MB40 & MB45 MODBUS TCP/IP Gateway
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Below the current communications statuses is a web form with provision to set the TCP/IP settings
of the MB40. The form fields will be populated with the Gateway’s current values. These can be
altered and written to the MB40.
After writing these values, you will likely want to change TCP switch 1 to read from memory on the
next power up, otherwise the TCP/IP configuration will read from the switches.
Configuration Using Modbus (RTU or TCP/IP)
The MB40 has 13 Modbus holding registers reserved for configuration. These settings can be read
and written using either serial Modbus (RTU on RS485) or Modbus TCP/IP.
Table 10: Modbus TCP/IP Configuration Registers
Modbus Register
Function
256
1st octet IP Address
257
2nd octet IP Address
258
3rd octet IP Address
259
4th octet IP Address
260
1st octet Subnet Mask
261
2nd octet Subnet Mask
262
3rd octet Subnet Mask
263
4th octet Subnet Mask
264
1st octet Default Gateway
265
2nd octet Default Gateway
266
3rd octet Default Gateway
267
4th octet Default Gateway
268
Commit to Gateway (write a 1)
Each register holds one octet of the TCP/IP configuration. These can be read to view the current
TCP/IP settings, or written to set the values. Once all twelve octets are manually set, the settings are
committed to the gateway by writing a one to holding register 268. Make sure
all
registers are
written with correct values before they are committed to the gateway.
