Lenze 931W - Manual (Page 41)

Parameter channel (PCV mechanism)
Access authorisation
7
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41 K-HB 13.0001-EN 2.1
7 Parameter channel (PCV mechanism)
Certain drive functions are further accessed via the parameter characteristic value (PCV)
mechanism.ThePCVmechanismservestoprocess parametersincyclicdataexchange.The
PCV mechanism is used to:
ƒ operate and observe parameters (master -> slave).
ƒ transfer spontaneous messages (slave -> master -> slave).
Moreover, it serves to, e.g.:
ƒ set control authority and parameter change rights
ƒ define setpoints
ƒ
read out status information
ƒ configure limit switches.
Inthe PCV mechanism, the master defines ajob, the slave processes the job and formulates
the response. Jobs and responses cannot be blocked. Each PPO-Write contains exactly one
job and each PPO-Read contains exactly one response. Hence, maximally 4 user data bytes
can be transmitted with one job or one response. In the parameter ID, job/response and
the corresponding parameters are coded.
7.1 Access authorisation
Since the parameter characteristic value mechanism (PCV) serves to access setpoints and
parameters, the user should pay attention to the access authorisation. For setpoint
selection, the PROFIBUS master requires the parameter change rights over the servo
inverter. A simultaneous access of the operating program and a PROFIBUS master is
neither possible nor sensible.
In the ”Level 0” operating mode, the operating program can be used to observe the drive.
When commissioning, the current status of the drive can be observed at the same time. If
the operating program is logged on the servo inverter with an operating mode higher than
”Level 1”, an access conflict occurs and the PROFIBUS master cannot access the drive.
The operating program enables the user to configure the access authorisation of the
PROFIBUS master to the servo inverter, as described in chapter ”Activation of PROFIBUS at
the servo inverter”. ( 18) .