Using timers would give you the most flexibility. Using the forum search would deliver results.

You can find a library of general functions if you use the search facility. Therein is a pulse generator function. -- assuming you have the right software version and CPU.

Alternatively the following code idea can be adapted to various outputs from a fixed clock input. As coded the code block below delivers the same output rate as the input clock rate.

If you want a super low CPU intensive approach, use edge (P-TRIG & N-TRIG) and ADD to count up to 2/3/5 with the 1-sec system clock signal.

When the ADD result becomes 2, Toggle the 2s clock.  Then reset the 2s count to 0.  Repeat this forever.

Do the same for _any_ clock by converting the above into an FB where the # of seconds is an input parameter, and the output is that clock's current state (on/off).

Call each unique # of seconds once early on in OB1 (or your lowest cyclic OB #) so it is available throughout the PLC logic. 

You might assign each FB's output to a Global DB tag for ease of use - rather than "FB instance DB name".Q. 

Maybe something like this:

• "Clock".2s
• "Clock".3s
• "Clock".5s

Where: "Clock" is the global DB name.

I call this using the PLC's capabilities to your own advantage.

AutoGen_2558162

Hi,
I’m using the system bit Clock_0.5Hz (BOOL). It works fine to blink a lamp every second, but now I want to create other time tags from it: 2s, 3s, 5s, etc.

I first tried usingMULwith the BOOL, but of course that doesn’t work. What is the right way in TIA Portal to generate these longer pulses from the 0.5Hz clock?

Thanks for any tips (LAD/SCL examples welcome).

 

Put the ADD right after the P_TRIG.  That will generate one addition per clock transition from low to high.

As a matter of using the correct instruction to add 1, replace the ADD with INC.  It increments by 1 each time it is executed. 

To check if the time ticker (counter) has reached the value of 2, use the ---|==|--- comparison instruction (LAD).  You should scan through the available instructions before posting so you can find all this on your own.  I am not here to teach people.  I don't get paid enough as a forum volunteer to do that.

AutoGen_2558162

 Here’s the LAD I tried (see screenshot attached). Did I understand correctly? I increment the counter with the 1-s tick, but I’m not sure how exactly to toggle the 2s clock and then reset the counter when it reaches 2.

As you can see values for the clocks are in units of frequency. So, to get longer periods you should divide.

:P

AutoGen_2558162

I’m using the system bit Clock_0.5Hz (BOOL). It works fine to blink a lamp every second, but now I want to create other time tags from it: 2s, 3s, 5s, etc.

I first tried using MUL with the BOOL, but of course that doesn’t work. What is the right way in TIA Portal to generate these longer pulses from the 0.5Hz clock?

AutoGen_2558162

Hi, thanks for your input.

In your example, what exactly is #pattern.%X0 ? Where does it come from, and what type of tag is it supposed to be?

See the declaration of #pattern in the parameters of the FB. It is a WORD type. Notice the predefined bit pattern.

The rotate instruction used is aimed for a WORD. A DWORD rotate can be used if #pattern is declared as a DWORD.

The .%X0 part is a technique called "address slicing"; available on the S7-1200 and S7-1500. It is documented in the system manual, in-software help and on SiePortal. See: [LINK: How can you access unstructured data types bit-by-bit, byte-by-byte or word-by-word and symbolically in STEP 7 (TIA Portal)?]