System and Memory Integer

[Tejasvini]

Greetings!!

I am new to visilogic and I have noticed two types of integer (system and memory) used in the plc programming software.  Can anyone clarify the differences between these two types.

Looking forward to hear from you.

Tejasvini Yadav

 

[DanT]

Hi Tejasvini;

 

The differences between   SI and MI

SI  - System integers  -- used by the PLC Operating system  to provide feedback on system process

          Also Date and time are here.

         Gives status of  Communications ( Modbus and Ethernet and so much more )

        Basically most are read only for programmer to monitor and use in the ladder ( Date and Time can be edited)

Anything starting with   S    SI, SB, SL,SDW   are system   variables.

 

MI  -- These are for you, the programmer to use in your progam as needed. 

Aslo   MB, ML, DW           --  These are backed up by the Battery, so on power loss, data is retained   ( There is an SB  for Battery Status )

XB,XI,XL  etc  are scratch pad variables for the programmer to use - you don't care if these get wiped on power fail.

 

DanT

 

 

   

[Cara Bereck Levy]

What Dan said 🙂
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