Movement Delay Integrator

[Bjørn Aspheim 0]

I'm working on a project where we inspect the temperature of a produced pipe in a mill at several different locations with pyrometers. Each measurement are inspected for over or under temperature and we shall activate a spraygun localized after the last pyrometer to mark the any section of pipe out of spec. This seems like a very easy task, but we have to take into account that the line speed can vary during the period from the fault is detected to the time when the pipe is at the spraygun. Also the fact that we may get several faults before they actually reach the spraygun complicates things. We have so far used totalizers, but you need lots of them to be able to track several faults. Anyone knows if there are available a delay module where you can have a line speed input controlling the delay? Other suggestions?

[TimWilborne 108]

How hot is the pipe? Could you put some type of measuring device such as an encoder on it and use this to tell when the pipe has traveled the distance from the sensor to the spray gun? How do you measure the line speed?

[Ron_Smith 13]

Ditch the Totalizers and go with a PLC?

[Beuwolf_1 0]

I kind of like the PLC idea, temperatures can be monitored along with the line speed and movement. Then maybe something as simple as a bit shift would be able to turn on the sprayer. Don't know if this is practical for your application, but it has worked for me pretty well in the past.

[Bjørn Aspheim 0]

Thanks for response. The pipe temperature is 800 to 1100 degrees celsius (red hot that is for you Farenheit users...) Putting on encoders would be to complicated. We receive the line speed from the mill PLC via a Profibus interface as an analog value. When I wrote Totalizers it is not one of those counters yoy can buy, it is a buildt in block in our main controller from Eurotherm. It integrates the linespeed and gives an output when it has reached its target, the target beeing the distance from measurement to spray gun. Anyway, this causes us to have a lot of these, bacause they can only handle one fault each. I have been thinking of a bit shift as Beuwolf 1 wrote. Do anyone have an example where this is done? I have also been looking for a hardware module where you apply a Boolean signal to the input and the output is delayed with a time based on a varying analog value.

[Beuwolf_1 0]

I think that the Allen Bradley has one of the easiest bit shifts to program and understand. But without doing the actual programming its just a way of assigning a one or zero to say when to spray. I hope i'm not going to insult anyone's intellegence by my really poor example of a bit shift but what the heck 00000000000000000001111111111100000000000000000 The 0's are the cool spots and the 1's are the area to be cooled. A calibrated pulse, say every inch, would index the 1's to the "right", the least significant bit would be the point of spray. 00000000000000000000000011111111111000000000000 (five pulses later) 00000000000000000000000000000000111111111110000 (eight pulses later) 00000000000000000000000000000000000001111111111 (start spraying) 00000000000000000000000000000000000000000001111 (spraying till all the 1's land in the bit bucket) I really hope this isn't overly simple or anyone thinks I'm tryin to insult their intelegence, but it was the easiest way I could think of to explain a bit shift right in real people terms.

[Mickey 71]

Bit Shift explained http://www.mrplc.com/kb/index.php?page=index_v2&id=71&c=12