Delta RMC151 - Manual (Page 547)

6 Communication
PROFIBUS command buffer are executed simultaneously.
1 0 First Deferred: This command is placed as a deferred command in the
PROFIBUS command buffer, but is not otherwise processed. If the
command buffer already contains commands, an error is logged in the
Event Log and the commands are removed from the command buffer
without being executed. The new deferred command is still placed in the
command buffer.
1 1 Middle Deferred: This command is placed as a deferred command in the
PROFIBUS command buffer, but is not otherwise processed. This
deferred command type allows other deferred commands to be in the
command buffer, although they are not required to be there. Note that
for a 2-axis controller, this deferred setting will not be used because
there can only be a first and last deferred command.
Multiple deferred commands cannot be issued to the same axis. That is, if a deferred
command is issued to an axis that already has a deferred command, an error is logged in
the Event Log and the previous command is overwritten without being executed.
Read Any Single RMC70 Register
Registers 0-15 of the Response Block return the values from 16 registers, which must be
determined when setting up the communications. However, it is possible to set up one of
the registers 1-7 in the Response Block to return the value of a read from any single
register in the RMC70.
When a read is requested from any single register in the RMC70, the response from this
single-register read will be placed in the Axis 0 Read Response register. In order to see
the response from the PROFIBUS, you must map the Axis 0 Read Register into one of the
Indirect Data Map registers.
Notice that the copy from the requested register into the Axis 0 Read Response register
only occurs once, and therefore you will not see the value continuously updating like the
other Response Block registers.
To read any single register from the RMC70, use the following steps:
• Wait until the Response Block register 0 Read/Write Request bit is equal to the
Command Block register 6 Read/Write Acknowledge bit. If they are not equal, the
RMC70 is currently processing a read or write request.
• Clear the Command Block register 6 Read/Write bit.
• Set the Command Block Register 6 Read/Write Address File and Read/Write Address
Element. For example, for address %MD8.12, the file is 8, and the element is 12. For
a description of all RMC70 registers and their addresses, see the RMC70 Register Map
topic.
• 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 will have updated the Axis 0 Read Response
register with the requested data, and the corresponding Response Block register.
To further clarify the ordering, keep these basic rules in mind:
• Do change the read address and Read/Write bit before toggling the Read/Write
Request bit.
• 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.
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