PROFIBUS-DP CONNECTION
The ProfiBus-DP Network Digital Resolver model is enclosed in
either a size 25--2.5" (63.5 mm) dia. or size 40--4.0"
(101.6 mm) dia., NEMA 13 housing. It is available as a flange
mount (size 25), a servo mount (size 25), or face mount (size 40)
model with a ProfiBus-DP connector at the end.
Variety
of Outputs
The Network Digital Resolver is available with Binary, Gray Code,
or BCD absolute position output formats.
Power
Supply
An existing power supply can be used to power the Network Digital
Resolver. That is, if a PLC operates at 24 VDC, a 1632 VDC
Network Digital Resolver model can be connected to the same power
supply, thus cutting the system cost.
Flexible
Programming of Counts-Per-Turn
The advanced R-to-D converter used in the Network Digital
Resolver has made it possible to program any number of scaled
Binary, BCD, or Gray Code counts-per-revolution. The default
encoding format is set to 10-bit Gray Code.
PROFIBUS-DP (PROCESS FIELDBUS)
The ProfiBus-DP Network Digital Resolver was designed to operate
within a ProfiBus-DP Communication System. Serial fieldbuses are
used today primarily as the communication system for exchange of
information between automation systems and distributed field
devices. Thousands of successful applications have provided
impressive proof that use of fieldbus technology can save up to
40% in costs for cabling, commissioning, and maintenance, as
opposed to conventional technology.
ProfiBus-DP
specifies the technical and functional characteristics of a serial
fieldbus system in which decentralized digital controllers can be
networked together from the field level to the cell level.
ProfiBus-DP distinguishes between master devices and slave
devices.
Master
devices determine the data communication on the bus. A
master can send messages without an external request when it holds
the bus access rights (the token).
Slave
devices are peripheral devices. Typical slave devices include
input/output devices, valves, drives and measuring transmitters.
They do not have bus access rights and they can only acknowledge
received messages or send messages to the master when requested to
do so.
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PROFIBUS-DP
SLAVE NETWORK DIGITAL RESOLVER
ProfiBus-DP
is designed for high-speed data transfers at the sensor actuator
level. At this level, controllers (e.g., PLCs, PCs, etc.) exchange
data with their field devices (I/0, drives, valves, resolvers,
etc.) via a high-speed RS-485A serial link. Most of the data
communication with these distributed devices is done in a cyclic
manner.
RS-485A
transmission is the transmission technology used by ProfiBus, and
it is very easy to handle. Installation of the twisted-pair cable
does not require expert knowledge. The bus structure permits
addition and removal of stations or step-bystep commissioning of
the system without influencing the other stations.
Transmission
speeds between 9.6 kbps and 12 Mbps can be selected. One unique
transmission speed is selected for all devices on the bus when the
system is commissioned.
The
unit is designed to be a single-turn DP Slave Network Digital
Resolver on a ProfiBus-DP network. The unit is configured to look
like one 16-bit output word and one 16-bit input word to the
network. Four bits of the output word select the encoding format
and scale factor of the resolver. The other 12-bits of the output
word are unused. 10- or 12-bits of the input word are used for the
encoded position data. The unused bits of the input word are
always zero.
If
no output word from the ProfiBus-DP Master is written to the
output word after power-up ... the output word is set to zero. The
default zero encoding format is selected.
The
Network Digital Resolver's position data can be encoded in three
different data formats. For each data format there is a choice for
maximum counts-per-revolution. The following are the possible data
encoding format choices:
As
a slave on the ProfiBus‑DP network, the Network Digital
Resolver does not initiate any communications. It responds to
requests from the DP Master. Data exchange commands must be
initiated from DP masters. Output encoding data is sent from a DP
Master as a 2 byte output word (16-bits). Byte N is the most
significant 8 bits of the data word. Byte N + 1 is the least
significant 8 bits of the data word. Input position data is
returned to a DP master device from the DP Network Digital
Resolver slave as a 2-byte input word (16 bits). Byte N is the
most significant 8-bits of the data word. Byte N+ is the least
significant 8-bits of the data word.
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