PLX3x Series ♦ Multi-Protocol Gateways
MBS Protocol
User Manual
ProSoft Technology, Inc.
Page 123 of 215
January 25, 2018
MBS Slave Configuration Parameters
Parameter
Value
Description
Minimum
Response Delay
0 to 65535
Specifies the number of milliseconds the gateway waits before
responding to a command received on the port from a remote Master.
This delay may be required to accommodate slower Master devices.
Internal Slave ID
0 to 247
Specifies the virtual Modbus slave address for the port. The gateway
processes any commands received on the slave port, addressed to this
address. Each slave device on the network must have a unique address.
Bit Input Offset
0 to 3998
Specifies the internal database address for 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 you set this parameter to 150 and a Function Code 2
command is received requesting Input Status address 0 (virtual Modbus
Address 10001 or 100001), the gateway returns the bit value at register
150, bit 0 in the gateway's database.
Word Input Offset 0 to 3998
Specifies the internal database address for 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 you set this parameter to 500 and a Function Code 4
command is received requesting Input Register address 0 (virtual
Modbus address 30001 or 300001), the module returns the value at
register 500 in the gateway's database.
Output Offset
0 to 3998
Specifies the internal database address for 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 you set this parameter to 50 and a Function Code 1
command is received requesting Coil address 0 (virtual Modbus Coil
address 00001 or 000001), the gateway returns the value at register 50,
bit 0 in the gateway's database.
Holding Register
Offset
0 to 3998
Specifies the internal database address to for 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 you set this parameter to 1000 and a Function Code 3
command is received requesting Holding Register address 0 (virtual
Modbus address 40001 or 400001), the gateway returns 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 that the gateway uses 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 (for example,
modem applications). A value of 0 causes the gateway to use the default
end of message delay.
