Delta RMC151 - Manual (Page 572)

RMC70/150 and RMCTools User Manual
Data Table Address: Enter the address of the first Allen-Bradley PLC
register to read RMC registers into, or to write to RMC registers from.
Size in Elements: Enter the number of RMC registers to read or write in this
field.
Target Device: This section holds parameters for the target device.
Message Timeout: Indicate the number of seconds to wait for the RMC to
respond before determining that the attempt failed. This can be set as low
as a few seconds.
Data Table Address: Enter the address of the first RMC register to read or
write in this field. See the Registers Maps topic for help on addresses.
Local / Remote: Choose Local.
Routing Information File (RI): Enter the address in the Routing
Information File that you intend to use (e.g. RI10:0).
3. On the Multi-hop tab, in the To Address box, enter the IP address of the target
RMC. For example, 192.168.0.219.
Using the MSG Block in Ladder Logic
The Allen-Bradley MSG block takes multiple ladder scans to complete. Therefore, it is
important to enable the MSG block for the correct amount of time. Specifically, the MSG
block must be energized until the message control's enable (EN) bit turns on. Delta has
found some aspects of this to be difficult and therefore has provided the following ladder
samples:
Read or Write Continuously
Using the Examine If Open instruction as shown below fulfills two requirements of
continuous MSG transactions. First, it will keep the block energized until the EN turns on,
and second, it de-energizes the MSG block once the transactions is started so that when
the transaction is completed (EN goes low again), the MSG block sees a rising edge on its
input, thus repeating the transaction:
Read or Write Once
This sample takes care to keep the MSG block energized until the MSG block starts, as
indicated by the enable (EN) bit turning on. Once this happens, the application-controlled
TriggerOnce coil is turned off. The message control's Done (DN) or Error (ER) bits can be
used to process the results of the transaction.
552 Delta Computer Systems, Inc.