Nord Drivesystems NORDAC LINK SK 155E-FDS - Page 69

4 Commissioning
BU 0155 en-3520 69
Bus I/O bits
WARNING
Unexpected movement due to automatic starting
In the event of a fault (communication interrupted or bus cable
disconnection) the device
automatically switches off, since the device enable is no longer present.
Restoration of communication may result in an automatic start and therefore unexpected movement
of the drive unit. To prevent any hazard, a possible automatic start must be prevented as follows:
• If a communication error occurs, the bus master must actively set the control bits to “zero”.
The device is equipped with two additional digital inputs for connecting initiators. However, there are
no optional outputs for connecting actuators which are operated directly via the BUS. The following
connections are each provided for four reference data bits:
BUS-IN Function (P420[-05…-08])
Status
Status
Bit 1 Bit 0
Bit 0
Enable right
0
0
Motor is switched off
Bit 1
Enable left
0
1
Field of rotation right present at
motor
Bit 2
Acknowledge fault
1)
1
0
Field of rotation left present at motor
Bit 3
Release brake manually
2)
1
1
Motor is switched off
1)
Acknowledge with flank 0

1.
For control via the bus, acknowledgement is not
automatically performed by a flank on one of the enable
inputs
2)
0 = Brake applied, will be released automatically if
required
1 = Brake is released immediately.
BUS-OUT Function (P434 [-04 … -05])
Status
Status
Bit 1 Bit 0
Bit 0
Fault (status bit 0)
0
0
Error active
Bit 1 Operation (status bit 1) 0 1 Standby (motor stationary)
Bit 2
1)
Initiator 1 status (BDI1)
1
0
Warning (but motor running)
Bit 3
1)
Initiator 2 status (BDI2)
1
1
Run (motor running without warning)
1)
Bits 2 and 3 are directly coupled to digital inputs BDI1
and BDI2.
Parallel actuation via the BUS and the digital inputs (BDI1, BDI2) is possible. The relevant inputs are
dealt with more or less as normal digital inputs. If a changeover between manual and automatic is
going to take place, it must be ensured that no enable via the normal digital inputs takes place in
automatic mode. This could be implemented e.g. with a three-position key switch. Position 1: "Manual
left" Position 2: "Automatic" Position 3: "Manual right".
If an enable is present via one of the two "normal" digital inputs, the control bits from the bus system
are ignored. An exception is the control bit "Acknowledge fault". This function is always possible in
parallel, regardless of the control hierarchy. The bus master can therefore only take over control if no
actuation via a digital input takes place. If "Enable left" and "Enable right" are set simultaneously, the
enable is removed and the motor stops without a deceleration ramp (block voltage).