Using Mstr Block To Change Modbus Plus Address; Modbus Plus Node Address Software Change (385/485 ); Mstr Format - Black & Decker d984 Installation Manual

When the Mem/DefaultiModem DIP switch is in the MEM position the bridge mode
can also be enabled or disabled by using the panel software " Offline" ' Configura-
tion" " PORTS' Bridge subfunction.
Using MSTR Block To Change Modbus Plus Address
You setup the MSTR block by transitioning the enable input ON for one scan.
The MSTR function Done output passes power in the same scan (assuming no er-
rors). There will be a delay of up to IO seconds in the availability of the newly ad-
dressed Controller due to the time required fully implement the change including
m-initializing the link.
If you hold the MSTR block enabled for more than one scan, the Change Address
Command is issued for each scan so enabled. This results in a race condition
locking the controller out of effective operation.
Part of the process of implementing the Change Address Command allows testing
for:
If the specified address equals 0
If the specified address is greater than 64
If the specified address is equal to the current address.
In each true case the PEER Processor ignores the Change Address Request but
remains available to the host processor.
Modbus Plus Node Address Software Change (385/485 ONLY)
The on board dip switches as shown in Figure 13 are read by the PEER PLC at
power-up to determine what the Node address is. This setting stays in effect until
a power-cycle with new settings or a software controlled " Change Address Com-
mand" is issued to the PEER PLC. The Ladder Logic implemented MSTR Block is
the mechanism by which you issue the proper command.
cl7
Note The Controller in which you want to change the Node address
must be running.
MSTR Format
You can issue the " Change Address Command" using the ladder logic MSTR DX
block. Figure 14 is an example of a Modsoft screen with MSTR block.
GM-0984~EDK
System Planning 35