higher resolution encoder now with BSL

[ghriver]

Hi everyone, we have a working part rejector already. The issue is the new encoder went from 100ppr to 1024ppr.
Hardware is compactlogix 1769-l16er-bb1b.
Now i cant see many pulses at all so i was going to install the 1734-vhsc24 highspeed counter module.
Before i make the purchase i was programming/reading about the modes. Is one of the modes capable of returning 1 pulse per 10? Would counter with preset be the correct mode to use to achieve this to trigger the bit shift left?

Thanks.

 

[Jim3846]

Question: What speed is the conveyor?
Speed is a factor in determining encoder selection and the length of product your trying to reject.

I gave an idea that might get you to think on by a spreadsheet calculation. This should give you an idea on what would work. The green area is the processor can capture the pulses at the speed. The red area is the processor will miss pulses and cant do this. You can create the same spreadsheet to calculate the same thing based on 3 parameters.

High speed counter will work if you want to go that route.
Have you looked into Timed interrupt task or maybe an event task where the encoder pulse drives the event task?
Time interrupt task needs to sample the input 2x of one cycle of the encoder pulse.

I am sure there is more to this but this is a start.

 

[GaryS]

The incoming pulse rate is now over 10 X the rate the pulse width is not long enough for the plc to count it
you will need to install the high speed counter and reconfigure the system

 

[kamenges]

I don't think the 1734-VHSC has any type of count division mode that you could directly use. However, you can probably make one.

Set the rollover count to 10. Then set one of the outputs to turn on at 3 counts and off at 8 counts. At that point you can either wire the encoder card output directly to the input that the original encoder went to OR you can change the plc program to use the status of the output in the plc logic.

Keith

 

[ghriver]

thats exactly what i was looking for. I will wire the windowed output to the input so i dont have to deal with RPI to the 1734-vhsc module. Thanks so much.

I don't think the 1734-VHSC has any type of count division mode that you could directly use. However, you can probably make one.

Set the rollover count to 10. Then set one of the outputs to turn on at 3 counts and off at 8 counts. At that point you can either wire the encoder card output directly to the input that the original encoder went to OR you can change the plc program to use the status of the output in the plc logic.

Keith