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Control State Model

1. Overview

The Control State Model defines the operational states of the equipment in relation to host control as specified in SEMI E30 (GEM). This model determines who has control over equipment operations.

2. State Diagram

stateDiagram-v2 [*] --> OFFLINE state OFFLINE { [*] --> OFFLINE_EQUIPMENT_OFFLINE OFFLINE_EQUIPMENT_OFFLINE --> OFFLINE_ATTEMPT_ONLINE: Operator Request Online OFFLINE_ATTEMPT_ONLINE --> OFFLINE_EQUIPMENT_OFFLINE: Online Rejected OFFLINE_ATTEMPT_ONLINE --> OFFLINE_HOST_OFFLINE: Online Accepted OFFLINE_HOST_OFFLINE --> OFFLINE_EQUIPMENT_OFFLINE: Operator Request Offline } state ONLINE { [*] --> ONLINE_LOCAL ONLINE_LOCAL --> ONLINE_REMOTE: S1F17 (Host Request) ONLINE_REMOTE --> ONLINE_LOCAL: Operator Request Local } OFFLINE --> ONLINE: S1F17 Accepted (ONLACK=0) ONLINE --> OFFLINE: S1F15 or Operator Request

3. State Definitions

3.1 OFF-LINE States

State Description
EQUIPMENT OFF-LINE Equipment is offline by operator choice. Communication may be enabled.
ATTEMPT ON-LINE Equipment is attempting to transition to online state.
HOST OFF-LINE Equipment is offline due to host request (S1F15).

3.2 ON-LINE States

State Description
ON-LINE LOCAL Equipment is online. Operator has control. Host commands are rejected.
ON-LINE REMOTE Equipment is online. Host has control. Host commands are accepted.

4. Transition Table

# Current State Trigger Next State Action Related Message
1 EQUIPMENT OFF-LINE Operator selects Online ATTEMPT ON-LINE Request online transition -
2 ATTEMPT ON-LINE Transition accepted HOST OFF-LINE Wait for host -
3 ATTEMPT ON-LINE Transition rejected EQUIPMENT OFF-LINE Notify operator -
4 HOST OFF-LINE Operator selects Offline EQUIPMENT OFF-LINE Notify host S6F11
5 HOST OFF-LINE S1F17 received ON-LINE LOCAL/REMOTE Accept request S1F18 (ONLACK=0)
6 HOST OFF-LINE S1F17 rejected HOST OFF-LINE Reject request S1F18 (ONLACK≠0)
7 ON-LINE LOCAL S1F17 received ON-LINE REMOTE Switch to remote S1F18 (ONLACK=0)
8 ON-LINE LOCAL Operator selects Offline EQUIPMENT OFF-LINE Notify host S6F11
9 ON-LINE REMOTE Operator selects Local ON-LINE LOCAL Notify host S6F11
10 ON-LINE REMOTE Operator selects Offline EQUIPMENT OFF-LINE Notify host S6F11
11 ON-LINE (any) S1F15 received HOST OFF-LINE Accept offline request S1F16 (OFLACK=0)

5. Control State Behavior

5.1 ON-LINE LOCAL Mode

In LOCAL mode: - Operator has full control of equipment - Host can read status and variables - Host remote commands (S2F41) are rejected - Host can still configure reports and events

5.2 ON-LINE REMOTE Mode

In REMOTE mode: - Host has control of equipment operations - Host remote commands (S2F41) are accepted - Operator can override to LOCAL if needed - Safety-critical operations may still require operator confirmation

Message Direction Description
S1F15 H→E Request Off-Line
S1F16 E→H Off-Line Acknowledge
S1F17 H→E Request On-Line
S1F18 E→H On-Line Acknowledge

6.1 S1F15 - Request Off-Line

Structure: 

S1F15 W
<L[0]>

6.2 S1F16 - Off-Line Acknowledge

Structure: 

S1F16
<OFLACK>

OFLACK Values:

Value Description
0 Acknowledge, equipment going offline

6.3 S1F17 - Request On-Line

Structure: 

S1F17 W
<L[0]>

6.4 S1F18 - On-Line Acknowledge

Structure: 

S1F18
<ONLACK>

ONLACK Values:

Value Description
0 Accepted
1 Not Accepted, equipment is already online
2 Not Accepted, equipment is not in proper state
SVID Name Type Values Description
[2001] ControlState U1 1-5 Current control state

ControlState Values:

Value State
1 EQUIPMENT OFF-LINE
2 ATTEMPT ON-LINE
3 HOST OFF-LINE
4 ON-LINE LOCAL
5 ON-LINE REMOTE
CEID Name Description
[2001] ControlStateChange Triggered on any control state change
[2002] EquipmentOffline Triggered when entering EQUIPMENT OFF-LINE
[2003] OnlineLocal Triggered when entering ON-LINE LOCAL
[2004] OnlineRemote Triggered when entering ON-LINE REMOTE

9. Operator Interface Requirements

The equipment operator interface must provide:

  1. Status Indicator: Clear display of current control state
  2. Online/Offline Button: Toggle between online and offline states
  3. Local/Remote Switch: Switch between local and remote mode (when online)
  4. Host Command Indicator: Show when host command is being processed

10. Sequence Diagrams

10.1 Host Initiated Online

sequenceDiagram participant Host participant Equipment participant Operator Note over Equipment: State: HOST OFF-LINE Host->>Equipment: S1F17 (Request On-Line) Equipment-->>Host: S1F18 (ONLACK=0) Note over Equipment: State: ON-LINE LOCAL Equipment->>Host: S6F11 (ControlStateChange) Host-->>Equipment: S6F12

10.2 Operator Initiated Offline

sequenceDiagram participant Host participant Equipment participant Operator Note over Equipment: State: ON-LINE REMOTE Operator->>Equipment: Request Offline Equipment->>Host: S6F11 (ControlStateChange) Host-->>Equipment: S6F12 Note over Equipment: State: EQUIPMENT OFF-LINE