens project so consider me a newbie with Step 7 (v5.5). Any simple bits of information that you can offer me will be helpful and appreciated.
Thanks.
The issue I am having is the symbol. When using a standard timer I simply assign T0 - T255 and all is well. What type of symbol do I use for this block? On my 315-2 PN/DP I am only allowed so many timers and T321 gives me an error on download.
Please note that this is my first 'from scratch' Siemens project so consider me a newbie with Step 7 (v5.5). Any simple bits of information that you can offer me will be helpful and appreciated.
Thanks.