Belt scale, conveyors & Silos

[grnick50]

Hello all,

I have to write a piece of software (S7-300) for the following:
A crusher feeds a conveyor which in turn feeds a system of moving conveyors to fill silos. The position of the conveyors is known using limit switches, therefore the information of which silo is being filled is known.
The task is to determine how much goes in which silo.
In the past we did this by making totalizers for each silo. Using the active silo information and the pulse from the belt scale, the totalizer incremented the quantity of each silo.

In this new project the beltscale is connected to the PLC using Profibus-DP. The information I have available is not a pulse but the beltscale running total.
Do you have a recomendation on how to achive the above explained functionality (the one with pulse)?

Regards

 

[Lancie1]

1. At the start of a Silo filling, save the BeltScale Running Total (Begin) for later use. Then the amount in the Silo 1 at any time is:

Silo 1 Total = Old Silo 1 Total + BeltScale Running Total (Current) - BeltScale Running Total (Begin).

 

[grnick50]

How would you handle it when the running total rolls over.

 

[Lancie1]

You probably need to set up some way to plan for the rollover. When the Running Total approaches the rollover point (but before it reaches the roll-over point), save the current Running Total, then manually force a roll-over reset, and then make adjustments to all variables that are affected.