FB/DB Issue

Hi again DP,

I have attached a PDF file of the entire project, hopefully it's readable.

Ok, so during simulation, the 'virtual motors' 1, 2 and 3 are running but only motor 1's running times actually increase. I am monitoring the time values in DB4 (In the PDF motor 1 shows 19 seconds and 5 mins while motor 2 and 3 show 0 running seconds, yet all 3 blocks are true)?

DB4 is a data block I created to store all time values that can be accessed easily for HMI displays.

Do you know the reason for this?

Many thanks, David 

DS_7

Hi again DP,

I have attached a PDF file of the entire project, hopefully it's readable.

Ok, so during simulation, the 'virtual motors' 1, 2 and 3 are running but only motor 1's running times actually increase. I am monitoring the time values in DB4 (In the PDF motor 1 shows 19 seconds and 5 mins while motor 2 and 3 show 0 running seconds, yet all 3 blocks are true)?

DB4 is a data block I created to store all time values that can be accessed easily for HMI displays.

Do you know the reason for this?

Many thanks, David 

 FB1, Network 1: M500.0 & M100.5

Please do not use global accessed variables in your FB. Create a STATIC variable that belongs to the DB that will be linked to the FB when called.

For the 1 second pulse (M100.5), it would be best to have that enter through an input like #Motor_Running  is doing.

Cheers.

Hi DP

I removed the global memory bits M100.5 and M500.0 from inside the function block FB1. I then created an input within the block where I connect the M100.5 with a positive edge when I call the FB1 in my FC1.

I see the reason why the other two virtual motors are not counting but I cannot see the mistake in my programming maybe?

When I monitor the FB1 online while simulating, the M0.1 bit activates the #Motor_Running input to trigger the counter. BUT for M0.2 and M0.3 bits the #Motor_Running DOES NOT activate to trigger the counter.

But if I monitor the same input in the data block DB2 and DB3 it does recognize the #Motor_Running input is TRUE?

I'm very confused lol

Thanks David

Hello DS_7,

Perhaps this might help:

How do you monitor a block with the desired call environment in STEP 7?

Best regards,

Wizard

DS_7

Hi DP

I removed the global memory bits M100.5 and M500.0 from inside the function block FB1. I then created an input within the block where I connect the M100.5 with a positive edge when I call the FB1 in my FC1.

I see the reason why the other two virtual motors are not counting but I cannot see the mistake in my programming maybe?

When I monitor the FB1 online while simulating, the M0.1 bit activates the #Motor_Running input to trigger the counter. BUT for M0.2 and M0.3 bits the #Motor_Running DOES NOT activate to trigger the counter.

But if I monitor the same input in the data block DB2 and DB3 it does recognize the #Motor_Running input is TRUE?

I'm very confused lol

Thanks David

David,

Sorry to say - I am not following your thoughts exactly. I am not even sure what you changed. Just to make my own suggestions clear:

The variable declaration of FB1 is going to start playing a role. See if you can figure out how to have Step7 print out your program as a PDF - please.

Regards.

Ok, I have created and attached a PDF for this entire S7 project. Some of the text on the side is cut off but it should be readable.

Are you sure what my question is about this code? If you are unsure please ask and I will explain in more detail.

thanks guys, David

 David,

DS_7

Ok, I have created and attached a PDF for this entire S7 project. Some of the text on the side is cut off but it should be readable.

Are you sure what my question is about this code? If you are unsure please ask and I will explain in more detail.

thanks guys, David

My previous post had helpful hints in a picture. Sadly the picture is not shown with the text. I have trouble now extracting that picture, but modified the previous posting by adding a screen capture of how the post was suppose to look.

Please go back and see how the message was meant to look.

--

You have an enemy in using "dummy" (M500.0). The POS instruction should have a unique boolean on the M-BIT input.

Exchange as follows:

FC1, Network 5:   M500.0    <-->   M500.1

Test it. Now you will see that FB1, DB2 and DB4.DBW8 now changes as expected.

--

It was not my intention to ask you to change the instructions you use. The concept you had was okay.. but the use of "dummy" in FB1 was a problem. If you go to your original design and change "dummy" to a STAT bit  (a new "neighbour" to  #Trigger_Counter), you will already see things work.

Am I making more sense to you now?

DP,

Yeah, I made your recommended modifications and the program worked perfectly. 

I created a dummy 1 (M500.0), dummy 2 (M500.1) and dummy 3 (M500.2) memory bits for the POS instruction in each FB1 call. Now all motor's running hours are recorded within DB4.

Thank you so much for your patience DP and all other users that helped me!  

Thanks David.

DS_7

DP,

Yeah, I made your recommended modifications and the program worked perfectly. 

I created a dummy 1 (M500.0), dummy 2 (M500.1) and dummy 3 (M500.2) memory bits for the POS instruction in each FB1 call. Now all motor's running hours are recorded within DB4.

Thank you so much for your patience DP and all other users that helped me!  

Thanks David.

Thank you for the news, David.

Please do know that what you have is not an optimized solution, but it should work. You will have to ask questions if you want to make this solution "better". Though the "better" is academical and you will not see a difference in functioning.

Watch out for those M500.x bits. These bits should not be used anywhere else in your program. That means MB500, MW500 and MD500 is also illegal for usage anywhere else in your program. The POS instruction is very possessive and do not share with others.

Hi DP,

Thanks for your reply.

I am interested in hearing your advice on improving my design, how would you make this solution better?

Yeah, I see the problem with using the m500.X dummy bits as they may cause overflow or data error if used else where in any code. Would you still use the POS instruction for this project or what way would you do it?

Thanks, David