Example 1: Read Parameters - Siemens SINAMICS S120 Installation And Start-Up Manual

Communication via PROFIBUS
Acyclic communication
4.4.4

Example 1: read parameters

Requirements
1. The PROFIBUS master has been commissioned and is fully operational.
2. PROFIBUS communication between master and slave is operational.
3. The master can read and write data sets in conformance with
PROFIBUS DPV1.
Task description
Following the occurrence of at least one fault (STW1.3 = "1") on drive 2, the active
fault codes must be read from the fault buffer r0945[0] ... r0945[7].
The request is to be handled using a request and response data block.
Basic procedure
1. Create a request to read the parameters.
2. Invoke the request.
3. Evaluate the response.
Procedure
1. Create the request.
Parameter request
Request header
Parameter address
Information about the parameter request:
S Request reference:
The value is selected at random from the valid value range. The request
reference establishes the relationship between request and response.
S Request ID:
01 hex –> This identifier is required for a read request.
4-132
Request reference =
25 hex
Axis = 02 hex
Attribute = 10 hex
Parameter no. = 945 dec
Subindex = 0 dec
SINAMICS S120 Installation and Start-Up Manual, 12/04 Edition
Request ID = 01 hex
No. of parameters =
01 hex
No. of elements = 08 hex
E Siemens AG, 2004. All rights reserved
Offset
0 + 1
2 + 3
4 + 5
6
8