Omron PRT1-SCU11 Operation Manual page 22

PROFIBUS-DP Gateway Unit
IBM compatible Personal
Computer
I/O Data
Special operations
Free Communication
Blocks
Troubleshooting
Functions
10
An IBM compatible Personal Computer is connected to the PROFIBUS-DP
Gateway Unit via a RS-232C serial communication to the auxiliary port. Appli-
cation programs running on the Personal Computer can through the auxiliary
port communicate with Compoway-F components, bypassing the PROFIBUS-
DP interface.
The data exchanged over PROFIBUS-DP are words, and represent either
fixed length communication blocks or free communication blocks. Fixed
blocks are predefined data-blocks of data, status data is read from and control
data is written to each temperature controller or R88A-MCW151-E unit. These
fixed blocks are defined in the Unit and cannot be changed by the user, the
most commonly used way to exchange data between a Master and the Unit.
On the other hand there are Free Communications Blocks which allow the
user to send any Compoway-F read, write or operate instruction to a attached
device without unit interference.
PROFIBUS limits the total number of input and output words in one message
to 244 bytes. PROFIBUS does not allow the sum of input and output words to
exceed this limit. The PROFIBUS-DP Gateway limits the total number of input
words to 200 words, and the total number of output words to 200 words, but
the actual sum for one unit can not exceed the 400 words limit.
Easy specifying and sending of Compoway-F operation commands to change
the mode of the configured temperature controllers.
The PROFIBUS-DP Gateway Unit supports Free Communication Blocks
(FCB) data exchange with the Master. Three types of FCB's are defined, the
types are Operate, Read and Write.
• Operate: execution of any operation command which is defined in a tem-
perature controller.
• Write: execution of any one-element write command of parameters
defined in a temperature controller.
• Read: execution of any one-element read command of parameters
defined in a temperature controller.
The PROFIBUS-DP Gateway Unit supports cyclic Master - Slave communica-
tions, called data exchange mode. In data exchange mode the Unit:
• retrieves all data from the attached units (Compoway-F or Host Link)
according to the PROFIBUS configuration and stores this data in the
PROFIBUS input buffer. All input data is obtained before the data is sent
to the PROFIBUS Master as input data.
• writes all data from the PROFIBUS outputs to the attached units accord-
ing to the PROFIBUS configuration, but only if the data received from the
Master differs from the current value in the units.
• Send special operation commands.
• according to the PROFIBUS configuration FCB: the command data is first
obtained from the PROFIBUS output data (received from the Master) and
next the command is sent to the addressed unit. The command response
is returned to the Master as PROFIBUS input data.
The PROFIBUS-DP Gateway is provided with a variety of troubleshooting
functions for prompt recovery in case of errors:
• Extensive self-diagnostic function at startup
• Diagnostics information is sent to the PROFIBUS Master unit in case:
• One or more units attached to the PROFIBUS-DP Gateway Unit have
a communication error.
• The PROFIBUS-DP Gateway Unit has a system error.
Section 1-3