BECKHOFF AX2000 PROFIBUS DP communication profile - Manual (Page 12)

2.2.2 Important amplifier configuration parameter
The following parameters configure the amplifier for the Profibus interface. They can be set using
the setup software for the amplifier.
EXTWD (PNU 1658)
With this parameter, the observation time (watch dog) for the fieldbus-slot communication can be
set. The observation is only active, if a value higher than 0 is assigned to EXTWD (EXTWD=0,
observation switched off) and the output stage is enabled. If the set time runs out, without the
watchdog-timer being newly triggered by the arrival of a telegram, then the warning n04 (response
monitoring) is generated and the drive is stopped. The amplifier remains ready for operation and the
output stage enabled. Before a new driving command (setpoint) is accepted, this warning must be
deleted (function CLRFAULT or INxMODE=14).
ADDR (PNU 918)
With this command, the node address of the amplifier is set. When the address has been changed,
all parameters should be saved to the EEPROM and the amplifier switched off and on again.
Since the modular structure of the AX2500 as a multi-axis system requires its own addressing,
there is the additional parameter ADDRFB (PNU 2012) for this series, with which a field bus
address different from the internal device address (ADDR) can be defined. As long as ADDRFB =
0, ADDR is the bus address. If ADDRFB > 0, then ADDRFB is the bus address. ADDR is set auto-
matically by the AX2500 master module in descending order.
AENA (PNU 1606)
With this parameter, the state of the software-enable after switch-on can be defined. The soft-
ware-enable allows an external control to enable/disable the output stage. For amplifiers with ana-
log setpoints (OPMODE=1,3) the software-enable is set automatically after switch-on and the devi-
ces are ready for operation immediately (if hardware-enable is present). For all others,
software-enable will be set to the value of AENA. The variable AENA also has functionality when
resetting the amplifier after an error (by digital input 1 or the CLRFAULT command). If an error can
be reset by the software, the software-enable is set to the value of AENA after the error is cleared.
In this way the behavior of the amplifier after a software-reset is similar to after the drive is switched
on.
INPT, INPT0 (PNU 1904)
With INPT a delay for the in-position message can be set. With the start of a motion task the
in-position message is deleted and the monitoring of the position is activated after expiration of the
adjusted time. This function is particularly important for positioning procedures within the in-position
window. In this case the in-position message is delayed for a defined time.
12 PROFIBUS for AX2000/2500
Installation / Setup
12/05
BECKHOFF