Hello everybody!

I have problem with HSC, i set up everything and encoder is working ok but i can't get hardware interrupt to change state on desired count number

I tried to figure it out via this and other forums but i can't get it to work as  i need it

If i change RV then i get trigger on desired count number but next count is also triggered on same RV and that is not ok i need every count to trigger on new CV

With CV i get that somewhat that i need but then changes low count value, if i must i will adapt to that someway but i would like to get RV function with trigger

So i need interrupt to react on upper count set and with every new count set

thanks

Hello.

UNIOR86

Hello everybody!

I have problem with HSC, i set up everything and encoder is working ok but i can't get hardware interrupt to change state on desired count number

I tried to figure it out via this and other forums but i can't get it to work as  i need it

If i change RV then i get trigger on desired count number but next count is also triggered on same RV and that is not ok i need every count to trigger on new CV

With CV i get that somewhat that i need but then changes low count value, if i must i will adapt to that someway but i would like to get RV function with trigger

So i need interrupt to react on upper count set and with every new count set

thanks

You need two types of interrupts.

1. An event connected to the HSC.
2. An event connected to the edge trigger of the input connected to the encoder.

The trick is to use the ATTACH and DETACH instructions.

1. Create everything in the hardware configuration as you want it. Event1 and Event2 connected to the relevant OBs.
   
   
2. OB100 deactivate (DETACH) the input edge detect event (Event2).
   
   
3. When RV = CV event (Event1) takes place, Event2 is reactivated (ATTACH).
   
   
4. If you have an encoder that goes up and down in counting, then it becomes tricky. You will have to find a way to evaluate in which direction is the count changing in. Event2 is then toggled between activation and deactivation.

Is this what you were looking for?

BR

Ok, tnx for your reply i will try that

I didn't encounter those blocks for HSC until you said it

Hello.

UNIOR86

Ok, tnx for your reply i will try that

I didn't encounter those blocks for HSC until you said it

Do you mean ATTACH and DETACH?

Configuring interrupt events in the Hardware Configuration of the PLC will make the assumption that you will restart the PLC with the interrupts activated. In most cases that is true. In most cases there is no need for the ATTACH and DETACH instructions.

What you want to do is however a bit against the grain (for Siemens PLCs). There is no way that I know of (now) to clear the trigger to force it to retrigger. Then remains to activate the event on your say-so.

An alternate way is to not worry about activation of the edge-trigger-interrupt-event. Have it activated by default. In the OB handling the command will be some option coding to verify if it has permission to execute. If no permission -> Exit the event OB.

I'm doing bending machine...so after i input angle on HMI, machine must go to that angle via motor and stop there (turn off motor)

After that machine goes again at zero angle and waits for another angle input for bending

So when i turn on machine i need to externaly reset counter to 0 with microswitch in zero position and then input bending angle via HMI, angle must be always visible also either way if counting forward or backward because operator needs to know current angle position

tnx for replying fast!

Hello.

UNIOR86

I'm doing bending machine...so after i input angle on HMI, machine must go to that angle via motor and stop there (turn off motor)

After that machine goes again at zero angle and waits for another angle input for bending

So when i turn on machine i need to externaly reset counter to 0 with microswitch in zero position and then input bending angle via HMI, angle must be always visible also either way if counting forward or backward because operator needs to know current angle position

tnx for replying fast!

Was there a follow-up question hidden in your reply? Without joking this time - thank you for the feedback. Sounds like an interesting project. You may even find some notes about such machines if you used the search facility.

Are you open for an alternative idea?

Consider capturing the HSC value. See the HSC configuration. There is some PLC addresses mentioned there. One of which is something like %ID1000 (input double word size) which can be liked to a tag of DINT type. Assume "myEnc" as a name.

Now you use "myEnc" in your code. To calculate a relative distance, you can capture "myEnc" at that moment, let say "reference".

"relative_distance" := "myEnc" - "reference";

This will allow more accurate measurements. More control also on controlling slow-to-stop position to ensure accurate standstill position. Overshoot / undershoot can also be detected and compensated for.

Reaction from physical entities (example: hydraulic valve) takes time. There is a dead-time delay. Triggering these inside interrupts means nothing. Predictive positioning is required instead to ensure accurate standstill position.

Note that "myEnc" is a buffered value. It is updated at each start of PLC scan. When processing "myEnc" inside an interrupt you may need the real-time value. This is achieved by using "myEnc":P .

Unhappily I am not available to spoon-feed you on the proper way (IMO) of doing things. So consider the above notes carefully and decide how you are going to approach your project with your own research.

Good luck.