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Product short description:
  • 4 analog output channels
  • 0 to 20mA or 0 to 10V DC output range
  • 4 discrete output channels, open drain MOSFETS (1A DC loads, 0 to 35V DC)
  • 10 to 36V DC, 24V AC power
  • Modbus RTU high-speed RS-485

These modules drive four analog output channels and also feature four discrete outputs for on/off control. Isolation separates the output, power, and network circuits. Network communication adheres to the industry-standard RS-485 Modbus RTU protocol.

 

 

 

 

 

917MB, 918MB: DC Current/Voltage Modbus-RTU Output Modules with Discrete Outputs Description

These modules drive four analog output channels and also feature four discrete outputs for on/off control. Isolation separates the output, power, and network circuits.

Network communication adheres to the industry-standard RS-485 Modbus RTU protocol. AC and DC power sources are supported with non-polarized, diode-coupled terminals.

The analog outputs generate a signal based on communication from the host. They accommodate wide DC voltage or current ranges.

Discrete outputs provide simple on/off switching capability for external devices.

Combining analog outputs, on/off controllers, 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 make it reliable for both control room and distributed field I/O use in a broad range of temperature control applications.

Custom module configurations are also possible (consult factory for details).

DC Current or DC Voltage Outputs
Discrete Outputs

Models
917MB: 4 current output channels.
918MB: 4 voltage output channels.

Analog Output
917MB: 0 to 20mA, 4 to 20mA, 0 to 1mA DC.
918MB: 0 to 10V, 0 to 5V, 0 to 1V DC.

Discrete Output
Four output channels: Open-drain MOSFETs (1A DC loads) 0 to 35V DC.

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

Power Requirement: 12 to 36V DC (917MB), 10 to 36V DC (918MB), 24V AC.

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

Performance Specifications

General Analog Output

Resolution: See current/voltage output specifications for more information.

Ambient Temperature Effect: Better than ±0.001% of output span per °C, or ±1.0uV/°C, whichever is greater.

Ambient Temperature
Operation (917MB): -25°C to 60°C* (-13°F to 140°F*).
Operation (918MB): -25°C to 70°C (-13°F to 158°F).
Storage: -40°C to +85°C (-40°F to +185°F).
* Limit 917MB maximum ambient to 50°C (122°F) when using supply voltages less than 15V DC.

Current Output (917MB)

DC Current Output Ranges: Range user-configured. Range selected applies to all channels.
Output Range     Resolution      Accuracy (% span)
0 to 1mA                0.554% ±2.0%           (±0.002mA)
0 to 20mA             0.028% ±0.1%            (±0.02mA)
4 to 20mA             0.035% ±0.1%            (±0.02mA)

Maximum Output Current: 22.5mA DC typical.

Integral Non-Linearity: ±0.1% of span or ±2 LSB typical, whichever is larger, for spans equal to or greater than 16mA.

Output Compliance: 12V minimum, 12.7V typical.

Output Load Resistance Range: 0 to 630 ohms typical.

Response Time: 11ms typical into 500 ohms, for measurement to reach 98% of the final value in response to a step command. Actual response time will vary with load.

Voltage Output (918MB)

DC Voltage Output Ranges: Range user-configured. Selection applies to all channels.
Output Range      Resolution      Accuracy (% span)
0 to 1V                     0.274% ±0.6%             (±6mV)
0 to 5V                    0.055% ±0.1%              (±5mV)
0 to 10V                  0.027% ±0.1%             (±10mV)

Maximum Output Voltage: 11.255V DC typical.

Integral Non-Linearity: ±0.1% of span or ±2 LSB typical, whichever is larger, for spans equal to or greater than 5V.

Output Current: 0 to 10mA DC maximum.

Output Impedance: 1 ohm.

Output Short Circuit Protection: Included.

Response Time: 110μs rise time typical, 150μs fall time typical, unloaded, for output to reach 98% of the final value in response to a step command. Time varies with load.

Discrete Output

Output Type: Four independent open drain MOSFET switches with a common return that operate as low-side switches.

Output Voltage Range
0 to 35V DC (up to 1A/channel continuous).
External voltage source required.

Output ON Resistance: 0.15 ohms maximum.

Operation: Digital outputs are set to their OFF state following a software or power-on reset. Outputs may be set to user-defined states following a watchdog timeout. Watchdog timeout output control takes precedence over limit alarm control. Alarm control takes precedence over host control.

Output Response Time: 4.1ms typical, from receipt of command to gate transition of the output MOSFET.

Communication

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

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

Power and Isolation

Power Requirements
10 to 36V DC (918MB), 12 to 36V DC (917MB), 22 to 26V AC.

Supply Current
Supply    Current Draw (917)           Current Draw (918)
10V DC       Not Recommended              100mA maximum
12V DC        275mA maximum                   85mA maximum
24V DC        120mA maximum                   45mA maximum
24V AC         210mA rms maximum         85mA rms maximum

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

  • Standard Modbus RTU protocol with high-speed RS-485 communication (up to 115K bps)
  • 12-bit D/A yields 0.1% of span resolution and accuracy
  • Four outputs in a single inch-wide module reduces system costs and saves panel space
  • Four discrete outputs enable host-controlled on/off switching
  • Heavy-duty 1A solid-state relays provide dependable on/off control of industrial devices
  • Self-calibration lowers maintenance costs by reducing periodic manual calibration checks
  • Watchdog timers provide a configurable failsafe output state for use when host I/O communication is lost
  • Three-way isolation eliminates potential ground loops between power, output 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 60°C (-13°F to 140°F), limit 917MB ambient to 50°C maximum for supply voltages less than 15V

 

 

 

 

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

917MB, 918MB 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 13 × 12 × 3 in
Part Number

917MB-0900: DC Current Output Module, 918MB-0900: DC Voltage Output Module

Configuration

Windows Software Configuration

Communication

Modbus-RTU, RS422/485

Product Series

BusWorks 900MB

  • Description

    917MB, 918MB: DC Current/Voltage Modbus-RTU Output Modules with Discrete Outputs Description

    These modules drive four analog output channels and also feature four discrete outputs for on/off control. Isolation separates the output, power, and network circuits.

    Network communication adheres to the industry-standard RS-485 Modbus RTU protocol. AC and DC power sources are supported with non-polarized, diode-coupled terminals.

    The analog outputs generate a signal based on communication from the host. They accommodate wide DC voltage or current ranges.

    Discrete outputs provide simple on/off switching capability for external devices.

    Combining analog outputs, on/off controllers, 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 make it reliable for both control room and distributed field I/O use in a broad range of temperature control applications.

    Custom module configurations are also possible (consult factory for details).

    DC Current or DC Voltage Outputs
    Discrete Outputs

    Models
    917MB: 4 current output channels.
    918MB: 4 voltage output channels.

    Analog Output
    917MB: 0 to 20mA, 4 to 20mA, 0 to 1mA DC.
    918MB: 0 to 10V, 0 to 5V, 0 to 1V DC.

    Discrete Output
    Four output channels: Open-drain MOSFETs (1A DC loads) 0 to 35V DC.

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

    Power Requirement: 12 to 36V DC (917MB), 10 to 36V DC (918MB), 24V AC.

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

    Performance Specifications

    General Analog Output

    Resolution: See current/voltage output specifications for more information.

    Ambient Temperature Effect: Better than ±0.001% of output span per °C, or ±1.0uV/°C, whichever is greater.

    Ambient Temperature
    Operation (917MB): -25°C to 60°C* (-13°F to 140°F*).
    Operation (918MB): -25°C to 70°C (-13°F to 158°F).
    Storage: -40°C to +85°C (-40°F to +185°F).
    * Limit 917MB maximum ambient to 50°C (122°F) when using supply voltages less than 15V DC.

    Current Output (917MB)

    DC Current Output Ranges: Range user-configured. Range selected applies to all channels.
    Output Range     Resolution      Accuracy (% span)
    0 to 1mA                0.554% ±2.0%           (±0.002mA)
    0 to 20mA             0.028% ±0.1%            (±0.02mA)
    4 to 20mA             0.035% ±0.1%            (±0.02mA)

    Maximum Output Current: 22.5mA DC typical.

    Integral Non-Linearity: ±0.1% of span or ±2 LSB typical, whichever is larger, for spans equal to or greater than 16mA.

    Output Compliance: 12V minimum, 12.7V typical.

    Output Load Resistance Range: 0 to 630 ohms typical.

    Response Time: 11ms typical into 500 ohms, for measurement to reach 98% of the final value in response to a step command. Actual response time will vary with load.

    Voltage Output (918MB)

    DC Voltage Output Ranges: Range user-configured. Selection applies to all channels.
    Output Range      Resolution      Accuracy (% span)
    0 to 1V                     0.274% ±0.6%             (±6mV)
    0 to 5V                    0.055% ±0.1%              (±5mV)
    0 to 10V                  0.027% ±0.1%             (±10mV)

    Maximum Output Voltage: 11.255V DC typical.

    Integral Non-Linearity: ±0.1% of span or ±2 LSB typical, whichever is larger, for spans equal to or greater than 5V.

    Output Current: 0 to 10mA DC maximum.

    Output Impedance: 1 ohm.

    Output Short Circuit Protection: Included.

    Response Time: 110μs rise time typical, 150μs fall time typical, unloaded, for output to reach 98% of the final value in response to a step command. Time varies with load.

    Discrete Output

    Output Type: Four independent open drain MOSFET switches with a common return that operate as low-side switches.

    Output Voltage Range
    0 to 35V DC (up to 1A/channel continuous).
    External voltage source required.

    Output ON Resistance: 0.15 ohms maximum.

    Operation: Digital outputs are set to their OFF state following a software or power-on reset. Outputs may be set to user-defined states following a watchdog timeout. Watchdog timeout output control takes precedence over limit alarm control. Alarm control takes precedence over host control.

    Output Response Time: 4.1ms typical, from receipt of command to gate transition of the output MOSFET.

    Communication

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

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

    Power and Isolation

    Power Requirements
    10 to 36V DC (918MB), 12 to 36V DC (917MB), 22 to 26V AC.

    Supply Current
    Supply    Current Draw (917)           Current Draw (918)
    10V DC       Not Recommended              100mA maximum
    12V DC        275mA maximum                   85mA maximum
    24V DC        120mA maximum                   45mA maximum
    24V AC         210mA rms maximum         85mA rms maximum

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

  • Features & Benefits

    • Standard Modbus RTU protocol with high-speed RS-485 communication (up to 115K bps)
    • 12-bit D/A yields 0.1% of span resolution and accuracy
    • Four outputs in a single inch-wide module reduces system costs and saves panel space
    • Four discrete outputs enable host-controlled on/off switching
    • Heavy-duty 1A solid-state relays provide dependable on/off control of industrial devices
    • Self-calibration lowers maintenance costs by reducing periodic manual calibration checks
    • Watchdog timers provide a configurable failsafe output state for use when host I/O communication is lost
    • Three-way isolation eliminates potential ground loops between power, output 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 60°C (-13°F to 140°F), limit 917MB ambient to 50°C maximum for supply voltages less than 15V

     

     

     

     

  • 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

    917MB, 918MB 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 13 × 12 × 3 in
    Part Number

    917MB-0900: DC Current Output Module, 918MB-0900: DC Voltage Output Module

    Configuration

    Windows Software Configuration

    Communication

    Modbus-RTU, RS422/485

    Product Series

    BusWorks 900MB