User's Manual

Table Of Contents
A5E32337685 SITRANS LR260 (PROFIBUS PA) – OPERATING INSTRUCTIONS Page 121
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G: Communications PA
Defining the device as Profile-specific as opposed to Manufacturer-specific makes it
possible to exchange the device for any other device of the same profile type without
changing the GSD file.
To set up SITRANS LR260 as a profile device see PROFIBUS Ident Number (PROFIBUS
IDENT) (4.4.) on page 85.
Configuring a device
See
Configuring a new device
on page 38.
Configuring PROFIBUS PA with an S7-300/ 400 PLC
1. If SITRANS LR260 is not listed in the STEP 7 device catalog, you can download the
DeviceInstall file from the Siemens Milltronics Web site and run it from your
computer. Go to https://pia.khe.siemens.com/index.asp?Nr=7427
and click on
Downloads.
2. Add the SITRANS LR260 “rack”: click on and drag the SITRANS LR260 folder from
the hardware catalog.
3. Fill the rack with desired modules, by dragging and dropping them from the
hardware catalog.
4. After configuring PROFIBUS PA in steps 2 and 3, download it to the PLC.
5. Add code to the PLC program to read data consistently using the SFC14.
Cyclic versus Acyclic Data
When you request data from a device via PROFIBUS PA, you have two choices. Cyclic
data is provided at every bus scan: acyclic data is requested and provided as needed.
Input information is always requested at every bus scan and is set up as cyclic data.
Configuration information is only needed periodically and is set up as acyclic data.
Cyclic Data
When you configure SITRANS LR260 on the PROFIBUS PA bus, there are two slots
available for modules.
Slot 0 always transmits AIFB1 information
1)
; slot 1 defaults to Free Place, but can be
changed to AIFB2 information. If you do not wish to have data transmitted, then you must
use a Free Place module in that slot.
Each of the two Analog Input Function Blocks can be set up to return Level, or Distance.
Within the function blocks, the values are scaled according to the user requirements
(please see
Analog Input Function Blocks 1 and 2
on page 116 for details).
Note: Each of the slots has to have a module defined in it.
1)
For more information, please see
Analog Input Function Blocks 1 and 2
on
page 116.