Universal Robots UR3/CB3 User Manual (English)

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13.11 Installation → MODBUS client I/O Setup

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.

ﬁeld. The function code 0x04 (Read Input Registers) is used.

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.

Signal value

Here, the current value of the signal is shown. For register signals, the value is expressed as an

unsigned integer. For output signals, the desired signal value can be set using the button. Again,

for a register output, the value to write to the unit must be supplied as an unsigned integer.

Signal connectivity status

This icon shows whether the signal can be properly read/written (green), or if the unit responds

unexpected or is not reachable (gray). If a MODBUS exception response is received, the response

code is displayed. The MODBUS-TCP Exception responses are:

E1: ILLEGAL FUNCTION (0x01) The function code received in the query is not an allowable action

for the server (or slave).

E2: ILLEGAL DATA ADDRESS (0x02) The function code received in the query is not an allowable

action for the server (or slave), check that the entered signal address corresponds to the setup

of the remote MODBUS server.

CB3 II-52 Version 3.10

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Universal Robots UR3/CB3 Specifications

General

Payload	3 kg
Reach	500 mm
Degrees of Freedom	6
IP Rating	IP54
Repeatability	±0.1 mm
Power Supply	100-240 VAC, 50-60 Hz
Protection Class	IP54
Weight	11 kg
Base Footprint	128 mm diameter
Max Speed	1 m/s
Programming Method	Graphical programming interface
Communication Interface	Ethernet
Safety Standards	EN ISO 10218-1
Operating Voltage	24 VDC