# Limit drive starts with function block diagram

I have a drive (modulating fan) which needs to be interlocked and prevented from starting. The requirement is that:

The drive is limited to 3 starts per hour with a minimum of 10 minutes between starts.

I am programming using function blocks diagrams. Some information to aid in your understanding of the function block diagram I created:

• Program flow follows the execution numbers on the function blocks
• Cyan lines show values of the integer short data type
• Black lines show binary values (0/1)
• References (small rounded rectangles with an alphanumeric identifier and no execution number) are used to move data without the need for connecting lines

Many of the blocks used are self-explanatory, however, the following information may be of use:

• diss function block - routes either in1 or in2 to out depending on bse. When bse equals 0, in1 is used
• ccob/ccos depends on the mode. 1 = rising edge, 2 = falling edge
• dvss function block - outputs the min/max of the two inputs

Here is the function block diagram. I am interested in an alternate or more efficient methods to achieve the requirement.

I have exported my loop diagram as an SVG.

I have broken the function block diagram into three views:

• Did you program this into a PLC, or is this an unproven design? – Mast Sep 13 '17 at 6:57
• @Mast Yes, function block diagrams are developed and downloaded into PLCs. The code works as per the requirement. – xvk3 Sep 13 '17 at 7:42
• Can you include the SVG into the question itself? As per the requirements for Code Review, at least the important parts of the code must be present in the question itself. Links can be used as support, but links shouldn't have to be followed to review the essence of the question. – Mast Sep 13 '17 at 9:16
• @Mast SE doesn't accept displaying SVGs in the question body. "Failed to upload; not a valid image (jpeg, png, tiff, gif or bmp)". – xvk3 Sep 13 '17 at 9:19
• @Will you can use the SVG image in the question if you post it on a HTTPS enabled site. After doing this, you can get the raw url, http://svgshare.com/s/306.svg, and can include it in the question by adding [![][0]][0], followed with [0]: url at some point after it. With the current url it'd be [0]: http://svgshare.com/s/306.svg. Which doesn't work as svgshare doesn't allow HTTPS traffic. – Peilonrayz Sep 13 '17 at 12:21