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DIN Rail Mount Universal Communication Module


Niobrara's DUCM is a DIN rail mounted stand-alone version of our popular QUCM.
  • DIN rail mount
  • 24VDC Opeation
  • 100BaseT RJ45 Ethernet port
  • Optional second 100BaseT Ethernet with internal switch supporting daisy-chain or copper ring with RSTP
  • Two Isolated serial ports
  • - each selectable between RS-232 (RJ-45) and RS-485 (5-position screw terminal)
  • LCD Dispaly and keypad
  • - Easy setup from the front panel

Uses for the DUCM

Data Concentrator
  • Read data from external devices and/or the PLC.
  • Allow external devices to write data to the DUCM.
  • Both the PLC and external devices can read the gathered data.
  • Time-stamp data for later retrieval.
Protocol Converter
  • Allow devices with different protocols on separate ports to communicate.
  • Non-Modbus devices and read/write the DUCM.
Email Client
  • Send and receive e-mails for alarm conditions.
Web Server*
  • Access device data and configure setup parameters with a web page.
  • Allow Ethernet clients to access serial slaves.
  • Allow serial master to access Ethernet servers.


The engineers at Niobrara have written several applications
  • Interfacing an ACCU-SORT Scanner to a Quantum PLC.
  • Interfacing Modbus RTU master to 3694(R) devices.
  • Interfacing Modbus RTU master to an Allen Bradley® DF1 device.
  • Interfacing Modbus RTU master to ENRON/Daniel Modbus Slaves.
  • Gathering data from Simpson Hawk® meters for the Quantum PLC.

The source code for these applications is available here. The applications can be used as is or modified to solve your PLC communication problem or used as examples to start your own DUCM application development.

QUCM Language

The DUCM is programmed via Niobrara's QUCM language. The language has a BASIC-like structure which makes it easy to read and follow. Powerful language extensions for data communications and PLC interfacing make it ideal for use as a PLC communication language. A TCP/IP stack is built in, making it easy to write application layer protocols using TCP, UDP, PPP, and IP. The language is compiled for the fastest possible execution. The compiler is included at no extra charge.

Although the DUCM is designed for user programming, many companies choose to have Niobrara write their UCM code. Contact Niobrara for a quote.

Application Areas

The DUCM can run a single multi-threaded applications. All threads have access to the serial ports, the LCD display, keypad, the real-time clock, the TCP/IP stack, and the internal registers.

Serial Ports

The two serial ports on the DUCM are software selectable RS-232 or RS-485. They RJ45 ports are RS-232 while the removable 5-position terminals are RS-485. They are independently configurable as to baud rate, parity, data bits, and stop bits. Write the protocol of your equipment to:
  • Be a Master or a Slave device while multidropping up to 32 devices off of either port
  • Build a Protocol Converter
  • Build a Data Concentrator for serial or Ethernet devices
  • Build a gateway to allow ASCII devices onto the Ethernet network
  • Dial-out to your ISP and communicate on the Internet using PPP

Several serial protocols have been implemented in various products and are available online:

  • 3964R
  • Caterpillar EMCP Genset
  • Caterpillar 3500 Engines
  • DNP 3.0
  • Dupline I/O
  • Allen-Bradley DF1
  • Elliott Flow Computer
  • ENRON/Daniel Modbus
  • Cutler-Hammer INCOM
  • GE Multilin 169 Plus
  • Johnson Controls N2 (Metasys®)
  • Mitsubishi UPS
  • Siemens SEAbus & SEAbus+
  • Simpson Hawk meters

Ethernet Port

The single 100BaseT RJ45 Ethernet port defaults to Modbus/TCP protocol. The DUCM has a TCP/IP stack which the user's application can access for easy implementation of various application layer protocols. Several application layer protocols have been implemented; examples are available online.
  • Cutler-Hammer INCOM
  • Chat
  • FTP
  • DNS
  • SNMP (Client or server)
  • SMTP
  • Telnet
  • POP3

LCD / Keypad and Real-Time Clock

The DUCM has a front panel display and keypad under Application control.

A real-time clock is available to the applications and is especially useful for scheduling events or time-stamping data.

Ordering Information

The DUCM is available as:
     * DUCM+102     with 2 isolated RS-232/RS-485 ports, 1 Ethernet port (RJ45 100BaseT connector).
     * DUCM+202     with 2 isolated RS-232/RS-485 ports, 2 Ethernet ports (RJ45 100BaseT connector).

Related Equipment

The DUCM has the following equipment available:
     * MM1     RS-232 cable for connecting to a 9-pin PC serial port.
     * MU7     RS-422 cable for connecting to a 9-pin SY/MAX serial port.
     * TR121ST     120VAC (US) wall mount power supply.


Warranty / Manual: The DUCM is furnished with a user manual on cd and carries a one year warranty from the date of shipment. During the warranty period, free firmware upgrades are available. See Niobrara's Standard Terms and Conditions of Sale for additional warranty information.

Dimensions: DIN rail mount 4.4" wide by 4.4" tall by 3.5" deep. Approximately 1.2 pounds net.

Power Requirements: 9-30VDC 6W - 3 position removable connector is provided.


  • Module: LCD with backlight and two red LEDs for error
  • Serial Ports: Transmit and Receive for each port
  • Ethernet: Link/Activity, 10/100
  • Modbus Plus: Active, Channel A Error, Channel B Error

Ethernet Port: 10/100BaseT port with RJ45 connector on bottom of unit. Optional second Ethenet port with built-in switch.

Serial Ports: Two isolated ports selectable between RS-232 (RJ45 connector) and RS-485 (5 position removable screw terminal is provided). Independently configurable for baud rate, data bits, parity, stop bits, and protocol. RS-485 mode is 2- and 4-wire compatible. Optional factory installed serial ports with two RS-232 or two RS-485 ports.

Environmental:Operating conditions are 0-50C; humidity up to 90% noncondensing; pressure altitude -200 to +10,000 ft MSL.

Effective 11 May 2012 - Specifications subject to change without notice.