GE 90*-30 PLC Series User Manual

Also see for 90-30 PLC: Installation and Hardware Manual

Contents

4-16 Series 90™-30 PLC LONWORKS® Bus Interface Module User's Manual – June 1997 GFK-1322A4Initial ValueThis choice allows the user to set the state of the variable upon reset or power-up. Whenusing hold, the last known value is retained through power-down or reset and this valueis used as the initial state. When the initial state is set to zero, the variable is set to zeroon power-up or reset until changed by normal operation. Use the radio button control tochoose the appropriate initial value.BytemapThe bytemap determines the ordering of message bytes when being mapped into registerlocations. For standard network variable types the bytemap is predefined and is notchangeable by the user. When defining custom variables, the bytemap will need to becreated in order to assure that the message is placed in the register space in the desiredmanner. Please see the section of this manual on defining custom variables.Saving a Variable DefinitionUse the pointer to click on the OK command button in the lower right of the screen toaccept the current variable definition. Clicking OK makes a copy of the definition in theproper register configuration while the edit copy remains. To continue adding variablesto the current register, simply change the variable name and any of the other fields thatrequire modification. When finished adding variables to the current register, click on thecancel command button to return to the register configuration screen. Be sure to savethe current variable definition before leaving the screen.Message FieldThe narrow frame in the bottom left of the screen is a message field. In most cases themessage will show information about the number of register locations available at thecurrent entry point. For instance, if a variable is being defined with the starting location0010 and there is a variable defined in location 0015, the space available for the currentvariable would be 5. Errors in the definition will cause error messages to appear in thisarea.