Sign in to follow this  
Followers 0
junkyardgary

Emerson (GE) memory map data types

3 posts in this topic

 I've always had this Allen-Bradley memory map taped on my wall in my office. It used to be handy to use, until I remembered al of the prefix letters for each data type. Now I am using Emerson (GE) the old proficy software now called PAC ME machine edition. Now I'm finding it's about impossible to find the data type list amongst the thousands of help files, videos, ect... it seems like a simple thing to find, but I'm not having any luck. They use I and Q for regular inputs & Outputs, but there are R files, M files, S files, N files, G files, ect.... this is old-school PLC software that doesn't use tag names. 

 Is there a steadfast rule for each type, or can they be used for any type of data? Dazed and confused...  

memory map.PNG

Share this post


Link to post
Share on other sites

Discrete data types:
%I - Real world inputs

%Q - Real world outputs

%M - Discrete internals. You can use %M memory for numeric data as long as the starting address of the variable is on a byte boundary. 

%S, %SA, %SB, %SC - Status bits

%G - Somewhat of a throwback to the old days of Logicmaster (DOS) software. Discrete internals. I tended to use %G memory for HMI bits.

%T - Another throwback, but still discrete internals. You can assign the same %T address to as many coil -( )- instructions as you want.

Numeric data types:

%AI - Real world analog inputs

%AQ - Real world analog outputs

%R - 16-bit internals.

You can use tag names instead of addresses in the Rx3i. In the 90-30 all variables will have an address, but you can assign a tag name to a variable and use it instead of the address. 

The problems most people have when migrating from one brand to another arise from trying to make the new brand behave like the brand you're accustomed to. Of course it doesn't help when the new brand doesn't use the same terminology as the old. It's hard to find what you're looking for in the help files when you don't know the right keywords.

Share this post


Link to post
Share on other sites

Exactly what I was looking for. I'm seeing coils that are M's, some G's but see no real difference in their use. My background included Modicon and Mitsubishi, which are similar to the Emerson, but some of the data types use different prefixes. I was aware of the tag name in the newer PLC's (thank God), so I was able to troubleshoot my first machine. Now I'm doing some service work on older Emerson stuff, and stumbling around in the dark trying to figure out why and how it works.

Your last paragraph sums it up quite nicely. 

Thanks for your time, sir. 

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0