CRA - Auto. CRH - Manual. Who says?

There is a convention for PLC documentation. I read it but forgot where. I can't even give a decent example of what I mean about conventions for documentation other than CRA is automatic and CRH is manual. Does this ring a bell for anyone?

Thanks for your help;
Frank

I worked on an old machine with relay logic controls and the relays were labelled that way in the (hand drawn) schematics. I thought the CRH was a typo, so I changed it to CRM when I made changes to the drawings and recreated them in AutoCad. I would guess that CRH might stand for "Control Relay Hand". Hand mode being equivalent to Manual Mode.