Hardy HI 2151/30WC Single-Scale Controller - Manual (Page 8)

HI 2151 Series Weight Controller
Profibus Interface Option
2
1.5. PROFIBUS-DP CAPABILITIES
1.5.1 Watch Dog
Watch Dog communication control detects failures in the bus or the assigned DPM1 (DP-
Master - Class 1, which is the central controller in PROFIBUS-DP). If the interface card
detects no successful data transfers within a set interval, it switches its outputs to the fail-
safe state until successful communication is resumed.
1.5.2 Configuration
Configuration data contains the range of input and output areas and the information about
the data consistency (byte or word length).
The default configuration for Hardy PROFIBUS Interface is 16 words or 32 bytes.
For the 32 byte I/O the identifier bytes have the following format:
Number of Configuration bytes: 2
•
Config byte 1 77 (hexadecimal)
• Config byte 2 77 (hexadecimal)
The maximum number of bytes of I/O can be achieved by setting:
Number of Configuration bytes: 4
•
Config byte 1 7D (Hex)
• Config byte 2 7D (Hex)
• Config byte 3 7D (Hex)
• Config byte 4 7D (Hex)
For 112 bytes of input and 112 bytes of output.

NOTE: See DIN Standard 19245, Part 3, Paragraph 8.3.5, page 55, for a description of the config
data .
1.5.3 DATA EXCHANGE
The PROFIBUS Interface Option can exchange the Input (Read) and Output (Write) data
between devices. The PROFIBUS inputs and outputs are either selectable or block reads.
The PROFIBUS Interface Option supports the standard 16-word or 32-byte format for
transfers, but you can set it to any buffer size that is less than or equal to 112 bytes.
PRE-DEFINED BLOCKS ARE UP TO 32 BYTES IN LENGTH. IF LESS THAN 32
BYTES ARE DESIRED FOR BUS TRAFFIC CONSIDERATIONS, THEN
SELECTABLE TRANSFERS SHOULD BE USED.

NOTE: Two bytes equal one word.
1.5.4 DIAGNOSTICS
The PROFIBUS Interface Option has built-in diagnostics. Write command errors set
diagnostic bits, e.g. the NACK (not acknowledge) bit.