Delta RMC151 - Manual (Page 549)

6 Communication
• Do not change the Read/Write bit, write address, or write value when the
Read/Write Request bit does not match the Read/Write Acknowledge bit.
Note:
The RMC70 sets the Read/Write Acknowledge bit equal to the Read/Write Request to
the acknowledge that the write was processed. In addition, the RMC70 also places the write
value in the Read Response register. This provides a simple method of verifying that the write
was completed.
Write to Any Contiguous RMC70 Registers
To write to any contiguous RMC70 registers, use Command Block registers 8-15 and
Response Block register 16.
To write to the RMC70, use the following steps:
• Wait until the Command Block register 8 Read/Write Request bit is equal to the
Response Block register 16 Read/Write Acknowledge bit. If they are not equal, the
RMC70 is currently processing a read or write request.
• Set the Command Block register 8 Read/Write bit.
• In the Command Block register 8, set the Read/Write Address File and Read/Write
Address to the first RMC70 address you wish to write to. For example, for address
%MD56.0, the file is 56, and the element is 0. Set the Count to the number of register
to write, up to 7. For a description of all RMC70 registers and their addresses, see the
RMC70 Register Map topic.
• In the Command Block registers 9-15, put the values you wish to write.
• Toggle the Read/Write Request bit.
• Wait until the Read/Write Request bit is equal to the Read/Write Acknowledge
bit. When they are equal, the RMC70 has received the data written to it.
To further clarify the ordering, keep these basic rules in mind:
• Do change the Read/Write bit, write address, and write value before toggling the
Read/Write Request bit.
• Do not change the Read/Write bit, write address, or write value when the
Read/Write Request bit does not match the Read/Write Acknowledge bit.
Debugging
Using the Event Log for PROFIBUS
The Event Log can record every change in the PROFIBUS data received by the RMC75P.
This is the data in the Command Block. It does not record the data in the Response Block,
which is sent by the RMC75P. The Event log displays the received data in hexadecimal
format.
The Event Log can log an entry when any of the following occurs:
• Data is Initialized
(the Configuration Information box must be checked in the Event Log filter for
PROFIBUS)
This typically occurs when the RMC70 is restarted. The Event Log entry will be labeled
initial data. It provides the user with a reference of what the initial data is.
For example, assume a user wrote a 1 to the Command Request bit to issue a
command immediately after starting the PROFIBUS communications, but the
command was not issued. The user then looked in the Event Log and found out that
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