The first step in a Grafcet-chain.

 At least one InitStep object has to be included in
 every sequential chain.

 The object is active when the PLC program that contains
 the object is to start running.
 The PlcPgm object has an attribute, ResetObject, where
 the name of a Di , Do, or Dv object is specified. This
 attribute is used as a reset signal in one or more
 sequential chains in the PLC program in the following
 way. When the reset signal makes the transition:

  - 0 -> 1 each Step, InitStep and Order object in the
    PLC program becomes inactive. Stored orders are
    aborted.
  - 1 -> 0 the InitStep object(s) of the PLC program
    becomes active.

 If individual reset signals are required for every
 single sequential chain the number of sequential chains
 has to be limited to one per PLC program.
 The vertical connections are connected to Trans
 objects.

 The horizontal connection may at the same time be
 connected to one or more Order objects as well as one
 or more Stoxx , Setxx or Resxx objects; see figure 3-51
 on page 3-328. It may also be left open or used as an
 ordinary binary signal; see figure 3-22 on page 3-184.

 Figure below shows how an InitStep , ISO, may be configured
 in a straight sequential chain. A chain is said to be straight
 if it does not contain any branching.

 InitStep Object in a Straight Sequential Chain

 The And object in figure below will be executed every time when
 the PLC program executes. The compilation may result in a warning
 'No Grafcet standard' because of the connections between the And
 object and the Order respectively InitStep object, but the solution
 works

 Example of the Use of Step- and Order Status as an Ordinary Binary Signal

 Used by the PLC Editor.

 Used by the PLC Editor.

 Specifies the state of the step. FALSE means an
 inactive step and TRUE means an active step. The value
 may be picked up in another program by means of a GetDp
 object.
 Order[0] is an output both to Order and Trans objects.

 It is set by the preceding Trans object. The subsequent
 Trans object checks both Order[0] and Order[1]. If
 Order[0] = Order[1] = TRUE Order[0] is cleared by the
 subsequent step.
 In the structure of the object or referenced this
 attribute is named Status[0].

 Order[1] is a dummy variable that follows Order[0].
 In the structure of the object or referenced this
 attribute is named Status[1].