NORD USS and Modbus RTU Manual
30 Subject to technical amendments BU 0050 GB-3111
1.5.3.3 Control word (STW)
The control word (STW) is the first word transferred to the frequency inverter in the process data area in an
order telegram. For example, a control word "Ready for switch-on" corresponds to 047E
(hex)
.
Reverse with the brake ramp, with disconnection from supply at f=0Hz
Cut off voltage; the inverter output voltage is switched off; the FI enters a state
where switching on is disabled.
Quick stop with programmed quick stop time; with disconnection from supply at
f=0Hz; the FI switches to starting disabled condition.
Cut off voltage; the inverter output voltage is switched off; the FI enters a state
where switching on is enabled.
The output voltage is enabled; ramp to the existing setpoint
Ramp generator is set to zero; no disconnection from supply at f=0Hz; FI remains
in the operation enabled state.
The setpoint currently provided by the ramp generator is "frozen" (frequency is
maintained).
Enable setpoint on ramp generator
Selected setpoint value is set to zero on the ramp generator.
Selected ramp generator setpoint is activated.
With the switch from 0 to 1, errors which are no longer active are acknowledged.
Note: When a digital input has been programmed for the "ack.fault" function, this
bit must not permanently be set to 1 via the bus (otherwise, edge evaluation
would be prevented).
Bus bit 8 from the control word is set. (Only for SK 200E and SK 500E)
For further details of the function please refer to parameter (P480).
Bus bit 9 from the control word is set. (Only for SK 200E and SK 500E)
For further details of the function please refer to parameter (P480).
The transmitted process data is invalid.
Valid process data is transferred from the master.
Note:If setpoints only are transferred via the bus, this bit must be set so that the
transferred setpoint is valid.
Rotational direction:
right
Rotational direction right (priority) ON*
Rotational direction:
left
Rotational direction left ON*
Bit 0 to switch
parameter set
00 = Parameter set 1
01 = Parameter set 2
10 = Parameter set 3
11 = Parameter set 4
Bit 1 to switch
parameter set
* If Bit 12=0, then "Direction of rotation right ON" applies