Communication Manual

Chapter 2 │System integration 7
When using Modbus TCP the controller Ethernet port in combination with TCP port setting 502
should be used.
Writing values
To override the output values, set the output to manual mode using a Modbus signal. Then set the
corresponding ..._ManSet signal to the wanted level. These signals are listed in Chapter 5: Holding
Registers. Remember that only values with a default value are adjustable, you will find these in the
chapters Coil Status Register and Holding Register.
Configuration
Modbus TCP/IP enabled as default. Modbus RTU is enabled via configuration of the communication
ports.
The communication parameters for the Modbus line is the most important thing to configure first.
These parameters must be identical in both the master unit and slave units, since they define the
structure of messages and the transmission speed.
The default configuration values of a Access controller are
Slave address: 1
Word length: 8 bit
Parity: none
Stop bits: 2 bits
Baud rate: 9600 bps
Slave address
A new Modbus slave address can be set for each air handling unit using the NaviPad.
NOTE To change the Modbus slave address when using Modbus TCP/IP a communication port must
be temporarily configured as Modbus slave to access the slave address setting.