Using Statusword and Controlword

Overview

What are Control- and Statusword?

Commands are sent by the master to the drive with the controlword and the drive sends information about its state back to the master with the statusword.

The controller is run through a state machine as defined in the CiA402 standard. The state changes are requested by the master using the controlword object 0x6040 and the slave will show the actual state in the statusword object 0x6041.

Only bits 0,1,2,3 and 7 in the controlword are used to change the state of the controller.

Only the first 7 bits of the statusword reflect the controller state.

How are they used?

The controlword and statusword should be used as defined in the CiA402 standard.

Manufacturer and Operation mode specific bits

Some bits of controlword and statusword are dependent on the operation mode the drive is in, some bits of the statusword are also set by the manufacturer. Please check the section of each mode for details about which bits have which meaning.

Bits in Status- and Controlword

The finite-state automaton (FSA) shows different states of the drive and how the transitions between them can be executed.

../../../_images/state_machine.png

Statusword

General structure

  • The basic bits (0-7) are identical in each mode.

  • The red marked bits 9 and 14-15 are not supported (N/A)

  • The yellow marked bits have a specific functions which depends on the mode the drive is currently in. See the documentation of the specific mode for details.

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ms oms oms ila tr rm ms w sod qs ve f oe so rtso
N/A operation mode specific bits N/A basic

The basic bits of the statusword indicate in which state the drive is:

State coding

Statusword

FSA state

xxxx xxxx x0xx 0000b

Not ready to switch on

xxxx xxxx x1xx 0000b

Switch on disabled

xxxx xxxx x01x 0001b

Ready to switch on

xxxx xxxx x01x 0011b

Switched on

xxxx xxxx x01x 0111b

Operation enabled

xxxx xxxx x00x 0111b

Quick stop active

xxxx xxxx x0xx 1111b

Fault reaction active

xxxx xxxx x0xx 1000b

Fault

Note

  • If bit 4 of the statusword is 1 that means that voltage is applied to the drive.

  • If bit 5 of the statusword is 0 that means that the drive is in quick stop active state.

  • If bit 7 of the statusword is 1 this indicates the presence of a warning condition.

  • If bit 11 is 1 this indicates that one of the control values has been limited. See table 1.

  • Bits 9, 14 and 15 are not used.

Legend

Abbr.

Meaning

rtso

ready to switch on

so

switched on

oe

operation enabled

f

fault

ve

voltage enabled

qs

quick stop

sod

switch on disabled

w

warning

ms

manufacturer-specific

rm

remote

tr

target reached

ila

internal limit active

oms

operation mode specific

ms

manufacturer specific

Mode specific bits

Mode of operation 13 12 11 10 8
Profile Position Following error Set-point acknowledge Internal limit Active Target reached N/A
Profile Velocity N/A Speed bit
Profile Torque N/A
Cyclic Synchronous Position Target position ignored
Cyclic Synchronous Velocity Target velocity ignored
Cyclic Synchronous Torque Target Torque ignored
Homing N/A

Internal limit Active bit

The values that are limited by this bit differ in each mode:

Limiting object

Limited value

Operating modes

Max torque (0x6072)

Torque demand value (0x6074)

All

Max torque (0x6072)

  • Target torque (0x6071)

  • Torque offset (0x60B2)

PT / CST

Max. motor speed (0x6080)

Velocity demand value (0x606B)

CSP / PP

Max. motor speed (0x6080)

Profile velocity (0x6081)

PP

Max. motor speed (0x6080)

Target velocity (0x60FF)Velocity offset (0x60B1).

CSV / PV

Software position limit (0x607D)

Position demand value (0x6062)

CSP/PP

Legend:

PP: Profile Position

PV: Profile Velocity

PT: Profile Torque

CSP: Cyclic Synchronous Position

CSV: Cyclic Synchronous Velocity

CST: Cyclic Synchronous Torque

Controlword

General structure

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ms ms ms ms ms r oms h fr oms oms oms eo qs ev so
N/A basic operation mode specific bits basic

Note

bits 9,10,11,12,13,14 and 15 are not used.

Legend:

Abbr.

Meaning

so

switched on

ev

enable voltage

qs

quick stop

eo

enable operation

oms

operation mode specific

fr

fault reset

h

halt

oms

operation mode specific

r

reserved

ms

manufacturer specific

State Coding

Command b7 b3 b2 b1 b0 Transitions
Shutdown 0 x 1 1 0 2,6,8
Switch on 0 0 1 1 1 3
Switch on + enable operation 0 1 1 1 1 3+4 (NOTE)
Disable voltage 0 x x 0 x 7,9,10,12
quick stop 0 x 0 1 x 7,10,11
disable operation 0 0 1 1 1 5
enable operation 0 1 1 1 1 4,16
Fault reset 1 x x x x 15
NOTE Automatic transition to Enable Operation state after executing SWITCHED ON state functionality.

Mode specific bits

Mode of operation 8 7 6 5 4
Profile Position Halt N/A N/A Change set immediately New set-point
Profile Velocity Halt N/A
Profile Torque Halt N/A
Cyclic Synchronous Position No Operation mode specific bits used
Cyclic Synchronous Velocity
Cyclic Synchronous Torque
Homing Halt N/A Homing operation start

Timing Diagram

../../../_images/Brake,-command,-status.png