Problem with OP77A

bassambassam

Member
B
Join Date
Jan 2012
Location
Cairo
Posts
6
Hi all

I'd a SCADA system with HMI OP77A, and it's required to make a State and Forced variables (I mean to write an address of my plc and get it's value and to write an address and to force a value to this address)

I have a 41 address in my project on SIMATIC300.

ANY HELP ??
 
What is the adres syou use inside the plc?

Do you write information to this adress by means of the plc-program?

How do you use this adres within the plc-program?
 
You cannot "force" inputs or outputs by means of an OP77A.
Values of internal addresses such as Merkers and DBs can be modified, but not "forced" to stay at a certain value.

If you just need to change internal values, you use regular input/output fields in the OP77A program.
If need to achieve some kind of "forcing", it has to be combined with some code in the PLC. The code must read the "force" values and block other code from changing the merker/DB values.
 
ivo.maenen said:
What is the adres syou use inside the plc?

Do you write information to this adress by means of the plc-program?

How do you use this adres within the plc-program?
Click to expand...

All what i want to make is to make a field on op77a to make the client write the address he would like to read and another field to obtain the result (value of this address)

and vice verse:
to write the address and to force a value for this address
 
JesperMP said:
You cannot "force" inputs or outputs by means of an OP77A.
Values of internal addresses such as Merkers and DBs can be modified, but not "forced" to stay at a certain value.

If you just need to change internal values, you use regular input/output fields in the OP77A program.
If need to achieve some kind of "forcing", it has to be combined with some code in the PLC. The code must read the "force" values and block other code from changing the merker/DB values.
Click to expand...

yeah, I just need to read and modify my DBs on PLC...
is it possible with JUST one IO Field tool output and one IO Field Input????
 
NOTE: but i want to know many addresses, It means that I want the Input IO Field to understand the address that i write and the output IO Field to Display the Value of that address
 
bassambassam said:
NOTE: but i want to know many addresses, It means that I want the Input IO Field to understand the address that i write and the output IO Field to Display the Value of that address
Click to expand...
I'd like to believe that "Multiplexing" is a solution for what you are after.
Only problem is that it needs to be setup (logic needs to be added in order to display the right outout field depending on the selected input field).

Another issue is that for "single" points this will work but if ou are planning on accessing Analogue I/O in addition to digital then this won't work.

Another option may be "Scripting" but I avoid it at all costs as it complicates things a bit when a maintenance person scans through the code and cannot find any reference that can be "looked at".
Maybe someone who does use scripts can help out.
 
bkottaras said:
I'd like to believe that "Multiplexing" is a solution for what you are after.
Only problem is that it needs to be setup (logic needs to be added in order to display the right outout field depending on the selected input field).

Another issue is that for "single" points this will work but if ou are planning on accessing Analogue I/O in addition to digital then this won't work.

Another option may be "Scripting" but I avoid it at all costs as it complicates things a bit when a maintenance person scans through the code and cannot find any reference that can be "looked at".
Maybe someone who does use scripts can help out.
Click to expand...

Am thankful for ur reply, and I'd like to add that I thought about Multiplexing ,, but i didn't know how to implement it at all :( :( ,, i configured at as Prog's help, but i don't know steps to make the client insert the address that he wants to modify and where the address should be displayed ,, i can't see any respond on Runtime window!!
 

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