Universal Robots e Series User Manual page 202

Sequential mode
Available only when Show Advanced Options (see 16.4.1) is selected. Selecting this checkbox forces
the modbus client to wait for a response before sending the next request. This mode is required by
some fieldbus units. Turning this option on may help when there are multiple signals, and increasing
request frequency results in signal disconnects. Note that the actual signal frequency may be lower
than requested when multiple signals are defined in sequential mode. Actual signal frequency can
be observed in signal statistics (see section 16.4.1). The signal indicator will turn yellow if the actual
signal frequency is less than half of the value selected from the "Frequency" drop-down list.
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:
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 specified 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 Registers) 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.
Set signal address
This field shows the address on the remote MODBUS server. Use the on-screen keypad to choose
a different address. Valid addresses depends on the manufacturer and configuration of the remote
MODBUS unit.
Set signal name
Using the on-screen keyboard, the user can give the signal a name. This name is used when the
signal is used in programs.
e-Series II-112
16.4 Fieldbus
Version 5.4