CIP Sync: State Machine

The device control of the AKD2G can be used to carry out all the motion functions in the corresponding modes, which are Homing Mode and Cyclic Position Mode. The control of the AKD2G is implemented through a mode-dependent state machine. The mode of operation is set through the Manufacturer Specific Bits 11 and 12 (see Mode-dependent bits in the Controlword). There are separate state machines for each axis.

The fieldbus state machine controls the axis as long as AXIS#.CMDSOURCE is equal to “Fieldbus”. To enable the axis using WorkBench and bypass the state machine, a command source other than “fieldbus” should be selected for AXIS#.CMDSOURCE. During commissioning and performing initial procedures like tuning, it is recommended the fieldbus master is OFF (not running) or not connected and the command source is “Service”.

State Machine

State Machine Description

State	Description
Not Ready for Switch On	Axis is not ready to switch on, initialization has not completed.
Switch On Disable	Axis is ready to switch on, parameters can be transferred, the bus voltage can be switched on, motion functions cannot be carried out yet.
Ready to Switch On	Bus voltage may be switched on, parameters can be transferred, motion functions cannot be carried out yet.
Switched On	Bus voltage must be switched on, parameters can be transferred, motion functions cannot be carried out yet.
Operation Enable	No fault present, output stage and motion functions are enabled.
Quick Stop Active	Drive has been stopped with the emergency ramp, output stage is enabled, motion functions are not enabled.
Fault Reaction Active	A fault has occurred, the drive is in process of stopping with the quick stop ramp.
Fault	A fault is active, the drive has been stopped and disabled.

Transitions of the state machine

The state transitions are affected by internal events (ex: switching off the bus voltage, WorkBench enable/disable) and by the flags in the controlword (bits 0,1,2,3,7).

Transition	Event	Action
0	Reset	Initialization
1	Initialization completed successfully. The axis is ready to operate.	None
2	Bit 1 Disable Voltage and Bit 2 Quick Stop are set in the controlword (Shutdown command). Bus voltage may be present.	None
3	Bit 0 is also set (Switch On) and bus voltage is present	None
4	Bit 3 is also set (Enable Operation)	Torque is applied to axis and motion function is enabled, depending on the mode that is set.
5	Bit 3 is canceled (Disable Operation)	Output stage is disabled. No torque applied to motor.
6	Bit 0 is canceled (Shutdown)	None
7	Bits 1 and 2 are canceled (Quick Stop / Disable Voltage)	None
8	Bit 0 is canceled (Shutdown)	Output stage is disabled. No torque applied to motor.
9	Bit 1 is canceled (Disable Voltage)	Output stage is disabled. No torque applied to motor.
10	Bits 1 and 2 are canceled (Quick Stop / Disable Voltage)	Output stage is disabled. No torque applied to motor.
11	Bit 2 is canceled (Quick Stop)	Drive is stopped with the emergency braking ramp. The output stage remains enabled. Setpoints are canceled (motion block number, digital setpoint, speed for jogging or homing). Bit 2 must be set again to perform any further motion.
12	Bit 1 is canceled (Disable Voltage)	Output stage is disabled. No torque applied to motor.
13	Fault reaction active	Execute appropriate fault reaction
14	Fault reaction is completed	Drive function is disabled. The power section may be switched off.
15	"Fault Reset" command received from host	A reset of the fault condition is carried out if no fault exists currently on the drive. After leaving the state Fault the Bit 7 'Reset Fault' of the controlword must be cleared by the host.
16	Bit 2 is set	Motion function is re-enabled as long as the quick stop action has completed and standstill has been reached.

Controlword

The control commands are built from the logical combination of the bits in the controlword and external signals (example: enable output stage).

Bit assignment in controlword

Bit	Name
0	Switch on
1	Disable voltage
2	Quick stop
3	Enable operation
4	Operation mode specific
5	Reserved
6	Reserved
7	Reset fault (only effective for faults)
8	Pause/Halt
9	Reserved
10	Reserved
11	Select Home Mode
12	Select Cyclic Position Mode
13	Reserved
14	Reserved
15	Reserved

Controlword bits 11-15 mode

Controlword bits 11-12 are defined to be manufacturer specific; bits 13-15 are reserved. For AKD2G, specific modes can be set for each bit that defines the behavior.

Commands in the controlword

Command	Bit 7 Fault Reset	Bit 3 Enable Operation	Bit 2 Quick Stop	Bit 1 Disable Voltage	Bit 0 Switch On	Transitions
Shutdown	X	X	1	1	0	2, 6, 8
Switch on	X	X	1	1	1	3
Disable voltage	X	X	X	0	X	7, 9, 10, 12
Quick stop	X	X	0	1	X	7, 10, 11
Disable operation	X	0	1	1	1	5
Enable operation	X	1	1	1	1	4
Fault reset	1	X	X	X	X	15

Bits marked by an X are irrelevant.

Mode-dependent bits in the controlword

The following table shows the mode-dependent bits in the controlword. Only manufacturer-specific modes are supported at present. The individual modes are set by object Manufacturer Specific Bit 11 (Homing Mode) or Bit 12 (CIP Sync Cyclic Sync Position Mode).

Operation Mode	Bit 4	Bit 5	Bit 6	Bit 9
Homing Mode (hm)	Start Homing Operation	Reserved	Reserved	Reserved
CIP Sync Cyclic Sync Position Mode (csp)	Start Cyclic Position following	Reserved	Reserved	Reserved

Description of the remaining bits in the controlword

The remaining bits in the controlword that are not used for drive state machine commands or operation mode specific commands are used for special operations:

Bit 8 – Pause/Halt: If bit 8 is set, then the drive halts (pauses) in all modes. The set-points (speed for homing or jogging, motion task number, setpoints for digital mode) for the individual modes are retained.

Statusword

The momentary state of the state machine can be read with the aid of the statusword.

Bit assignment in the statusword

Bit	Name	Description
0	Ready to switch on	Controlled by state machine
1	Switched on	Controlled by state machine
2	Operation enabled	Controlled by state machine
3	Fault	Axis fault is active
4	Voltage enabled	Bus voltage is present
5	Quick stop	Controlled by state machine
6	Switch on disabled	Controlled by state machine
7	Warning	Axis warning active
8	STO – Safe Torque Off	STO is preventing drive from enabling (AXIS#.SAFE.STO.ACTIVE)
9	Remote	1 – Fieldbus in control (AXIS#.CMDSOURCE = Fieldbus) 0 – WorkBench in control (AXIS#.CMDSOURCE = Service)
10	Target reached	Axis has reached target value. In Profile Position Mode and Homing Mode the position window is set using AXIS#.SETTLE.P. The bit is also set on coming to standstill on Halt bit (bit 8 of Controlword = 1) or after Quickstop (bit 2 of Controlword = 0) with quick stop option code 5 or 6.
11	Internal limit active	This bit is controlled by the conditions below: Set if motion is being commanded into a limit switch and clears when moving out of a limit switch. Set if a controlled stop is in progress (SS1, action table, etc.) and clears once the controlled stop is complete. The drive is usually disabled at the end of most controlled stop actions and this bit will clear. Set while Wake and Shake is active.
12	Operation mode specific (reserved)	Home Attained
13	Operation mode specific (reserved)	Home/Position Following Error
14	Ramp Down Requested	Motion Mode Selected (0 = Homing, 1 = Cyclic Position)
15	Manufacturer-specific (reserved)	Following Position

States of the state machine

Bits marked by X are irrelevant.

State	Bit 6 Switch on Disabled	Bit 5 Quick Stop	Bit 3 Fault	Bit 2 Operation Enabled	Bit 1 Switched On	Bit 0 Ready to Switch On
Not ready to switch on	0	X	0	0	0	0
Switch on disabled	1	X	0	0	0	0
Ready to switch on	0	1	0	0	0	1
Switched on	0	1	0	0	1	1
Operation enabled	0	1	0	1	1	1
Fault	0	X	1	0	0	0
Fault reaction active	0	X	1	1	1	1
Quick stop active	0	0	0	1	1	1

Mode-dependent bits in the statusword

The following table shows the mode-dependent bits in the statusword.

Modes of Operation	Bit 12	Bit 13
Homing mode (hm)	Homing attained	Homing error
CIP Sync Cyclic Position Mode (csp)	Reserved	Following error