The AD-AEB 20 GX enables 2-channel analog signal acquisition while providing digitally processed process variables. The signals are provided via an RS485 bus interface. Analog values ??and scaling values ??can be called up via implemented MODBUS commands. All settings regarding scaling or filters are made via MODBUS commands.
The power supply and the RS485 bus connection are possible via the rear DIN rail connector. The device is equipped with two rotary coding switches with which the bus address can be set on the device.
The input current shunt is automatically switched on when reading the current value. With the input signal switches (E1 / E2), each signal input can be permanently connected to the 50 Ohm terminating resistor in order to safely complete current loops even if the supply voltage fails.
The operating voltage is indicated by a green LED. The data communication is signaled by a yellow LED. Invalid measurement signals outside the defined measuring range are detected. In this case, the green LED flashes.
As well as interface settings as well as the device address can be modified during operation by means of Modbus commands. All Modbus register addresses and associated commands are listed in the document attachment.



Conversion of analog process variables in digital information, already in the cabinet. Drastic reduction of wiring work.

Specific characteristics

  • Two analogue inputs can be used as voltage or current input
  • Adjustable filter function
  • Galvanically isolated RS485 bus interface
  • Parameterizable interface settings
  • Hardware switch for device address
  • Galvanically isolated switching power supply
  • Can be parameterized with PC via AD Studio configuration software
  • Status LED for operating voltage and data communication
  • Visual display for invalid measuring signals
  • Modbus master mode

Business data

Order number
Rail connector
Customs tariff number / country of origin 8543 70 90 / Deutschland


Data sheet pdf en-aeb20gx.pdf (213 kB)
Tender text zip (10 kB)
Safety instructions pdf ad-safety-instructions.pdf (43 kB)

Technical specifications

Current inputs
Measuring range 0 ... 20 mA
Input resistance 50 Ohm
Voltage inputs
Measuring range 0 ... 10 V
Input resistance 100 kOhm
Signal detection
Channel counts (U/I) 2
Basic accuracy < +/- 0,3 %
Temperature influence 80 ppm/K
Sampling rate / resolution 100 ms / 10 bit
Transmission behaviour
Response time Max. 15 ms
Software protocol Modbus-RTU
Data format 19200, e, 8, 1
Max. bus users 99
Bus termination 120 ohms both sides at the end
Max. length of bus 500 m (no spur lines)
Cable Twisted and shielded
Supply voltage 18 ... 30 V DC
Max. power consumption 600 mW (24V DC)
Dimensions (WxHxD) 6,2 x 92 x 101 mm³
Manner of fastening DIN rail mounting 35mm, EN 50022
Type of protection IP 20
Connection method Screw clamp
Bolting torque terminals 0,5 Nm
Wire cross section Max. 2,5 mm2
Weight ~ 70 g
Environmental conditions
Permissible ambient temperature -10 ... +50 °C
Storage and transport -10 ... +70 °C (no condensation)
Product family standard 1) EN 613261
Emission 2) EN 55011, CISPR11 Cl. A, Gr. 1
1) During checking, slight signal deviations are possible.
2) Warning:
This device is not intended to be used in residential areas and can not ensure adequate protection of radio reception in such environments.
Electrical safety requirements
Product family standard EN 61010-1
Galvanic isolation, test voltages
RS485 bus / power supply 1,5 kV, 50 Hz (1 min)
Analog inputs / power supply 1.5 kV, 50 Hz (1 min)
Analog input / RS485 bus 1,5 kV, 50 Hz (1 min)
Analog inputs between themselves 0 kV
Protection circuits
Power supply Electrical surge and reverse current protection

Block and wiring diagram




CAD / CAE Daten

CAD model is not yet available for this product.

The CAD product overview can be found at:

Display and operating elements

Designation LED Meaning
On green Power supply
D yellow RS485 Communication
RS485 Address switch(01...99)
E1 Input signal switch (U/I) channel 1
E2 Input signal switch (U/I) channel 2

Modbus Communication

The AD-AEB 20 GX contains a RS485 bus interface on which the Modbus RTU protocol is used. All control functions of the device can be executed via this bus interface. The preset standard data format is 19200,e,8,1. Adaptation to a different data format is possible at any time. The bus address (1...99) is set to the side-mounted rotary switches. The address 0 is not permitted for the bus operation. However, on this zero position the device is accessible only via the standard data format (19200, e, 8.1). The position 0 thus represents a service position (slaveaddress = 0), the example can be used during parameterization error.

The AD-AEB 20 GX supports two Modbus functions. These are the functions "Read Holding Registers" (0x03) and "Write Holding Registers" (0x10). With the "Read Holding Registers" function data can be read from the device and written with "Write Holding Registers" data. The individual register width is 16 bits. Please see the Modbus specification for detailed explanations of the Modbus communication. This is online available for free and can be downloaded from the Adamczewski homepage.

The following Modbus data are accessible via the RS485 bus:

Start address Reg. number Name Datatype [Code] = Value read write
40501 1 Address switch U16 1...99...247 yes yes
40502 1 Flashing function U16 0/1...255 yes yes
42905 1 Signal input type 1 U16 U=0 / I=1 yes yes
42906 1 Signal input type 2 U16 U=0 / I=1 yes yes
40211 1 Damping U/I 1 U16 0...1000 s yes yes
40212 1 Damping U/I 2 U16 0...1000 s yes yes
43001 2 In signal begin U/I 1 FLOAT V / mA yes yes
43003 2 In signal end U/I 1 FLOAT V / mA yes yes
43005 2 Scale begin 1 FLOAT -99999 ... yes yes
43007 2 Scale end 1 FLOAT ... 99999 yes yes
43009 2 In signal begin U/I 2 FLOAT V / mA yes yes
43011 2 In signal end U/I 2 FLOAT V / mA yes yes
43013 2 Scale begin 2 FLOAT -99999 ... yes yes
43015 2 Scale end 2 FLOAT ... 99999 yes yes
40901 2 Analog intput U1 FLOAT 0...10V yes no
40903 2 Analog intput I1 FLOAT 0...20mA yes no
40905 2 Analog intput U2 FLOAT 0...10V yes no
40907 2 Analog intput I2 FLOAT 0...20mA yes no
40909 2 Scaled value 1 FLOAT Begin ... End yes no
40911 2 Scaled value 2 FLOAT Begin ... End yes no
42901 1 Baud rate U16 Index, see list below yes yes
42902 1 Parity U16 [0]=even; [1]=odd; [2]=no yes yes
42903 1 Modbus Master U16 0/1 yes yes
49102 1 Device reset U16 0 no yes
49105 6 Device type String AEB20GX yes no
49119 1 Firmware version U16 MSB/LSB yes no

Coding baudrate list
Index 0 1 2 3 4 5 6 7 8 9
baud 2400 4800 9600 14400 19200 28800 38400 57600 76800 115200

After changing the interface parameters, a device reset is required.

Modbus master mode
The device can even work in Modbus master mode to transfer data between any devices within an RS485 line.
For Modbus master operation, starting with Modbus register 40611, there are 38 consecutive data transfer sets,
with 5 configuration registers each.

Start address Reg. number Name Datatype [Code] = Value read write
40611 1 Source address [1] U16 1...99 yes yes
40612 1 Source register [1] U16 nnnnn yes yes
40613 1 Target address [1] U16 1...98 yes yes
40614 1 Target register [1] U16 nnnnn yes yes
40615 1 Register count [1] U16 1/2 yes yes
40796 1 Source address [38] U16 1...99 yes yes
40797 1 Source register [38] U16 nnnnn yes yes
40798 1 Target address [38] U16 1...98 yes yes
40799 1 Target register [38] U16 nnnnn yes yes
40800 1 Register count [38] U16 1/2 yes yes

For the Modbus master mode, the parameter "Modbus master" must be activated and the address switch set to position 99.
Data transfer begins six seconds after activation or device restart.
A flashing green LED indicates a communication error.

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