Introduction, Product overview, Network services – Watlow NAFEM Gateway User Manual
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Introduction
This manual is intended for the user who is already familiar with the NAFEM protocol, Ethernet and
Modbus RTU. For more information see:
NAFEM Data Protocol User Manual located at:
MODBUS RTU Standard located at:
RFCs loca
Product Overview
The NAFEM Gateway has three physical connectivity points to the physical world; the device’s EIA-485
serial communication port, the RJ45 Ethernet network communication port (10BaseT) and the power
supply jack.
The NAFEM Gateway is a protocol converter that connects Modbus devices to the NAFEM protocol using
an Ethernet connection. The requirements are set forth by the selected protocols of register based
Modbus RTU for control devices and NAFEM Data Protocol [NDP] using digital signal connectivity.
This Gateway device performs these tasks with the use of six firmware components; Poll Engine, Alarm
Module, SNMP v1 Agent, Web Server, TFTP Client, and a Device Protocol Driver. In addition, a database
resides within the Gateway that contains the NAFEM Objects. This is where the information is exchanged
between the NAFEM and Modbus elements.
The function of the Gateway is to receive request for reads and writes of NAFEM Objects. These objects
are the registers within the devices. This request comes to the Gateway in the format of the NAFEM
protocol. The Gateway converts the request into the appropriate Modbus RTU packet and forwards the
information to the device. Up to 8 devices may be connected to the serial port. The Gateway can access
up to 64 registers divided between these devices. The information returned to the Gateway from the
device is converted into the NAFEM protocol and sent to the SNMP Manager or to the Web browser. The
Trivial File Transfer Protocol (TFTP) is used when program updates are sent to the Gateway or to a
device capable of flash re-programming.
Network Services
The NAFEM Gateway supports DHCP client, AutoIP, and static IP for address assignment. Normally you
will not need to make any changes. The user is able to configure preferences as to which services are
used if available. Intelligence is employed within the Gateway to revert to backup IP assignment methods
if the primary method is unavailable.