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Product short description:
  • Active-High Inputs, Sourcing Outputs (High-Side Switching)
  • 12 input and/or 12 output channels
  • 0 to 35V DC I/O range
  • 10 to 36V DC, 24V AC power
  • Modbus-RTU high-speed RS-485

These modules provide twelve discrete input and/or output channels. Isolation separates the I/O, power, and network circuits. Network communication adheres to the industry-standard RS-485 Modbus RTU protocol.

904MB, 905MB, 906MB: Multi-Channel Discrete I/O Modules Description

These modules provide twelve discrete input and/or output channels. Isolation separates the I/O, power, and network circuits. Network communication adheres to the industry-standard RS-485 Modbus RTU protocol. Both AC and DC power sources are supported with wide range, non-polarized, diode-coupled terminals.

The outputs are intended for current-sourcing or high-side switching applications. The buffered inputs are active-high. These models are the complement of the 901, 902, and 903 units which have low-side output switches and active-low inputs. Socketed pull-down resistors are easily removed or exchanged to satisfy your application requirements.

The 906MB model has twelve input/output points that may be used as inputs or outputs on a bit-by-bit basis. Outputs may be read back to verify output settings.

Combining flexible I/O types, wide I/O ranges, and a network interface in a single package, makes this instrument extremely powerful. Multi-channel design adds cost-efficiency and allows high-density mounting. Plus, safe, rugged construction makes these modules reliable for use in both control room and distributed field I/O applications. Custom module configurations are also possible (consult factory for details).

Active-High Inputs Sourcing Outputs (High-Side Switching)

Models
904MB: 12 input channels.
905MB: 12 output channels.
906MB: 12 input/output channels.

Input
Twelve input channels (904, 906 models only).
0 to 35V DC.

Output
Twelve output channels (905, 906 models only).
6 to 35V DC.

Network Communication: Modbus-RTU high-speed RS-485.

Power Requirement: 10 to 36V DC, 24V AC.

Approvals
CE marked. UL, cUL listed.
Class I; Division 2; Groups A, B, C, D.

Performance Specifications

Discrete Inputs (904 & 906 models only)

Input Type: 12 active-high, buffered inputs, with a common connection. Inputs include transient suppression devices and series connected 100K ohm resistors, plus diode over-voltage clamps to the internal +5V supply.

Input Signal Voltage Range: 0 to 35V DC, maximum.

Input Current: 293μA, typical at 35V DC.

Input Signal Threshold
TTL compatible with 100mV of hysteresis, typical.
Thus, Low-to-High threshold is 1.5V DC.
High-to-Low is 1.4VDC, typical.
Limited to TTL levels of 0.8VDC (max. LOW level) and 2.0VDC (min. HIGH level).

Input Resistance
5.6K ohms with standard factory pull-down resistors installed.
100K ohms without pull-downs.

Input Hysteresis: 100mV DC, typical.

Input Response Time
500ns for low-to-high, 2μS for high-to-low, typical.
Micro controller samples inputs as a group every 10mS.

Discrete Outputs (905 & 906 models only)

Output Type: 12 independent, open-source, MOSFET switches that operate as high-side switches.

Output Voltage Range
6 to 35V DC (0 to 250mA/channel continuous).
External excitation voltage required.

Output ON Resistance: 0.15 ohms maximum.

Output Response Time
Outputs update within 50ms of a write command and switch within 5mS of receipt of command.
Loopback response (906MB) is 1μS low-to high, 5μS high-to-low.

General

I/O Pull-downs and Socket: 5.6K ohm pull-down resistor SIPs are installed in sockets at each port (four-channels per port).

Excitation (per port): External excitation voltage for each four-channel port is limited to 35V or less.

Supported Modbus Commands: The command/response protocol for communicating with this module adheres to the Modbus/RTU standard for the following Modbus functions:

  • Read Coil (Output) Status
  • Read Input Status
  • Read Holding Registers
  • Read Input Registers
  • Force Single Coil (Output)
  • Preset Single Register
  • Reset Slave
  • Force Multiple Coils (Outputs)
  • Preset Multiple Registers
  • Report Slave ID

LED Indicators: LEDs indicate power, status, and discrete level.

Power Requirements
10 to 36V DC.
22 to 26V AC.

Supply Current
Supply         Current Draw.
10V DC     90mA maximum.
24V DC     40mA maximum.
24V AC      75mA rms maximum.

Isolation
1500V AC for 60 seconds or 250V AC continuous.
3-way isolation between I/O, network, and power circuits.

  • Standard Modbus RTU protocol with high-speed RS-485 communication (up to 115K bps)
  • Twelve I/O channels in a single inch-wide unit reduces system costs and saves panel space
  • High-voltage, high-current, open-source outputs enable direct (high-side) control of external devices
  • High-voltage buffered inputs monitor discrete levels from a variety of industrial devices
  • Tandem input/output circuitry (906 models only) connects input buffers with open-source outputs for convenient loopback monitoring of the output state
  • Watchdog timers provide a configurable fail-safe output state for use when host I/O communication is lost
  • Three-way isolation eliminates potential ground loops between power, I/O, and network circuitry
  • Self-diagnostics monitor microcontroller activity to detect operational failures (lock-up) and execute a reset to restore communication
  • Operating temperature: -25°C to 70°C (-13°F to 158°F)

 

What is Modbus/RS485? An Introduction - 8500648 (Log in to view the file)
Modbus/RS485 Network an Introduction White Paper This white paper describes the operation of Modbus as it relates to Acromag Series 900MB I/O modules.   Learn more: What is Ethernet/IP?
How to Configure Kepware KEPServerEX 5.0 for Communications with Modbus I/O Modules - 8500880
Configuring Kepware KEPServerEX 5.0 for Communications with Acromag BusWorks Modbus I/O Modules Introduction This document provides example steps for configuring the Kepware KEPServerEX OPC Server for communications with Acromag Busworks Modbus RTU and Modbus TCP/IP Distributed I/O Modules. Once the server is configured, data may be read from or written to the I/O module using...
How to Configure LabVIEW to Communicate with Modbus I/O Modules Via an OPC Server - 8500881
Configuring LabVIEW 2009 to Communicate with Acromag BusWorks and EtherStax Modbus I/O Modules via an OPC Server Introduction National Instruments™ LabVIEW can be used to monitor and control Acromag BusWorks ® and EtherStax ® Modbus I/O modules via an OPC server. A separate application note, Configuring Kepware KEPServerEX® 5.0 for communications with Acromag BusWorks and EtherStax...

Manuals

904MB, 905MB, 906MB User Manual (Log in to download the file)

How to Use SIIG USB-to-Serial Cable With Windows Tech Note (Log in to download the file)

900C-SIP: Modbus RTU Configuration Software Information Page (Log in to download the file)
  • Compare

    5034-202: RS-485 to 3-wire Cable Converter and Cable

    RS-485 to 3-wire cable converter and cable, DB-9M to 3 x 12AWG RS-485 cable, 8 ft.
    Select options
  • Compare

    5034-214: RS232 to RS485 Serial Port Converter

    Non-isolated RS232-to-RS485 serial port converter, RS232 port-powered, DB-9F to DB-9F.
    Select options
  • Compare

    900C-SIP: Configuration Software Interface Package

    • Configuration Software
    • USB-to-RS232 Adapter
    • RS232-to-RS485 Adapter
    • Interface Cable
     
    Select options

Additional information

Weight 16 oz
Dimensions 1.5 × 5 × 4.5 in
Part Number

904MB-0900: 12 input channels, 905MB-0900: 12 output channels, 906MB-0900: 12 input/output channels

Configuration

Windows Software Configuration

Communication

Modbus-RTU, RS422/485

Product Series

BusWorks 900MB

  • Description

    904MB, 905MB, 906MB: Multi-Channel Discrete I/O Modules Description

    These modules provide twelve discrete input and/or output channels. Isolation separates the I/O, power, and network circuits. Network communication adheres to the industry-standard RS-485 Modbus RTU protocol. Both AC and DC power sources are supported with wide range, non-polarized, diode-coupled terminals.

    The outputs are intended for current-sourcing or high-side switching applications. The buffered inputs are active-high. These models are the complement of the 901, 902, and 903 units which have low-side output switches and active-low inputs. Socketed pull-down resistors are easily removed or exchanged to satisfy your application requirements.

    The 906MB model has twelve input/output points that may be used as inputs or outputs on a bit-by-bit basis. Outputs may be read back to verify output settings.

    Combining flexible I/O types, wide I/O ranges, and a network interface in a single package, makes this instrument extremely powerful. Multi-channel design adds cost-efficiency and allows high-density mounting. Plus, safe, rugged construction makes these modules reliable for use in both control room and distributed field I/O applications. Custom module configurations are also possible (consult factory for details).

    Active-High Inputs Sourcing Outputs (High-Side Switching)

    Models
    904MB: 12 input channels.
    905MB: 12 output channels.
    906MB: 12 input/output channels.

    Input
    Twelve input channels (904, 906 models only).
    0 to 35V DC.

    Output
    Twelve output channels (905, 906 models only).
    6 to 35V DC.

    Network Communication: Modbus-RTU high-speed RS-485.

    Power Requirement: 10 to 36V DC, 24V AC.

    Approvals
    CE marked. UL, cUL listed.
    Class I; Division 2; Groups A, B, C, D.

    Performance Specifications

    Discrete Inputs (904 & 906 models only)

    Input Type: 12 active-high, buffered inputs, with a common connection. Inputs include transient suppression devices and series connected 100K ohm resistors, plus diode over-voltage clamps to the internal +5V supply.

    Input Signal Voltage Range: 0 to 35V DC, maximum.

    Input Current: 293μA, typical at 35V DC.

    Input Signal Threshold
    TTL compatible with 100mV of hysteresis, typical.
    Thus, Low-to-High threshold is 1.5V DC.
    High-to-Low is 1.4VDC, typical.
    Limited to TTL levels of 0.8VDC (max. LOW level) and 2.0VDC (min. HIGH level).

    Input Resistance
    5.6K ohms with standard factory pull-down resistors installed.
    100K ohms without pull-downs.

    Input Hysteresis: 100mV DC, typical.

    Input Response Time
    500ns for low-to-high, 2μS for high-to-low, typical.
    Micro controller samples inputs as a group every 10mS.

    Discrete Outputs (905 & 906 models only)

    Output Type: 12 independent, open-source, MOSFET switches that operate as high-side switches.

    Output Voltage Range
    6 to 35V DC (0 to 250mA/channel continuous).
    External excitation voltage required.

    Output ON Resistance: 0.15 ohms maximum.

    Output Response Time
    Outputs update within 50ms of a write command and switch within 5mS of receipt of command.
    Loopback response (906MB) is 1μS low-to high, 5μS high-to-low.

    General

    I/O Pull-downs and Socket: 5.6K ohm pull-down resistor SIPs are installed in sockets at each port (four-channels per port).

    Excitation (per port): External excitation voltage for each four-channel port is limited to 35V or less.

    Supported Modbus Commands: The command/response protocol for communicating with this module adheres to the Modbus/RTU standard for the following Modbus functions:

    • Read Coil (Output) Status
    • Read Input Status
    • Read Holding Registers
    • Read Input Registers
    • Force Single Coil (Output)
    • Preset Single Register
    • Reset Slave
    • Force Multiple Coils (Outputs)
    • Preset Multiple Registers
    • Report Slave ID

    LED Indicators: LEDs indicate power, status, and discrete level.

    Power Requirements
    10 to 36V DC.
    22 to 26V AC.

    Supply Current
    Supply         Current Draw.
    10V DC     90mA maximum.
    24V DC     40mA maximum.
    24V AC      75mA rms maximum.

    Isolation
    1500V AC for 60 seconds or 250V AC continuous.
    3-way isolation between I/O, network, and power circuits.

  • Features & Benefits

    • Standard Modbus RTU protocol with high-speed RS-485 communication (up to 115K bps)
    • Twelve I/O channels in a single inch-wide unit reduces system costs and saves panel space
    • High-voltage, high-current, open-source outputs enable direct (high-side) control of external devices
    • High-voltage buffered inputs monitor discrete levels from a variety of industrial devices
    • Tandem input/output circuitry (906 models only) connects input buffers with open-source outputs for convenient loopback monitoring of the output state
    • Watchdog timers provide a configurable fail-safe output state for use when host I/O communication is lost
    • Three-way isolation eliminates potential ground loops between power, I/O, and network circuitry
    • Self-diagnostics monitor microcontroller activity to detect operational failures (lock-up) and execute a reset to restore communication
    • Operating temperature: -25°C to 70°C (-13°F to 158°F)

     

  • Tech Papers

    What is Modbus/RS485? An Introduction - 8500648 (Log in to view the file)
    Modbus/RS485 Network an Introduction White Paper This white paper describes the operation of Modbus as it relates to Acromag Series 900MB I/O modules.   Learn more: What is Ethernet/IP?
    How to Configure Kepware KEPServerEX 5.0 for Communications with Modbus I/O Modules - 8500880
    Configuring Kepware KEPServerEX 5.0 for Communications with Acromag BusWorks Modbus I/O Modules Introduction This document provides example steps for configuring the Kepware KEPServerEX OPC Server for communications with Acromag Busworks Modbus RTU and Modbus TCP/IP Distributed I/O Modules. Once the server is configured, data may be read from or written to the I/O module using...
    How to Configure LabVIEW to Communicate with Modbus I/O Modules Via an OPC Server - 8500881
    Configuring LabVIEW 2009 to Communicate with Acromag BusWorks and EtherStax Modbus I/O Modules via an OPC Server Introduction National Instruments™ LabVIEW can be used to monitor and control Acromag BusWorks ® and EtherStax ® Modbus I/O modules via an OPC server. A separate application note, Configuring Kepware KEPServerEX® 5.0 for communications with Acromag BusWorks and EtherStax...
  • Specs & Data Sheets

    Manuals

    904MB, 905MB, 906MB User Manual (Log in to download the file)

    How to Use SIIG USB-to-Serial Cable With Windows Tech Note (Log in to download the file)

  • Software

    900C-SIP: Modbus RTU Configuration Software Information Page (Log in to download the file)
  • Accessories

    • Compare

      5034-202: RS-485 to 3-wire Cable Converter and Cable

      RS-485 to 3-wire cable converter and cable, DB-9M to 3 x 12AWG RS-485 cable, 8 ft.
      Select options
    • Compare

      5034-214: RS232 to RS485 Serial Port Converter

      Non-isolated RS232-to-RS485 serial port converter, RS232 port-powered, DB-9F to DB-9F.
      Select options
    • Compare

      900C-SIP: Configuration Software Interface Package

      • Configuration Software
      • USB-to-RS232 Adapter
      • RS232-to-RS485 Adapter
      • Interface Cable
       
      Select options
  • Additional information

    Additional information

    Weight 16 oz
    Dimensions 1.5 × 5 × 4.5 in
    Part Number

    904MB-0900: 12 input channels, 905MB-0900: 12 output channels, 906MB-0900: 12 input/output channels

    Configuration

    Windows Software Configuration

    Communication

    Modbus-RTU, RS422/485

    Product Series

    BusWorks 900MB