loss in weight

Hi,

I've been looking for a good S7 5.5 program for loss i weight system. I have two bins. They both have a rotary feeder. This bin will be used for mixing using ratio control. One of the bin has load cells giving me 4-20mA. I need to get the loss in weight to measure the flow rate of one bin. Please help

If a very high level of accuracy is not required then one way to calculate loss in weight would be as follows:

thank you,

the question is after one minute the process value from the 4-40mA will be moved to the register. So the value on the register where i moved the value will be the same as the process value every one minute and the difference will be Zero? am I right?
I was thinking on getting the value and move it to a register so that it will become previous and subtract it to a new value after a span of time? I just dont know how to do it?

Thanks for your help, maybe i,m not getting your instructions right please help me on this

You have to first decide what you want to use as your reference.

If you just want total loss in weight from initial value just move the value to the register in the beginning once and then subtract the current values from that to get the updated loss in weight every I/O scan.

But my method was if you wanted the rate of loss in weight.Then for only for one scan every time period that you set, you will get the value as 0 and from the next scan itself you will get the loss since the last move execution.

But you can even avoid this 0 by using a logic similar to this:

|              T1

|   M       +------+

|--|/|------| TON  |

|           | 1sec |

|           +------+

|

|  

|  T1       +--------+

|--| |---+--| MOV    |

|        |  | ip to  | 

|        |  |Rgstr   | 

|        |  +--------+ 

|        |             

|        |      M     

|        +-----(S)----

|

|              T2

|   M       +------+

|--| |------| TON  |

|           | 1sec |

|           +------+

|  

|  T2       +--------+

|--| |---+--| SUB    |

|        |  | Rgstr- |

|        |  | ip     |

|        |  +--------+

|        |

|        |      M

|        +-----(R)----

The above logic updates the value of loss in weight approximately every 2 seconds. Set the time values according to the update rate needed by you.