Using Fiber Cams for timing and positioning......

The use of Cams is very common and easy for the positioning and timing setting for a moving shaft. It is the manual and the cheapest method for this application instead of using the digital shaft encoder. For Example if we look at the example of Packing machine when we want to sense the blank faulty packet of the soap on a specific angle or position of the shaft. Then we have to use encoder for this application i.e when the shaft is on at that angle the sensor sense the packet at that time only of that specific angle or position.

So, for this purpose we use encoder but if the timing is much more i.e 5 or 6 we can easily use a fiber cams for setting up the timing instead of a encoder. The main advantage is also that we can use the fiber cam with normal sensor i.e metal detector and can easily be connected with the normal input of the PLC, there is no need of any High speed input or High speed counter for the software to use this.

Well, the parameters used for the above mentioned setup for the plc program will that the sensor of the Cam will be our INBIT and the sensor of the fault i.e packet sensor will be the DATA BIT and then the both will generate the pulse at the same time the plc will start counting and will reject the packet at required counting of the shaft from the cam. For this, we use SHRB function in Siemens step 7 PLCs. The program example for this is also given below.