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photo eye and merge controller interaction

I am trying to stop a conveyor with a photo eye and merge at the same time with the merge controller.

Every time that the condition is met to stop the conveyor the merge controller does not pass the torch to the conveyor that can move and it goes into limbo.

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photo eyemerge controller
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joshua fischer avatar image joshua fischer commented ·

These is what i have so far. i made the photo eye set label mc_nextReleaseLane in the merge controller and it will work up to simulation time 129.85 but it gets hung up and the simulation time stops.

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Sam Stubbs answered joshua fischer commented

I'm not sure what you're using the photo eye for. If the photo eye is supposed to be a controlling mechanism for the merging, the merge controller should already be able to handle what you want. The reason the model is getting stuck, is because n your Lane Clear Table in the Merge controller properties, it's missing a "check" in one of the key cells.

You need to make sure Straight Conveyor 19 is able to be opened after the slug from Conveyor 1 passes. You shouldn't need to stop/start the motor via photo eyes, the Merge Controller already handles what can pass through. I reattached your model with thechanges. (I just set the photo eye off to the side, since it wasn't needed here.)

1808-conveyorsystem-autosave.fsm


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joshua fischer avatar image joshua fischer commented ·

these is the scope that i'm working with.

4. Then, the photo-eye PE01-BL will look for a gap between the boxes. When a long enough gap is detected, the blade stop on conveyor 01 will be moved to the UP position and, after a delay, the blade stop on conveyor A2001 will be moved to the DOWN position, allowing boxes accumulated on conveyor A2001 to move forward, resuming the original normal conditions. 5. When the blade stop on conveyor A2001 is UP and the blade stop on conveyor 01 is DOWN, having the boxes coming on conveyor 01 passing through the merge, if there is a high enough number of boxes on conveyor 01 traveling back-to-back, eventually the boxes on conveyor A2001 will accumulate up to the position of the photo-eye PE2001-FL. When that situation happens, the interlock to the motor of conveyor 01 will be disabled, causing the motor to stop. After a delay, the blade stop on conveyor A2001 will be moved to the DOWN position, allowing the boxes accumulated to be released. Then, the photo-eye PE2001-BL will look for a gap between the boxes. When a long enough gap is detected, the blade stop on conveyor A2001 will be moved to the UP position and, after a delay, the interlock to the motor of conveyor 01 will be enabled, allowing the motor to start running, resuming the previous conditions (same as per step 4).

6. When the photo-eye PE02-FL detects accumulation or a “jam” (detected by having the photo-eye blocked for more than a pre-determined time), the motor on conveyor A2001 will be stopped and the interlocks to the motors of conveyors 01 and 02 will be disabled, causing those motors to stop. At the same time, a Beacon Light will be turned ON, indicating that a jam has occurred. An operator will then need to clear the jam and press a “Reset” pushbutton, which will turn OFF the Beacon Light and will also turn ON the motor of conveyor A2001 and enabling the interlocks to motors of conveyors 01 and 02, returning to the previous conditions.

so the photo eye was to stop conveyor1 and then let the other boxes on straightconveyor19 go through until the photo eye saw a gap then it will resume it previous condition.

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joshua fischer avatar image joshua fischer commented ·

This is the whole scope:

1. To start production (start running the conveyors A2001, A2002 and A2003 and enabling the interlock to run conveyors 01 and 02) there will be a “Start” / “Stop” pushbutton. When pushing the “Start” button, a warning horn will sound for a few seconds before the conveyors start running. The conveyor A2001 has a drive with motor, which will drive also conveyors A2002 and A2003, mechanically slaved from conveyor A2001.

2. In normal conditions, the blade stop on conveyor A2001 will be down, allowing boxes coming on conveyor A2001 to pass through the merge conveyor A2003. The blade stop on conveyor 01 will be up, stopping the boxes coming on conveyor 01.

3. When the boxes on conveyor 01 accumulate up to the location of the photo-eye PE01-FL (detected by having the photo-eye blocked for more than a pre-determined time), the photo-eye PE2001-BL will look for a gap between the boxes. When a long enough gap is detected, the blade stop on conveyor A2001 will be moved to the UP position and, after a delay, the blade stop on conveyor 01 will be moved to the DOWN position, allowing boxes accumulated on conveyor 01 to move forward.

4. Then, the photo-eye PE01-BL will look for a gap between the boxes. When a long enough gap is detected, the blade stop on conveyor 01 will be moved to the UP position and, after a delay, the blade stop on conveyor A2001 will be moved to the DOWN position, allowing boxes accumulated on conveyor A2001 to move forward, resuming the original normal conditions.

5. When the blade stop on conveyor A2001 is UP and the blade stop on conveyor 01 is DOWN, having the boxes coming on conveyor 01 passing through the merge, if there is a high enough number of boxes on conveyor 01 traveling back-to-back, eventually the boxes on conveyor A2001 will accumulate up to the position of the photo-eye PE2001-FL. When that situation happens, the interlock to the motor of conveyor 01 will be disabled, causing the motor to stop. After a delay, the blade stop on conveyor A2001 will be moved to the DOWN position, allowing the boxes accumulated to be released. Then, the photo-eye PE2001-BL will look for a gap between the boxes. When a long enough gap is detected, the blade stop on conveyor A2001 will be moved to the UP position and, after a delay, the interlock to the motor of conveyor 01 will be enabled, allowing the motor to start running, resuming the previous conditions (same as per step 4).

6. When the photo-eye PE02-FL detects accumulation or a “jam” (detected by having the photo-eye blocked for more than a pre-determined time), the motor on conveyor A2001 will be stopped and the interlocks to the motors of conveyors 01 and 02 will be disabled, causing those motors to stop. At the same time, a Beacon Light will be turned ON, indicating that a jam has occurred. An operator will then need to clear the jam and press a “Reset” pushbutton, which will turn OFF the Beacon Light and will also turn ON the motor of conveyor A2001 and enabling the interlocks to motors of conveyors 01 and 02, returning to the previous conditions.

7. When steps 5 or 6 occur, there must be a minimum time delay (10 sec.) from the time the motors are stopped to the time the motors are started again. This time delay is necessary to prevent the motors to be cycled too frequently.

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Sam Stubbs avatar image Sam Stubbs ♦ joshua fischer commented ·

I think I've created an example something that fits your specifications better. I'm sorry I misunderstood you earlier. Instead of using a merge controller, which uses "slugs" as its measurement of what is allowed or not allowed. I created a system of checks with the photo eyes and decision points as your requirements specify (in steps 2-4 especially).

To begin with I created a decision point on each lane that will act as the "gate" or "blade" that prevents items from passing. In these decision points I created a numeric label called "gateclosed" that is either a 1 or a 0, being closed or open respectively. (By the specifications the top lane is closed at the beginning and the bottom is open, so I just set those values and checked the "Automatically Reset Labels" box.) Then in the OnArrival trigger on the Decision Point gates I have it check if the "gateclosed" label is 1 or 0, if it's 1 then the item entering is stopped, and it assigns that item to label on the DP for later reference.

Second I created a PhotoEye that is placed where you want the top lane to be "backed up to." In that Photo Eye's properties I set the block time to 5 to ensure that blocks are triggered only when the items are actually backed up. Then I set some functions on the On Block trigger. It sends two messages: One to each of the DP gates, one that sends a message parameter of 1 and the other a 0 (the "open and close" states of the "gates")

Back in the Decision Point gates' properties I added the following code in the OnMessage trigger.

if (msgparam(1)==1) {
setlabel(current,"gateclosed",1);
}
if (msgparam(1)==0) {
setlabel(current,"gateclosed",0);
conveyorresumeitem(getlabel(current,"stoppeditem"));
}

This says that if the message is a 1, close the gate, if the message is a 0 open the gate and resume the stopped item.

Finally I created a photo eye right behind the top lane DP gate. In it's properties I set its "Clear Time" to 5. (This is an arbitrary number you can decide the time you wish to set, but this is indicative of the "looking for an opening" idea included in the details of your outline.) Here that "opening" is set to 5 time units between items. When that Photo Eye clears, it is saying that there are no more items backed up or flowing through lane 1, and then it sends the two messages (like the above Photo Eye) telling the gates to close and open, reverting back to the normal conditions outlined at the first.

I'm including the example of the model I created below. You may decide to do as I suggested earlier and try to have the Merge Controller system mimic the behavior of the photo eyes instead if you find that simpler. But between this and the ideas included in the Merge Controller section of the manual you should be equipped with the tools you need to fit these examples to your outline's specifications. Good luck

fischerconveyorexample.fsm

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joshua fischer avatar image joshua fischer Sam Stubbs ♦ commented ·

thank you so much these is what i needed.

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