MAV421, 422 Modules with 4-20mA output

MAV421: externí modul analogového výstupu 4-20mAExternal modules MAV421 and MAV422 are RS485 converters under the FINET protocol to galvanically separated active current outputs 4-20 mA or 0-20 mA. The MAV421 module has 1 current output I1, the MAV422 module contains 2 current outputs I1 and I2.

Examples of use

  • Extension of the number of analog outputs in control systems
  • Transfer of measured values to the superior system
  • Control of frequency converters and servo valves; continuous control of machines

Characteristic properties

  • 1 or 2 active current outputs 4-20 mA or 0-20 mA
  • Galvanic separation of outputs from supply voltage and RS485 serial line
  • An accurate 16-bit converter ensures high accuracy of the output signal
  • Possibility of supplying external supply voltage for analog outputs
  • FINET and FINET_SO protocols, adjustable address in the range 121 to 136
  • Integrated overvoltage protection of inputs and outputs
  • Supply voltage in the range of 12 to 24 V DC
  • Mechanical adaptation for DIN rail installation, width 2 standard modules

Output current and communication protocol settings

After opening the upper lid of the box, 2 configuration switches are made available.

MAV421: externí modul analogového výstupu 4-20mA

Location of setting switches and connection of terminals of MAV421 and MAV422 modules


Position No. 1 of the double smaller switch located at the right side of the box is used to set the required current output:

1-OFF    current output 4-20 mA

1-ON     current output 0-20 mA


Position No. 2 (at the box wall) of this switch is used to select the communication protocol:

2-OFF    FINET_SO protocol, communication speed 2400Bd/8/N/1 (do not use with H7)

2-ON      FINET protocol, communication speed 19200 Bd, 1 stop bit, no parity

Connection to the superior control unit via RS485

By default, each module has the basic communication address ADR = 121 set. The user can use a larger quadruple switch on the module board to set 16 combinations in the range 0 to 15, which are added to the basic communication address 121. The combination is set binary, ie as the sum of the weights of the individual closed bits 1, 2, 4 and 8.

If two MAV421 or MAV422 modules are to have identical current outputs, it is not possible to set one identical communication address for them, but each module must be controlled by a separate channel from the control unit using two different communication addresses.

In the extreme case, up to 2x 16 MAV421 or MAV422 modules, ie up to 64 current outputs (applies to MAV422), can be connected to one H7 control unit via two RS485 buses. For the M4016, it is half (it has one RS485 bus).

Mechanical design

The module is adapted for mounting on a 35mm DIN rail and has the width of two standard modules. The module signals the power supply status, the output current loop and communication with the M4016 unit by the LED lights.

Power supply

The supply voltage for the MAV 420 / DIN can range from 12 to 24V DC, either from the M4016 unit or from another, separate, external source.

Example of connecting I / O modules to the H7 unit


Technické parametry




 1x 4(0)-20 mA

2x 4(0)-20 mA

Output error  

<± 0.05% of range, accurate 16 bit converter

Overrun speed  

<0.5 s over the entire range

Load resistance 

< 500 Ω

Output RS485 

Channels K1, K2 on RS485, FINET protocol

Com. address 

120 + on-board switch (0 to 15)

Power voltage 

12 to 16 V DC / I < 50 mA

12 to 16 V DC / I < 80 mA

Temperature range 

-25 °C to +60 °C

Dimensions / IP 

109 x 25 x 57 mm /IP 20 (width 2 modules, DIN rail)

Price list