Universal Robots UR3/CB3 User Manual page 135

13.11 Installation MODBUS client I/O Setup
Here, the MODBUS client (master) signals can be set up. Connections to MODBUS
servers (or slaves) on specified IP addresses can be created with input/output signals
(registers or digital). Each signal has a unique name so it can be used in programs.
Refresh
Push this button to refresh all MODBUS connections.
Add unit
Push this button to add a new MODBUS unit.
Delete unit
Push this button to delete the MODBUS unit and all signals on that unit.
Set unit IP
Here the IP address of the MODBUS unit is shown. Press the button to change it.
Add signal
Push this button to add a signal to the corresponding MODBUS unit.
Delete signal
Push this button to delete a MODBUS signal from the corresponding MODBUS unit.
Set signal type
Use this drop down menu to choose the signal type. Available types are:
Version 3.3.3
• Digital input: A digital input (coil) is a one-bit quantity which is read from the
MODBUS unit on the coil specified in the address field of the signal. Function
code 0x02 (Read Discrete Inputs) is used.
• Digital output: A digital output (coil) is a one-bit quantity which can be set to
either high or low. Before the value of this output has been set by the user, the
value is read from the remote MODBUS unit. This means that function code 0x01
(Read Coils) is used. When the output has been set by a robot program or by
pressing the "set signal value" button, the function code 0x05 (Write Single Coil)
is used onwards.
• Register input: A register input is a 16-bit quantity read from the address speci-
fied in the address field. The function code 0x04 (Read Input Registers) is used.
• Register output: A register output is a 16-bit quantity which can be set by the
user. Before the value of the register has been set, the value of it is read from the
remote MODBUS unit. This means that function code 0x03 (Read Holding Regis-
ters) is used. When the output has been set by a robot program or by specifying
a signal value in the "set signal value" field, function code 0x06 (Write Single
Register) is used to set the value on the remote MODBUS unit.
II-51 CB3