Hardy HI 2151/30WC Single-Scale Controller - Manual (Page 33)

Section 5: Block Writes
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Section 5 Block Writes
5.1 SCOPE
Chapter 5 covers block write commands for the PROFIBUS Interface Option.
Programmers and other users be familiar with this chapter before operating the PROFIBUS
Interface Option.
5.2 OVERVIEW OF TRANSFER COMMANDS
1. PROFIBUS Interface Card maximum buffer size 112 byte buffer
2. Siemens PLC
a. TI 505 Series PLC
Requires the Field Interface Module (FIM) to communicate over PROFIBUS.
Can continually exchange up to 32 words or 64 bytes for both server input
and output with each client device.
b. S5 Series PLC
Requires IM 308C Module to communicate over PROFIBUS.
Can continually exchange up to 244 bytes for server input and output with
each client device.
c. S7 Series PLC
PROFIBUS ready, does not require additional modules.
Can Continually exchange up to 244 bytes for server input and output with
each client device.
3. Allen-Bradley PLC5 Series
a. Requires PROFIBUS DP module to communicate over PROFIBUS.
b. Can continually exchange up to 244 bytes for both server Input and Output with
each client device.
5.3 OVERVIEW OF BLOCK TRANSFER COMMANDS
PLC
LADDER LOGIC
PROGRAM
WRITE/READ
#5400 (hex) +
BLOCK READ
DATA NUMBER RESPONSE
# BETWEEN
14-20 or #23 (hex) +
DATA REQUESTED
DATA EXCHANGE
BLOCK TRANSFER
1. It is important to keep in mind that the amount of bytes that can be
transferred is determined by the server not the PROFIBUS
interface option.
2. When using the HI 2151 Series Weight Controller PROFIBUS
interface, the user can select the Block Read Data and Block Write
Commands as required. However, the amount of bytes that can be
transferred is dependent on the data transfer capability of the
server being used.
3. The ladder logic program provides the server with the ability to
read and write weight data by referencing the PROFIBUS address,
the byte numbers and number of bytes.