Tracking slurry throug dryer zones

I need some inspiration on where to start my Step7 programming, to track slurry as it proceeds trough a dryer with multiple heated zones.


Here is my setup:


[PE]---------|zone1|zone2|zone3|zone4|
_______xxxxx|x____|_____|_____|____x|xxxxxx__->_______conveyor

x=slurry

PE to zone 1 =100cm
PE to end of zone4 =1500cm
I have all the other distances as well
Conveyor is a VFD running at a set cm/sec let say 5cm/sec.

What will be the best way of tracking the slurry as it moves through the dryer zone by zone. (entering and leaving)

I need to track the product with a cm resolution, and I can calculate the time it would take to reach each zone based on the conveyor speed and distance from PhotoEye but
Keep in mind that there might be multiple "blobs" of slurry going through the dryer.
And each zone has to adjust control parameters based if product is present or not.

In my example above I need to adjust Zone1 as the slurry is entering zone1 an also adjust zone 4 as product is leaving that zone4

I have used bit shifts in the past but due the resolution of 1cm it seems impractical?

Any advice will be appreciated.
Thank you
Try55times

This is an interesting problem. What kind of conveyor are using to move the slurry batches through the dryer? Is the slurry conductive? How heavy is the slurry? It's just a thick liquid right?

Depending on the conveyor design perhaps you can sense the presence of the slurry via a load cell arrangement under the pan? Without knowing your process or the design of the dryer, maybe you can sense the change of temperature as a slurry batch enters a zone? If your slurry is conducive and not reactive to electrical current, perhaps you can employ some type of capacitive sensor?

I think I'd stick to the bit register, with 1 bit pr. cm and '1'=slurry present. I'd probably use one fifo per zone, and extend the fifo function to calculate the bitsum of it's contents.

Kalle

use 1500 registers and in each register keep your info, use a pointer which register is on the beginning, like ie number 1000 is so 1000+12 is 12 cm in oven. etc.
you do not need to shift the data only the pointer.
when at end of register just jump to beginning. make register a little longer as the length. no worries. You can use any bit or even byte for info. most plc use a full byte for only one bit.