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Product short description:
  • 4 input channels, thermocouple (types J, K, T, R, S, E, B, N) or millivolt (±100mV DC) input
  • 4 alarm channels, open drain MOSFETS (1A DC loads, 0 to 35V DC)
  • 10 to 36V DC, 24V AC power
  • Modbus-RTU high-speed RS-485

This signal conditioner is a four-channel analog input module with four discrete outputs. It filters and linearizes thermocouple inputs while providing isolation between input, output, power, and network circuits. Cold junction compensation and upscale/downscale sensor break detection are standard.

 

 

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924MB: Thermocouple/milliVolt Modbus-RTU Input Module with Limit Alarms Description

This signal conditioner is a four-channel analog input module with four discrete outputs. It filters and linearizes thermocouple inputs while providing isolation between input, output, power, and network circuits. Cold junction compensation and upscale/downscale sensor break detection are standard. AC and DC power sources are supported with non-polarized, diode-coupled terminals.

The programmable inputs accommodate eight thermocouple types plus wide-range millivolt signals. Flexible discrete outputs operate as alarms or on/off controllers. As limit alarms, each discrete output can be configured with high and/or low set-points exclusively tied to an analog input channel. Alarm trips function without host communication enabling low-cost stand-alone alarms as well as local backup for the primary control system. Otherwise, on/off control is based on commands issued by the host system.

Combining flexible transmitter functions, mixed signal I/O, alarm support, 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).

Thermocouple or Millivolt Input
Limit Alarms or Discrete Outputs

Model: 924MB: 4 input channels
Input:
Four input channels:
Thermocouple (types J, K, T, R, S, E, B, N)
±100mV DC
Output:
Four output channels:
Open-drain MOSFETs (1A DC loads)
0 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

General Output

Resolution:
±100mV DC input: 0.1%
Thermocouple input: 0.1°C (0.18°F)
Ambient Temperature Effect: Better than ±0.005% of input span per °C, or ±1.0uV/°C, whichever is greater.
Noise Rejection:
Normal mode: 40dB @ 60Hz, typical
Common mode: 140dB @ 60Hz, typical
Input Filter Bandwidth: -3dB at 3Hz, typical
Input Conversion Rate: 90ms per channel

Thermocouple Input

Thermocouple Input Ranges: Thermocouple type user-configured. Type selected applies to all channels. Signal linearization, cold-junction compensation, and open circuit or lead break
detection are included.

TC                  °C Range (°F Range)                        Accuracy
J            -210 to  760°C   (-346 to 1400°F)                ±0.5°C
K            -200 to 1372°C (-328 to 2502°F)                ±0.5°C
T            -260 to  400°C  (-436 to 752°F)                   ±0.5°C
R             -50 to 1768°C (-58 to 3214°F)                    ±1.0°C
S             -50 to 1768°C (-58 to 3214°F)                    ±1.0°C
E           -200 to 1000°C (-328 to 1832°F)                   0.5°C
B            260 to 1820°C (500 to 3308°F)                  ±1.0°C
N          -230 to 1300°C (-382 to 2372°F)                 ±1.0°C
Note 1: Accuracy is given with CJC switched off.
Relative inaccuracy with CJC enabled may increase by ±0.5°C.

Thermocouple Break Detection: TC sensor failure can be configured for either upscale or downscale. Selection applies to all channels.

DC milliVolt Input

milliVolt Input Ranges: ±100mV DC
milliVolt Input Accuracy: ±0.1% of input range

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, 1A DC maximum for each output.
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 can optionally 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
  • Read Holding Registers
  • Read Input Registers
  • Force Single Coil
  • Preset Single Register
  • Force Multiple Coils
  • Preset Multiple Registers
  • Report Slave ID
  • Reset Slave

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

Power and Isolation

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

Supply Current:
Supply           Current Draw
10V DC     100mA maximum
24V DC       45mA maximum
24V AC       85mA rms maximum

Isolation
1500V AC for 60 seconds or 250V AC continuous.
4-way isolation between input, network, power and discrete I/O circuits. Inputs are isolated channel-to channel for common mode voltage to ±5V DC.

 

 

  • Standard Modbus-RTU protocol with high-speed RS-485 communication (up to 115K bps)
  • 16-bit sigma-delta A/D yields 0.1°C resolution and 0.5°C measurement accuracy
  • Thermocouple linearization and sensor break detection ensure reliable measurements
  • Four discrete outputs enable local temperature limit alarms or 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 fail-safe output state for use when host I/O communication is lost
  • Four-way isolation eliminates potential ground loops between power, input, 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 70°C (-13°F to 158°F).

 

 

Modbus/RS485 an Introduction White Paper (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.
How to Configure Kepware KEPServerEX 5.0 for Communications with Acromag BusWorks Modbus I/O Modules Application Note
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 2009 to Communicate with Acromag BusWorks and EtherStax Modbus I/O Modules Via an OPC Server Application Note
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 Modbus I/O Modules, outlines configuration of a KEPServerEX OPC server. This document focuses on setting up controls and...

Manuals

924MB 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)

BusWorks 900MB Modbus RTU Configuration Software (Log in to download the file)
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Additional information

Weight 16 oz
Dimensions 13 × 12 × 3 in
Configuration

Windows Software Configuration

Part Number

924MB-0900: 4 input channels

Communication

Modbus-RTU, RS422/485

Product Series

BusWorks 900MB

  • Description

    924MB: Thermocouple/milliVolt Modbus-RTU Input Module with Limit Alarms Description

    This signal conditioner is a four-channel analog input module with four discrete outputs. It filters and linearizes thermocouple inputs while providing isolation between input, output, power, and network circuits. Cold junction compensation and upscale/downscale sensor break detection are standard. AC and DC power sources are supported with non-polarized, diode-coupled terminals.

    The programmable inputs accommodate eight thermocouple types plus wide-range millivolt signals. Flexible discrete outputs operate as alarms or on/off controllers. As limit alarms, each discrete output can be configured with high and/or low set-points exclusively tied to an analog input channel. Alarm trips function without host communication enabling low-cost stand-alone alarms as well as local backup for the primary control system. Otherwise, on/off control is based on commands issued by the host system.

    Combining flexible transmitter functions, mixed signal I/O, alarm support, 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).

    Thermocouple or Millivolt Input
    Limit Alarms or Discrete Outputs

    Model: 924MB: 4 input channels
    Input:
    Four input channels:
    Thermocouple (types J, K, T, R, S, E, B, N)
    ±100mV DC
    Output:
    Four output channels:
    Open-drain MOSFETs (1A DC loads)
    0 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

    General Output

    Resolution:
    ±100mV DC input: 0.1%
    Thermocouple input: 0.1°C (0.18°F)
    Ambient Temperature Effect: Better than ±0.005% of input span per °C, or ±1.0uV/°C, whichever is greater.
    Noise Rejection:
    Normal mode: 40dB @ 60Hz, typical
    Common mode: 140dB @ 60Hz, typical
    Input Filter Bandwidth: -3dB at 3Hz, typical
    Input Conversion Rate: 90ms per channel

    Thermocouple Input

    Thermocouple Input Ranges: Thermocouple type user-configured. Type selected applies to all channels. Signal linearization, cold-junction compensation, and open circuit or lead break
    detection are included.

    TC                  °C Range (°F Range)                        Accuracy
    J            -210 to  760°C   (-346 to 1400°F)                ±0.5°C
    K            -200 to 1372°C (-328 to 2502°F)                ±0.5°C
    T            -260 to  400°C  (-436 to 752°F)                   ±0.5°C
    R             -50 to 1768°C (-58 to 3214°F)                    ±1.0°C
    S             -50 to 1768°C (-58 to 3214°F)                    ±1.0°C
    E           -200 to 1000°C (-328 to 1832°F)                   0.5°C
    B            260 to 1820°C (500 to 3308°F)                  ±1.0°C
    N          -230 to 1300°C (-382 to 2372°F)                 ±1.0°C
    Note 1: Accuracy is given with CJC switched off.
    Relative inaccuracy with CJC enabled may increase by ±0.5°C.

    Thermocouple Break Detection: TC sensor failure can be configured for either upscale or downscale. Selection applies to all channels.

    DC milliVolt Input

    milliVolt Input Ranges: ±100mV DC
    milliVolt Input Accuracy: ±0.1% of input range

    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, 1A DC maximum for each output.
    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 can optionally 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
    • Read Holding Registers
    • Read Input Registers
    • Force Single Coil
    • Preset Single Register
    • Force Multiple Coils
    • Preset Multiple Registers
    • Report Slave ID
    • Reset Slave

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

    Power and Isolation

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

    Supply Current:
    Supply           Current Draw
    10V DC     100mA maximum
    24V DC       45mA maximum
    24V AC       85mA rms maximum

    Isolation
    1500V AC for 60 seconds or 250V AC continuous.
    4-way isolation between input, network, power and discrete I/O circuits. Inputs are isolated channel-to channel for common mode voltage to ±5V DC.

     

     

  • Features & Benefits

    • Standard Modbus-RTU protocol with high-speed RS-485 communication (up to 115K bps)
    • 16-bit sigma-delta A/D yields 0.1°C resolution and 0.5°C measurement accuracy
    • Thermocouple linearization and sensor break detection ensure reliable measurements
    • Four discrete outputs enable local temperature limit alarms or 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 fail-safe output state for use when host I/O communication is lost
    • Four-way isolation eliminates potential ground loops between power, input, 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 70°C (-13°F to 158°F).

     

     

  • Tech Papers

    Modbus/RS485 an Introduction White Paper (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.
    How to Configure Kepware KEPServerEX 5.0 for Communications with Acromag BusWorks Modbus I/O Modules Application Note
    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 2009 to Communicate with Acromag BusWorks and EtherStax Modbus I/O Modules Via an OPC Server Application Note
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  • Specs & Data Sheets

    Manuals

    924MB 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

    BusWorks 900MB Modbus RTU Configuration Software (Log in to download the file)
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      • Lightweight and compact size
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      • Barrier strip or spring clamp terminal block kits
      • Provide safe and secure wiring connections
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      Select options
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  • Additional information

    Additional information

    Weight 16 oz
    Dimensions 13 × 12 × 3 in
    Configuration

    Windows Software Configuration

    Part Number

    924MB-0900: 4 input channels

    Communication

    Modbus-RTU, RS422/485

    Product Series

    BusWorks 900MB