Modbus Serial Module for CompactLogix L1 and Point I/O Adapters ILX34-MBS232


ProSoft Technology’s ILX34-MBS232 module is ideal for point to point applications with a maximum distance of 50 feet away (15.2 meters) your processor. These include SCADA and field device interface applications. The module can be used in CompactLogix L1 processors or  Distributed 1734 Point I/O systems. In addition, the module can be configured as a Master or Slave.


Click on image(s) to enlarge
Drag with the mouse. Click for close.

Features and Benefits

  • Add-on Instruction creates UDTs, providing logical definitions for I/O, status, and control data
  • Diagnostic data available in RSLogix 5000/Studio 5000 controller tags, allowing decisions to be made based upon node health
  • Module configuration is backed up in the CompactLogix project (ACD file)
  • The serial port can be enabled or disabled through ladder logic
  • Supports up to 1,000 words of data
  • Supports up to 30 Modbus Commands & up to 36 words per command
  • The serial port can be configured as a Modbus Master or Modbus Slave device
  • Suitable for SCADA and field device interface applications


General Specifications - Modbus Master/Slave

Configuration Environment

RSLogix 5000/Studio 5000

Communication parameters

Baud Rate: 2400, 4800, 9600, 19200, 38400
Stop Bits: 1 or 2
Data Size: 7 or 8 bits
Parity: None, Even, Odd

Modbus Modes

RTU mode (8-bit data size only)

ASCII mode with LRC error checking

Node Address

1 to 247

Modbus Function Codes Supported

1: Read Coil Status
2: Read Input Status
3: Read Holding Registers 
4: Read Input Registers 
5: Force (Write) Single Coil 
6: Preset (Write) Single Holding Register 
8: Diagnostics (Slave Only, Responds to Sub function 00)

15: Force( Write) Multiple Coils 
16: Preset (Write) Multiple Holding Registers


Hardware Specifications



Power Supply

10 to 28.8 VDC (Two 24V power supplies needed if using a Series A L16/L18 controller)

Pointbus Current

75mA @ 5 VDC

Serial Line Voltages

RS-232: -15 to +15 VDC

RS-422/485: -7 to +12 VDC

Number of Inputs

1 Full duplex

Module Location

1734-TB or -TBS wiring base assembly (not included)

1734-TOP or -TOPS

LED Indicators

1 green/red module status indicator

1 green/red network status indicator

2 green TXD, RXD status indicators

Operating Temperature

32°F to +131°F (0°C to +55°C)

Storage Temperature

32°F to +131°F (0°C to +55°C)

Relative Humidity

5% to 95% RH with no condensation

Dimensions (H x W x D)

2.21 x 0.47 x 2.97 in

56 x 12 x 75.5 mm


30g peak acceleration (Operational)

50g peak acceleration (Non-operational)


Tested 5g @ 10 to 500 Hz

ESD immunity

6kV contact discharges

8kV air discharges


CB Safety 328.27 kB Last Modified 08/07/2014
Declaration of Conformity (RoHS/CE) 351.95 kB Last Modified 12/18/2020
ATEX Letter of Conformity 106.12 kB Last Modified 05/12/2022
UL/cUL; Class 1, Div. 2 234.92 kB Last Modified 04/08/2019
Country Approval - Eurasian Customs Union Conformity (EAC) (Wired) 1.92 MB Last Modified 02/11/2022
Declaration of REACH Compliance 339.85 kB Last Modified 02/08/2021