Siemens SIMATIC Box PC 820, Manual

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4-3
Box PC 820 / PC FI45 V2, Manual
A5E00051531-03
4.2 Functional Description
The direct key module is employed to scan keys via the PROFIBUS DP within a
defined time-slot pattern. The module as such is configured as a PROFIBUS norm
slave on PROFIBUS DP. PROFIBUS reaction time guarantees a scanning of the
keyboard within the time limit defined for PROFIBUS.
The direct key module always serves as a slave on the PROFIBUS DP. Triggering
or scanning the direct key module is always executed by a DP master, which
operates the direct key modules via layer two of the seven-layer module. After
having received a trouble-free PROFIBUS message, the direct key module
independently generates the requested response messages (acc. to DIN standard
E19245 T3). Default setting of the slave provides the structuring of the digital
inputs and outputs as well as the data transfer modes. Data transfer to and from
the direct key module is always consistent and determined by a default setting.
With this module it is possible to scan for 32 direct keys (assigned to the digital
inputs DI 0.0-0.7, DI 1.0-1.7, DI 4.0-4.7 and DI 5.0-5.7) as well as to scan for or
control 16 digital outputs (DO 0.0-0.7 and DO 1.0-1.7) with 24V/100mA and 16
digital inputs (DI 2.0-2.7 and DI 3.0-3.7) with 24V levels via PROFIBUS DP.
The direct key module supports transmission rates of 9.6 Kbps to 12 Mbps.
To set the PROFIBUS address (node address) of the direct module via PROFIBUS
use either the ET200 hand held device or a programming device/PC (with an
MPI-/DP port) with STEP 7 software installed (see Hardware Config) or
COMPROFIBUS software.
Once the PROFIBUS address (node address) is set, it is stored in the direct key
module. Even after disconnecting your Industrial PC from the power supply, the
settings remain saved.
Note
On delivery, the PROFIBUS address (node address) is set to 126. A direct key
module supplied with the default address 126 in accordance with DP regulations,
can be assigned a different address by the user after installation. It is essential
that this address setting is carried out because otherwise no data can be
exchanged with the direct key module (DP nodes with the address 126 do not by
definition participate in data exchange).
Direct Key Module (Optional with FI45)
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