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Consider the General Notes on the Information in the Pepperl+Fuchs Product Catalogs
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Copyright Pepperl+Fuchs
16.08.12
AS-Interface
Simply insert the flat cable into the module and, depending on
the housing design, close the module or attach the top part. Most
modules can be mounted without tools or by using just one screw. The
connection to AS‑Interface is established using the penetrating, gold-
plated, twisted contact pins.
A black flat cable is used for a 24 V power supply to provide high power
to outputs.
Installation
The AS‑Interface cable is symmetrical, i.e., you must not connect
either of the strands to the system ground. You can place a branch at
any point (any topology layout) where the cable end does not require
a terminator. If you use a bus termination at the far "cable end," the
segment length is extended to 200 m. Using a maximum of two further
repeaters in a row and three bus terminations in each segment, you can
achieve a maximum distance of 600 m from the master. You can also
use repeaters in a star-shaped topology to achieve a possible 1 km total
network length.
Power from the AS‑Interface power supply is supplied at any point within
the AS‑Interface segment. In the event of high current slaves, position
the power supply close to the slaves in order to keep the voltage drop
low. A 24 V additional power supply may be required when connecting
powerful actuators, in order to operate them via the electronic outputs.
The 24 V power supply can be connected several times locally.
AS‑Interface masters/gateways are supplied with 24 V directly or from
the AS‑Interface.
Commissioning of the AS‑Interface segment can take place directly at
the master/gateway without a PC.
Pepperl+Fuchs offers an extensive range of connectors for connecting
sensors and actuators.
7.4
AS‑Interface Technical Characteris-
tics
Number of slaves on the AS‑Interface segment
and functionalities
AS‑Interface is backward compatible, meaning that even the very
first generation of slaves will still function with the current master. You
can connect up to 62 slaves to one AS-Interface segment. These can
have up to four inputs and four outputs enabling 248 input signals and
248
output signals to be connected per network. These addresses
are counted sequentially from 1A to 31A and 1B to 31B for historical
reasons. As safe slaves require both an A and a B address, you can
connect a maximum of 31 safe nodes to one segment. Slaves are also
referred to as A/B slaves if they only require either an A or B address
and standard slaves if they require a full address.
Several outputs can be switched simultaneously within 1 µs via the
"
synchronous mode" parameter bit.
Diagnostic function with peripheral errors
In addition to communication errors (such as faulty telegrams), the
master also detects hardware errors at the slave. These peripheral error
messages can be transferred to the control unit and used to perform
shutdowns in the event of an error.
A peripheral error is indicated by a red LED on the module itself. Some
slaves also offer the option to display the inputs/outputs affected.
Analog value transfer
Analog values are transferred in several cycles and are then sent as a
complete analog value, typically 16-bit, from the master to the control
unit. Seven cycles are required for each channel for the transfer time
and approximately 10 ms conversion time.
Transfer rate and cycle time
The maximum cycle time is
10
ms. If the segment is not fully
occupied, the cycle time reduces
by 0.15 ms per slave. If a module
has four inputs and four outputs,
the maximum cycle time for the
outputs only is a maximum of
20
ms. If the corresponding B
address is released, the cycle time
for the respective slave with the A
address is halved. Standard slaves
with a full address always have a
maximum 5 ms cycle time.
This enables both time-critical
applications and applications with
multiple inputs and outputs to be set up on the same segment.
9.9
Programming and Installation
Plant size
By specifying the sensors and actuators you wish to connect, you can
determine the required number of modules and addresses. Note that
analog modules and safety modules occupy a full address (A and B).
Estimate the required length for the segment. Incorporate a bus
termination for lengths over 100 m. Incorporate repeaters with
downstream AS-Interface power supply for distances over 200 m.
As AS‑Interface is not restricted by topology, you can route the cables
freely.
Power supply dimensioning
You can determine the required power supply from the power
consumption of the individual devices. The relevant data is included in
the data sheets.Then, select the AS-Interface power supply and specify,
if necessary, the required 24 V
DC
power supply through the output load.
Assigning an address to the slaves and wiring
Prior to mounting, you have the option of assigning an address to all
the slaves, labeling them, and installing them at the planned mounting
location, or you can use the VBP-HH1-V3.0-KIT handheld device to
assign addresses once installation is complete. It is common to assign
addresses locally following installation.The default address for all slaves
on delivery is 0. The slaves are connected and assigned an address via
a programming plug, the M12 plug on the device, or the socket on the
addressing device.
2
T
P
VBA-2E-G11-I/U/PT100
AUX
AS-i
FAULT
1
T
P
I
1
I
2
U
2
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1
INT
EXT
Overload
AS-Interface
7
