adccommunitymod (AutomationDirect) asked a question.
Created Date: October 17,2019
Created By: ridefst
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As far as I can tell, I'm looking for a relay that doesn't exist - so maybe I'm going about this the wrong way. I 've got a conveyor feeding a variety of small parts in waves, so there's 19 ' of product, then a 3 ' gap, etc etc The product is feeding into a drying oven with multiple trays, so it cycles trays during the 3 ' gap, but needs triggered to start loading a tray. This originally was done by a photoeye right in front of the loading conveyor, so when it saw a product, it would start loading immediately for a preset amount of time. I'm trying to replace that photoeye with a light curtain for better small part sensing, but due to space I have to locate the bar a little earlier on the conveyor (15.2 seconds earlier, to be exact) So, I need to sense the product, but then delay the output of the light bar for 15.2 seconds every time. Sensing of the products within the wave of product doesn't much matter, the initial trigger is the only important one. Additionally, the timing needs to be paused if the conveyor is paused. I started off with a CTT-AN-D24 multi-function timer, as it has a pause feature. However, in Signal On Delay 1 mode a reset signal is needed to stop the output. I tried wiring the output to the reset but that gave me a very short output pulse, too short for the drying oven to reliably detect. I then added another timer relay MS4SM-CE-ADC to the reset of the first, but it also needs a reset signal, so again I wired the output to the reset of this timer, resulting in a very brief signal to reset the first timer - this appears to also be too short for the timer to reliably detect as it's failing to reset several times a day (it works most of the time though) I can't find a timer relay anywhere that seems to do exactly what I want (delay on make, retriggerable) so I'm trying to figure out a different way. Maybe this is better done with a PLC, but that seems overkill for this little function. It would be pretty neat simply delay all the sensor data by 15.2 seconds exactly, not sure if a putting data into a string would do what I need? Seems this should exist somewhere already, maybe I don't know the right words to search for... Any ideas? Thanks!
Created Date: October 17,2019
Created by: kewakl
Overkill. Maybe.
$77 for a dedicated timer/counter/tach that may or may not have the features you need.
$82 for a basic serial CLICK PLC with relay out and AC or DC inputs that you can program the features that you need today -- or tomorrow.
Overkill is however you define it.
Created Date: October 17,2019
Created by: quaizywabbit
+1 to Kewaki's thinking.
Created Date: October 17,2019
Created by: Garry
+1 Kewakl
A simple click PLC with a shift register.
https://accautomation.ca/plc-programming-example-sorting-station-shift-register/
Here is a shift register using the click.
https://accautomation.ca/click-plc-shift-register-instruction/
Regards,
Garry
Created Date: October 17,2019
Created by: ridefst
Alright, I'm not gonna argue against three people telling me to get going with a PLC!
I 've done a bit of programming on a Click for some other projects, but I'm no expert.
If I'd add an encoder of some sort to the conveyor (incremental, quadrature), could I use that to step the register, so this can accommodate varying conveyor speeds? It's only really got two speeds, varied not more than once per day, so I was just going to change the timing as needed, but this could be even better.
Created Date: October 17,2019
Created by: ridefst
Additional question, Click or BRX?
I 've used both, BRX more recently.
Created Date: October 17,2019
Created by: Garry
Yes, your encoder or proximity switch on a sprocket would control the shift (clock) input of the shift register. This controls the timing, so no adjustment of your program when speeds change.
Regards,
Garry
Created Date: October 17,2019
Created by: Garry
Both are good controllers. Click was mentioned because of your simple application.
Created Date: October 17,2019
Created by: kewakl
Both are good controllers. Click was mentioned because of your simple application.
Yes! Exactly.
Created Date: October 17,2019
Created by: quaizywabbit
Additional question, Click or BRX?
I 've used both, BRX more recently.
your budget$$ and your preference. if you plan on any future expansion, buy once, cry once.
Created Date: October 17,2019
Created by: deep6ixed
As a rule I 've used at my shop, more that a timer or a counter, use a click.
Any chance of analog or where I might even need advanced features, use a BRX