NORD Drivesystems BU0200 - Manual (Page 161)

SK 200E Manual for frequency inverters
160 Subject to technical alterations BU 0200 GB-4411
5.4 AS Interface
5.4.1 The bus system
The Actuator -Sensor Interface (AS Interface) is a bus system for the lower field bus level. The transfer
principle is a single-master system with cyclical polling. Up to 31 standard slaves (or 62 A/B slaves in the
extended address range) can be operated on an unshielded two-wire cable up to 100m long and in any
network structure (tree / linear / star). For the AS Interface, since the Complete Specification V2.1 a
differentiation is made between standard and A/B slaves. Version V2.1 includes implements a doubling of
the number of slaves to 62. This is implemented by the double assignment of addresses 1-31 and the
designation "A slave" and "B slave". A/B slaves are labelled via the ID code A and can therefore be uniquely
identified by the master.
SK 225E and SK 235E frequency inverters are standard slaves and correspond to the slave profile S-7.0.
They can be administered by masters whose profile at least corresponds to class M4 (in some cases M3 is
sufficient).
SK 220E and SK 230E frequency inverters are A/B slaves and correspond to the slave profile S-7.A. They
can be administered by masters whose profile at least corresponds to class M4.
In contrast to devices with the profile S-7.0 devices with the profile S-7.A use the extended address range.
Devices with slave profiles S-7.0 and S-7.A can be jointly operated within an ASi network as of version 2.1
(Master profile M4) with observance of the allocation of addresses (see example).
The yellow AS interface cable supplies data and energy. Addressing is implemented via the master, which
can also provide other management functions, or via a separate addressing device. The transfer of the 4 Bit
reference data (in each direction) is performed with effective error protection for standard slaves with a
maximum cycle time of 5ms. Due to the the correspondingly higher number of participants, for A/B slaves
the cycle time (max. 10ms) is doubled for data which is sent from the slave to the master. Extended
addressing procedures for the transmission of data to the slave also cause an additional doubling of the
cycle time to max. 21ms.
The bus system is completely defined in the AS-Interface Complete Specification and is standardised as per
EN 50295, IEC62026.
Permissible
Standard slave 1 (Address 6)
A/B-Slave 1: (Address 7A)
A/B-Slave 2: (Address 7B)
Standard slave 2 (Address 8)
Not permissible
Standard slave 1 (Address 6)
Standard slave 2: (Address 7)
A/B-Slave 1: (Address 7B)
Standard slave 3 (Address 8)