MBS Protocol
PLX3x Series ♦ Multi-Protocol Gateways
User Manual
Page 132 of 215
ProSoft Technology, Inc.
January 25, 2018
Master Port: Modbus Slave List Status
The gateway stores
Slave List Status
values for each Master port in the address
locations specified in the following table. Note that all the status values are
initialized to zero (0) at power-up, cold boot and during warm boot.
Modbus Port
Address Range
1
4510 to 4764
2*
4910 to 5164
3*
5310 to 5564
4*
5710 to 5964
*Status data for Ports 2 through 4 is only present in 4-port MBS gateways.
Warning: None of these addresses are available in the Modbus address range. In order to access
this data through a Modbus request, you must move the data into the 0 to 3999 address range.
See Mapping Data in Module Memory (page 24).
Port 1 Slave List Status Layout
The addresses listed are for Port 1 only; but the format is the same for each port.
See Master Port: Modbus Slave List Status (page 132) for the start address for
each port.
Internal
Database
Address
(Example)
Offset
Description
4510
0
Slave #1 Status
4511
1
Slave #2 Status
4512
2
Slave #3 Status
4513
3
Slave #4 Status
4514
4
Slave #5 Status
.
.
.
.
The slave status list contains the current poll status of each slave device on a
master port. Slaves attached to a master port can have one of three states.
Status
Description
0
The slave has is not defined in the command list for the master port and is not polled
from the Command List.
1
The slave is configured to be polled by the master port and the most recent
communication attempt was successful.
2
The Master port failed to communicate with the slave device. Communication with the
slave is suspended for a user-defined period based on the scanning of the command list.
