Delta RMC151 - Manual (Page 535)

6 Communication
7. Wait until the Command Request bit is equal to the Command Acknowledge
bit. When they are equal, the RMC70 has received the command.
NOTE:
Until the Command Acknowledge bit matches the Command Request bit, the Input Data
registers, including the Status Bits registers, do not reflect having received the command.
Example
A Move Absolute (20) command is issued using the PROFIBUS Command Block. Until the
Command Requestbit matches the Command Acknowledgebit after the Command
Requestbit has been toggled, the In Positionbit should not be checked as it may still be set
for the previously requested move. Once the Acknowledgetoggles to match, the In
Positionbit will have been cleared and when it is set, it is due to the new command being
complete. Similar synchronization issues are resolved in the same way with other status bits
and registers.
Issue Simultaneous Commands
Although only one command may be sent at a time to the RMC75P via PROFIBUS, it is
possible to simultaneously issue different commands to several axes by using deferred
commands. Deferred commands are stored in the PROFIBUS command buffer until all
deferred commands are received. They are then executed simultaneously. Bits 30 and 29
in the Command Data Register of the Command Block define the deferred status of each
command issued. The bits are used as follows:
Bit
30 Bit
29
Action
0 0 Single Command: When both bits are zero, the command is not
deferred. The command is executed normally. If the PROFIBUS command
buffer contains any commands, an error is logged in the Event Log and
the commands are removed from the command buffer without being
executed. The new command is still issued.
0 1 Last Deferred: This command and any deferred commands in the
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
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