Delta RMC151 - Manual (Page 518)

RMC70/150 and RMCTools User Manual
• Do not change the Read/Write Request bit after a read request until you have
processed the data in the Read Response register.
• Do not change the read address or Read/Write bit when the Read/Write Request
bit does not match the Read/Write Acknowledge bit.
Write to the RMC70
To write to the RMC70, use the following steps:
• Wait until the Read/Write Request bit is equal to the Read/Write Acknowledge
bit. If they are not equal, the RMC70 is currently processing a read or write request.
• Copy the value you wish to write to the RMC70 into the Write Value register (7) of the
Command Block.
• Enter the Read/Write Address file and element. For example, for address %MD56.0,
the file is 56, and the element is 0. See RMC70 Register Map topic for a description of
all RMC70 registers and their addresses.
• Set the Read/Write bit.
• Toggle the Read/Write Request bit.
• Wait until the 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.
Note:
The RMC70 sets the Read/Write Acknowledge bit equal to the Read/Write Request to
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.
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
the initial data showed that the Command Request bit already was 1, which explains
why the command was not issued. The bit must be toggled to send a command, so he
should have written a 0.
498 Delta Computer Systems, Inc.