BECKHOFF AX2000 PROFIBUS DP communication profile - Manual (Page 36)

5.1.1 Control word (STW)
With the aid of the control word, you can switch from one amplifier state to another. In the diagram
for the state machine you can see which instrument states can be reached by which transitions. The
momentary amplifier state can be taken from the status word.
Several states may be passed through during one telegram cycle, e.g.
Ready for switch on ® Ready for operation ® Operation enabled.
The bits in the control word can be (operating-) mode-dependent or mode-independent.
The following table describes the bit assignment in the control word.
Bit Name Commentary
0 Switch on —
1 Inhibit voltage —
2 Fast stop, switch-on inhibited
1 -> 0 drive decelerates using emergency ramp, axis is disabled
(See also ASCII-commands STOPMODE and DECDIS)
3 Operation enabled —
4 Fast stop (inhibit rfg)
1 -> 0 drive decelerates using emergency ramp,
the amplifier remains enabled
5 Pause (stop rfg) Operating mode dependent, 1 -> 0 stops motion
6 Setpoint enable Operating mode dependent (see table below)
7 Reset Fault only effective with errors
8 Jogging (on/off) Operating mode dependent (see table below)
9 reserved —
10 PZD (enable/inhibit) —
11 Start homing run (edge) Operating mode dependent (see table below)
12 Manufacturer-specific reset the position
13 Manufacturer-specific acknowledge warnings
14 Manufacturer-specific
only position opmode: Bit14 = 1: PZD section is interpreted as direct
motion block (velocity 32-bit, position 32-bit, motion block type 16-bit
Bit14 = 0: PZD section (HSW) is interpreted as motion block number
15 Manufacturer-specific Operating mode dependent, digital speed
Depending on the bit combination in the control word, a corresponding control command is defined.
The following table shows the bit combinations and also determines the priorities of the individual
bits, in case several bits are altered in one telegram cycle.
Command Bit 13 Bit 7 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Transitions
Shutdown X X X X 1 1 0 2, 6, 8
Switch-on X X X X 1 1 1 3
Inhibit voltage X X X X X 0 X 7, 9, 10, 12
Fast stop (amplifier is disabled) X X X X 0 1 X 7, 10,11->12
Fast stop (amplifier remains enabled) X X 0 1 1 1 1 11
Inhibit operation X X X 0 1 1 1 5
Enable operation X X 1 1 1 1 1 4, 16
Reset error X 1 X X X X X 15
Acknowledge warnings 1 X X X X X X -
Bits labeled with X are irrelevant.
Opmode-dependent bits in the control word:
Mode Bit 5 Bit 6 Bit 8 Bit 11
Position
Motion block:
The parameter that is set in the mo-
tion block is used.
Setup operation:
The parameter that is set as a ramp
for homing and jogging is used
Start a motion task with every
transition edge
(toggle bit).
Start
jogging
Start homing
Digital speed
Drive brakes, using the preset
speed ramp.
Setpoint enable, start movement reserved reserved
Digital current reserved Setpoint enable, start movement reserved reserved
Analog speed reserved reserved reserved reserved
Analog current reserved reserved reserved reserved
Trajectory reserved reserved reserved reserved
Priority of the Bits 6, 8, 11 in position-control mode: 6 (high), 11, 8 (low).
36 PROFIBUS for AX2000/2500
Process data channel
12/05
BECKHOFF