Delta RMC151 User Manual

Page 517

6 Communication

Action

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.

Last Deferred: This command and any deferred commands in the

PROFIBUS command buffer are executed simultaneously.

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.

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 from the RMC70
The Response Block only returns the values from 8 registers, which must be determined

when setting up the communications. However, it is possible to set up one of the

registers 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 RMC, 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.

•

Clear the Read/Write bit.

•

Set the Read/Write Address File and Read/Write Address Element. For example, for

address %MD8.12, the file is 8, and the element is 12. See the RMC70 Register Map

topic for a description of all RMC70 registers and their addresses.

•

Toggle the Read/Write Request bit.

•

Wait until the Read Request bit is equal to the Read/Write Acknowledge

bit. When they are equal, the RMC70 will have updated the Axis 0 Read Response

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.

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This manual is related to the following products:

RMC150 RMC70