MBS Protocol
PLX30 Series
User Manual
Ethernet and Serial Gateways
Page 130 of 200
ProSoft Technology, Inc.
September 19, 2012
Slave Configuration Parameters
Parameter
Value
Description
Minimum
Response
Delay
0 TO 65535
Specifies the number of milliseconds to wait before responding to a
command received on the port from a remote Master. This delay is
sometimes required to accommodate slower Master devices.
Internal
Slave ID
1 TO 247
Defines the virtual Modbus slave address for the port. Any
commands received on the slave port, addressed to the node
address entered here, will be processed by the gateway. Each slave
device on the network must be assigned a unique address.
Bit Input
Offset
0 to 3998
Specifies the internal database address to use as the zero address
or starting point for binary Input Status data. Input Status data is
read-only data, requested by Modbus Function Code 2 commands
(Read Input Status). For example, if this parameter is set to 150 and
a Function Code 2 command is received requesting Input Status
address 0 (virtual Modbus Address 10001 or 100001), the data
returned in the response will be the bit value at register 150, bit 0 in
the gateway's database.
Word Input
Offset
0 to 3998
Specifies the internal database address to use as the zero address
or starting point for Input Register (16-bit integer) data. Input
Register data is read-only data, requested by Modbus Function
Code 4 commands (Read Input Registers). For example, if this
parameter is set to 500 and a Function Code 4 command is
received requesting Input Register address 0 (virtual Modbus
address 30001 or 300001), the data returned in the response will be
the value at register 500 in the gateway's database.
Output
Offset
0 TO 3998
Specifies the internal database address to use as the zero address
or starting point for binary output Coil data. Coil data is read by
Modbus Function Code 1 commands (Read Coils) and written by
Function Codes 5 (Force Single Coil) or Function Code 15 (Force
Multiple Coils). For example, if this parameter is set to 50 and a
Function Code 1 command is received requesting Coil address 0
(virtual Modbus Coil address 00001 or 000001), the data returned in
the response will be the value at register 50, bit 0 in the gateway's
database.
Holding
Register
Offset
0 to 3998
Specifies the internal database address to use as the zero address
or starting point for Holding Register (16-bit integer) data. Holding
Register data is read by Modbus Function Code 3 commands (Read
Holding Registers) and written by Function Code 6 (Preset Single
Register) or Function Code 16 (Preset Multiple Registers).
For example, if this parameter is set to 1000 and a Function Code 3
command is received requesting Holding Register address 0 (virtual
Modbus address 40001 or 400001), the data returned in the
response will be the value at register 1000 in the gateway's
database.
End of
Message
Delay
0 to 65535
Specifies a time delay in milliseconds to be added to the 3.5
character time delay used by the module to recognize the end of a
message. Certain applications may require validation of Modbus
messages with more than 3.5 character time between consecutive
bytes (example: modem applications). A value of 0 will cause the
default end of message delay to be used.
