Design Features

The NTX-20 controller is an economical solution for feeder automation where Ethernet and/or serial connectivity is desired. Combining both Ethernet and serial connectivity, master gateway, IED gateway, router, internal GPS precision time reference interface, binary inputs, and power supply functions in a single–package module, the NTX-20 controller interfaces with distribution line switches, capacitor banks, transformers, distributed substation breaker bays, water pumps, valve control devices, etc., to provide low–cost automation with the highest reliability possible. 


Deployed on a per–device basis, the NTX-20 with optional control output modules adds control and data acquisition to a power distribution system for one or more feeder line switches, auto–regulator transformers, and capacitor banks.


Using this switch control and our optional D 060  Intelligent Analog Input Module, your distribution automation system can plot alternate distribution paths around faulty circuits to restore service automatically, using our fault detection, isolation and restoration (FDIR) application from a centralized master, or with the CentrixTM Advanced Feeder Automation platform (our substation island-based feeder platform). Trouble–spot displays at the control center to give operators precise location information aid in manually dispatching service personnel. The result is shorter service interruptions, affecting smaller areas. 


The NTX-20 provides a low cost data acquisition and control solution for both power distribution and water and gas applications. Local closed–loop control or calculations can be easily accomplished with the optional IEC 611131–compliant Programmable Logic Controller (PLC). The NTX-20 and all optional expansion modules are 35 mm DIN–rail compatible, for convenient mounting in cabinets or remote device enclosures.


Design Features:

  • High–performance 32–bit RISC processor with DSP extension
  • Linux® operating system
  • Extended temperature range: –10°to 70°C
  • Multiple Virtual RTUTM database mapping
  • Field programmable; remotely programmable via WAN/LAN
  • On–line configuration, monitoring, and diagnostic facilities 
  • 10/100 BaseT with DNP3 and Modbus RTU over TCP/IP or UDP 
  • Two isolated serial ports, configurable for RS–232 or RS–485 interfaces
  • SOE for up to 48 binary inputs
  • GPS time reference interface (optional external GPS clock/antenna)
  • Optional IEC 611131–compliant NTU Logic PLC that executes user–defined control and/or calculation algorithms
  • Two USB channels to support maintenance and firmware updates
  • Broad 18 to 36 VDC power input range
  • 35 mm DIN–rail compatible design
  • High reliability under the harshest environmental and electrical conditions 



  • Fault detection, using the optional D 060 
  • Feeder automation
  • SCADA for single/multiple circuit devices
  • Water, wastewater, gas and pipeline monitoring and control


Configuration Options:

  • Control relay outputs
  • Expanded binary with or without time or counter inputs
  • DC analog inputs 
  • DC analog outputs


The NTX-20 is a 35 mm DIN–rail mounted dual–PCB module.  It uses an ARM 9E 32–bit RISC processor. The peripheral set includes USB Full Speed Host and Device interfaces and a 10/100 Base T Ethernet MAC. The NTX-20 operating system is Linux with flash memory. The internal GPS Satellite Receiver synchronizes the system clock with UTC time. An optional external antenna is required to receive the NMEA-0183 protocol satellite time messages.


The internal power supply accepts a 18–36 VDC input, with a maximum consumption of 10 watts. The NTX-20 has a 4x6 optically isolated control relay driver matrix, with a capacity of 24 control relay output drivers. External control relay modules can be supplied as momentary or latching relays with a variety of contact ratings. Relay coils are for a standard nominal 24 VDC external power source.


An optional I/O expansion enables addition of the following modules:

  • Up to two 1–channel analog output modules (isolated 4–20 mA output) with added external power supply
  • Up to four 8–point binary input expansion modules (binary with or without time, Form A or two consecutive points for Form C counters)
  • Up to six 6–point DC analog input modules (0 ± 1 mA or 4–20 mA input)


The NTX-20 network interface supports a DNP/IP and Modbus RTU/IP client, a DNP/IP and Modbus RTU/IP server, or multiples of both. Two isolated serial channels are individually configurable for master slave (secondary) or IED master (primary) Modbus RTU and DNP3 Level 3 protocol emulations with configurable baud rates of 300 to 115.2 Kbps. 


Legacy primary (master) protocols, such as Cooper 2179, are supported. Legacy secondary (slave) protocols, such as ACS7000, L&G 8979, Harris 5000, SC1801, SComD, etc., are also supported (others may be added based on customer demand). 


The NTX-20 includes 16 optically isolated binary inputs that are configurable for binary with time (SOE), binary without time (simple status), Form A counter, or two consecutive points as a Form C counter. The binary inputs are scanned by a separate microprocessor at a 1–millisecond rate for a 1–millisecond event resolution. A sliding software de–bounce filter requires a changed contact to be in the same state for four consecutive millisecond scans before accepting a change of contact state. The binary input buffer can store up to 256 event changes between master scans. Binary input wiring connections are made to a 3.81 mm removable compression terminal block that can accept up to #12 AWG (2.5mm2) wire.


The NTX-20 includes a non–volatile, on–board UTC time/date clock, which can be synchronized via protocol or the on–board GPS satellite clock interface for precise 1ms resolution accuracy (using the optional external GPS clock/antenna).

More Information

For more information call 800.831.7223 or contact This email address is being protected from spambots. You need JavaScript enabled to view it.



NTX-20 intelligent controller Brochure PDF


ACS NTX-20 intelligent controller Product Brochure

NTX-20 block diagram Brochure PDF


ACS NTX-20 block diagram Brochure