Ladder logic for the Siemens S7 processor

Screen shots from the Step 7 software of the ladder logic.

Ladder logic program for the Siemens S7 plc in the beer bottling line 1plc.mwp

To open this file you need to use the Demo version of the Siemens STEP 7-Micro/WIN software which will only work with Windows XP and Windows 2000 (it does not work with Windows 7)

Fill head does not move up and down smoothly

If the the fill heads do not drop down smoothly.

It may be that the guide block is loose.

If the block that guides the fill head moves up and down (see photo) - it can cause the fill head to not drop smoothly.

You can tighten this block by removing the V-handle and tighten the retaing nut.

Wiring the Beer In Valve for CIP

The Beer in Valve is controlled by the float valve. Once the float says that the bowl is full the Beer in Valve is closed.

To keep the valve open while running cleaning solution through the machine - you need to keep the Beer in Valve open.

The beer valve is tied to the Siemens processor through o1.0. You will find o1.0 (or 1.0) down on the terminal strip in the bottom of the control cabinet.

For the switch I used a SPDT switch with (3) terminals. Mounting it in the wire tray cover on the far right (doesn't show up in the picture)

Move the wire coming in from the beer valve at o1.0 - over two places to an empty terminal.

Connect the center terminal of the switch - to the new Beer in Valve terminal.

Connect one of the other switch terminals to the original o1.0 terminal that goes to the processor.

The third switch terminal is connected to the +24VDC supply.

In one position the Beer in Valve would be tied the usual circuitry and be controlled by the float switch.

In the other position the Beer in Valve is 'tied high' causing the beer valve to be open for CIP cleaning.