Manual

Operating Characteristics 3-1
3. Operating Characteristics
This section describes the working characteristics of the GES-1993. It is divided
into sections, and each of these sections describes a particular aspect of the GES-
1993's operating characteristics.
3.1 Communications States
The GES-1993 represents the current state of its SECS link using a Communication
Finite State Machine diagram. The purpose is to make clear how this link is initiated
and terminated.
GWGEM SW maintains the GEM Communications State finite state machine
([RefGWGEMUser] p. 65 ’Establish Communication’). However, the
Communications State machine informs FmNT through the user written
NoteLinkState() function of any changes in the Communications State.
FmNT is responsible for the following:
 Setting data in the GCD file ([RefGWGEMRef] (See page 3 – Communication’).
 Configuration GCD data and the GemEnable function. ([RefGWGEMUser] (See
page 71 ‘Power Up’, p. 72 ‘Configuration’).
 Providing a Process Link State Change extension routine ([RefGWGEMRef]
NoteLinkState).
 GUI display of the current State( GEM Status control ).
 Handling transaction failures ([RefGWGEMUser] (See page 71 ‘Failing
Transactions’).
The Communications State is displayed in the GEM status bar and the SECS/GEM
page of Run Window.
Initially, the INITCOMMSTATE variable is set to place the Equipment into the
Disabled state at power up. Once FmNT has completed initialization, FmNT will
change the Communications State to the default communication state selected by the
user. The loss of communications during Running or Pausing will not affect the
ability of FmNT to complete operations in the Process Program. However, automatic
reestablishment of the Process State may require manual intervention if FmNT has
changed state during the loss of communications period.