| View previous topic :: View next topic |
| Author |
Message |
IanBart
Joined: 24 Jun 2008 Posts: 3
|
Posted: Tue Jun 24, 2008 10:35 am Post subject: Conveyor cascade control |
|
|
begin conv:sta_cascade_type arriving procedure
if conv:sec_cascade_(aiLine, aiLineIndex+1) current <> 0 then
begin
wait until conv:sec_cascade_(aiLine, aiLineIndex+1) current = 0
wait for vrMtrStart sec
end
inc aiLineIndex by 1
end
Hi!
I use the above code to cascade a load from one conveyor section to the next. Basically, a load cannot leave section A until section B is empty and then only after a further even (i.e. the time to restart a motor).
Does anybody know a better method? Also I the code would be easier to implement if I could return the name of the station to a string on entry to a station arriving procedure. Is this possible?
Cheers,
Bart
PS how do you 'tab' code in this forum? |
|
| Back to top |
|
 |
johngibbons
Joined: 14 Mar 2008 Posts: 21 Location: Holland, MI
|
Posted: Tue Jun 24, 2008 4:47 pm Post subject: |
|
|
Assuming the conveyor system your working in is low rate < 40 cases/minute I would use stations with capacity of 1. If the downstream station is open flow thru otherwise wait on orderlist in current position. After you leave orderlist wait for the prescribed amount of time for things to settle out (motor to start, etc).
If system is hi rate then I would use photoeyes and order lists.
Hope this helps.
John _________________ John Gibbons
LinkedIn Profile http://www.linkedin.com/in/johngibbons1 |
|
| Back to top |
|
 |
IanBart
Joined: 24 Jun 2008 Posts: 3
|
Posted: Wed Jun 25, 2008 1:24 pm Post subject: |
|
|
Thanks John but I think my post lacked information.
The use of photoeyes and order lists is ok when the conveyor system uses a simple section naming convention and is simple (i.e. only one line). But if the system is complex, i.e. multiple lines feeding multiple lines, my initial problem becomes difficult. The previous code in my post is OK for less complex systems where I can define a load attribute at the start of the conveyor run but it gets time consuming and is high maintenance if my system is complex.
I suppose my original question should have been:
I intend to use a table that presents the current section or station in field 1 and the downstream section or station in field 2. So if I am on section sec_124 or at sta_124 and the next section is sec_201 or station is sta_201 I can use my table to reference the status of sec_201 or sta_201. But how do I know I'm on sec_124 or at sta_124? Is there a suitable function I can call from a section arriving procedure or station arriving procedure?
Cheers,
Ian |
|
| Back to top |
|
 |
johngibbons
Joined: 14 Mar 2008 Posts: 21 Location: Holland, MI
|
Posted: Wed Jun 25, 2008 7:23 pm Post subject: |
|
|
Ian,
You may not believe this but I submitted that as an enhancement on March 28, 2008. I asked for ability to let load know what conveyor section its on and to let conveyor procedures and functions be aware of what load is on them too. That page on website is down today but look back on thursday in maintuser section enhancements and you will find it.
Last model I worked on did exactly what you describe - had table that new each section before and after it. I got around issue of knowing what load is on conveyor by writing code for each photoeye in system individually. It was more than a little tedious but it worked. Long section names did not bother me because they were all read in from table.
Model I built had 600 sections and photoeyes and nearly 16000 lines of code to do what you and I asked for. Model runs just fine. 600 photos do put a load on it though.
Hope this helps.
John _________________ John Gibbons
LinkedIn Profile http://www.linkedin.com/in/johngibbons1 |
|
| Back to top |
|
 |
IanBart
Joined: 24 Jun 2008 Posts: 3
|
Posted: Thu Jun 26, 2008 10:30 am Post subject: |
|
|
John,
Thanks for the information. I thought I had missed something obvious. I've decided to write a procedure to read in AutoCad data and then output sections, stations, photoeyes to a conv.asy. I'll then set up a procedure to write out all the station arriving procedures that I need. All this to hold a load back for 1.5 seconds!
I'll add the same request to the enhancements sections.
--
Ian |
|
| Back to top |
|
 |
|