Non Volatile variables Micro 830

With a Micro 830, is it possible to create global variables that can be modified in the logic, or by the HMI, and those modifications will remain non volatile through a power cycle?

thank you

simply yes
please zip and post a copy of your program on this site
what type of HMI the 830 uses modbus for the PV connected component HMI

I can't post anything.

I just want to know if it is possible to create non volatile variables that can be changed both in the ladder logic and in the HMI that will remain unchanged through a power cycle

The user might set a variable at some value that he would not want to have to reset after a power cycle.

thanks

This is a bit of a head-scratcher. My instinct was to say 'of course, all variable are retentive'.

But more careful consideration says that maybe they aren't.

Variables in CCW have an access right attribute: they can be Read/Write, Read Only, or Write Only. Frankly, I'm not sure how these access rights apply to logic or HMI channels. I know I can't write a value to a Read-only variable with ladder logic.

Variables also have an Initial Value, which is applied to them 'when the virtual machine starts the execution of the resource'. That sounds like a fancy way of saying 'when the controller goes into RUN mode'.

The Help file says this can be the default value (usually zero), a value given in the the definition, or a value of the 'Retain' variable when the virtual machine is stopped. Again, that sounds like a fancy way to say powered down.

The Micro 810 controllers have a Retained field in the variable view. Micro 830 controllers don't.

I know for sure that I have timers and such that have the .PT value set via a ladder 1_Gain instruction when user presses a button. Those are Read/Write variables and those survive a power cycle.

So this post is one long "I don't know".

I am working on a project where i need my value to be retain and found the solution after a lot of headache. Not sure if tis works for all but it did in my case.

First build and download your project to a micro830 plc. Then close your project and go to device toolbox -) discover components -) browse connections and select the plc you downloaded your project in. The plc project is loaded in your project and an extra colom in de variables shows "Retain". Activate these values and redownload the project. Now my values are retained. When you do a "save as" you lose this colom again.
Think this is a little bug in the program because i was not able to get te retain colom any other way.

http://www.plctalk.net/qanda/showthread.php?t=81498
I have also been posting here
this is for the HMI mainly

Thanks, it worked just as you said. These big companies have to clean up their act. Companies like Delta will become more and more popular.

Peter, thank you for that post in August. I am resurrecting this thread because I ran into the same problem today with variables not remaining at their last state over a power cycle.

My copy of CCW 1.01 doesn't have that column, even when I browse and upload the controller.

I worked around the issue by using my HMI; I am using a Red Lion G3 Kadet, and it supports retentive variables. I just have it write those variables to the PLC on initialization.

I'm planning on downloading a newer copy of CCW tonight to see if this feature was added after 1.01. My controllers are all still firmware 1.012 so it might not make a difference.

Hi Ken
I recently changed the firmware from an 830 from 1.013 to v4
the program remains in V1.013.
the only way to take advantage of the newer firmware is to copy each section one by one to a new program.
the Global variables tag names or descriptions do not copy over - a real pain in the butt.

I will add that V4 does not need modbus as it will talk via CIP directly.
Modbus is still available