How to split the DF1 Port of SLC500, MicroLogix, CompactLogix, PLC5, ControlLogix or any Allen Bradley DF1 Port Device.











In case you have the serial DF1 port of an Allen Bradley PLC, like PLC5, SLC 5/05 1747-L551, SLC 5/03 1747-L533, CompactLogix 1768, CompactLogix 1769, Control Logix 5563, MicroLogix 1400 (1766 MicroLogix ), MicroLogix 1200 (1762 MicroLogix ), MicroLogix 1100 ( 1763 MicroLogix ), MicroLogix 1000 ( 1761 MicroLogix ), or any DF1 device where the DF1 port is already being used and you want to connect another DF1 device to it, usually you would get the Allen Bradley 1747-DPS1 DF1 port splitter but that is being discontinued by Allen Bradley and now your best solution out there is Equustek’s DL4000-DFX  which allows three DF1 serial devices to simultaneously communicate with each other, below is the link to DL4000 page .

The DL4000 can be programmed with other firmware versions to perform other protocol conversions, such as; 

DL4000-DMX allows DF1 to communicate with MODBUS  and can be configured for MODBUS master or MODBUS slave, it also can be configured to connect via RS232, RS422 or RS485.

DL4000-MMX interfaces MODBUS  RTU to MODBUS ASCII (Allows Modbus RTU devices to communicate with multiple Modbus ASCII devices), also can be configured to do RS232, RS422 or RS485.

DL4000-DAS Interfaces serial ASCII devices (Scanners/Printers) to AB DF1 protocol.

DL4000-MAS Interfaces ASCII device to MODBUS RTU Slave.

DL4000-PM Provides a DF1 Half Duplex Master Interface to Allen Bradley Power Monitor 3000 then sends the converted data via Modbus to specified Slave RTU devices.

Equustek’s DL3500-DF1/DH+, a direct replacement for Allen Bradley’s 1770-KF2 or 1785-KE, DF1 to Data Highway Plus (DH+) Interface

image1Many Allen Bradley PLCs, like MicroLogix 1400 (1766 MicroLogix ), MicroLogix 1200 (1762 MicroLogix ), MicroLogix 1100 ( 1763 MicroLogix ), MicroLogix 1000 ( 1761 MicroLogix ), CompactLogix 1768, CompactLogix 1769, SLC 5/05 1747-L551, SLC 5/03 1747-L533, and other manufacturers Distributed Control Systems (DCS), like the Honeywell DCS (TDC 3000) or the Emerson DeltaV DCS with PSIC (Programmable Serial  Interface Card) that have a serial RS232 DF1 port, most of the time they need to communicate with an Allen Bradley Data Highway Plus (DH+) device like the PLC-5, SLC 5/04, ControlLogix 1756-DHRIO, a Panel View, or any other DH+ device. The solution for that used to be using one of Allen Bradley’s 1770-KF2 or the 1785-KE to interface between the DF1 and DH+ by connecting the DF1 side to the RS232 DF1 port, while the other side (DH+) would be daisy chained to the Data Highway Plus Network, but Allen Bradley phased out the 1785-KE and 1770-KF2, both now are obsolete. So what options are out there for the plant to continue working until they are ready for an upgrade to Industrial Ethernet IP?

The Equustek DL3500-DF1/DH+ is a direct replacement for the Allen Bradley 1770-KF2 and the 1785-KE, in all those cases previously mentioned, the DL3500 will be transparent where any of the above mentioned PLCs or DCS will look like any other DH+ device or PLC node on the Data Highway Plus Network allowing communications between all of them.

An application note showing how to setup and configure the DL3500 DF1 to DH+ allowing a MicroLogix 1000, SLC 5/05 1747-L551 and a SLC 5/03 1747-L533 and make them communicate like any other DH+ PLC on the Data Highway Plus Network ( DH+ ) then using RSLINX and RSLOGIX 500 to go online with them, are available from this link.

In any case, when you have the discontinued Allen Bradley legacy 1770-KF2 or the 1785-KE damaged by lightning or any other failure and needs to be replaced, your best solution is the Equustek DL3500-DF1/DH+, as it is a direct replacement for the AB 1770-KF2 and AB 1785-KE.

Similar to Allen Bradley’s 1770-KF2, 1785-KE and 1784U2DHP, the DL3500-DF1/DH+ will allow your PC HMI SCADA running with any RS232 DF1 driver or RSLINX 1784U2DHP driver to communicate with and go online with all DH+ nodes (PLC-5s & SLC 5/04s) that are connected to the Data Highway Plus network where the DL3500 DH+ port is connected to as well.

The DL3500 DF1 side has many physical options to connect serially though RS232, RS422, RS485 & USB with baud rate setting configurable range from 4800 to 115200 baud and the DH+ with baud rates of 57.6KB, 115.2KB and 230KB, the DL3500 can be powered from the USB or an external DC 9-27V.

More details and other application notes on Equustek DL3500 can be found from this link.


MicroLogix 1400 MODBUS TCP/IP to DH+ 1785 PLC-5 or 1747 SLC 5/04

image1If you are in a situation where you have an Allen Bradley MicroLogix 1400 with MODBUS TCP/IP support, and you want it to communicate with the DH+ network devices like Allen  Bradley’s PLC5 and SLC5/04, where the MicroLogix Ethernet port is configured for MODBUS TCP/IP Master so that it can get data from any DH+ Device ( PLC5s and SLC504s), or the other way when the DH+ Nodes or devices like PLC5 or SLC5/04 wants to get data from MicroLogix which it’s Ethernet port is configured in this case for MODBUS TCP/IP Slave, that said not many easy affordable solutions are out there, however Equustek Solutions DL6000-MEDH+ can do it easily, when it is configured as a Slave where the MicroLogix is Ethernet port is configured as a Master.

Here the DL6000-MEDH+ will allow the MicroLogix to communicate with all PLC5s and SLC504s or any Allen Bradley DH+ node connected to the same Data Highway Plus network which the DH+ port of DL6000-MEDH+ is connected to, that is accomplished when the MicroLogix MODBUS connects to the IP address of the DL6000-MEDH+ then by using the DH+ nodes address numbers as MODBUS Slave IDs to address the PLCs and SLC504s.

Also when the DH+ PLC5s or SLC 5/04s are initiating communications and are requesting data from the MicroLogix then the DL6000-MEDH+ Ethernet side will be configured as a Master while the MicroLogix Ethernet port will be configured as a MODBUS TCP/IP Slave.

Here the DL6000-MEDH+ will allow any DH+ device to request data from the MicroLogix.

More details about the DL6000-MEDH+ can be found from the link below.

DL6000-MEDH+ as A Master Application Note link below

DL6000-MEDH+ as A Salve Application Note link below


What is a protocol converter in networking?


In networking, a protocol converter is a program or a device that converts from one protocol to another allowing inter-dependability between systems or devices that use dissenting protocols. Essentially, communication protocols are the rules that define how the data passing through a system are to be processed and transmitted. If two or more systems or devices don’t use the same protocol, then they cannot understand (communicate with) each other; thus the need for a protocol converter.

In simple words, a protocol converter converts from protocol to another in order to permit the systems to achieve interoperability.

The protocols are software installed on routers that transfer commands from one system to another. The process incorporates conversion of data, commands, their encoding, demonstration and enclosing to accomplish the transformation.  

There is a whole host of protocols used in numerous fields of networking that includes events and time synchronization, conversion of data messages, major protocol translation messages involve commands, AMR, automation, utilities, transmission and distribution, power generation, oil and gas, and remote monitoring applications.

A protocol converter works by utilizing an internal master protocol for communicating with the external devices. The data collected is then used for updating the converter’s internal database. There are numerous physical mediums used for communication on protocol-X and Y including the Ethernet, RS-232, and RS-485 among others.

Types of protocol converters

There are primarily two types of protocol converters used in networking. They are:

  1. Software Protocol Converters
  2. Hardware Protocol Converters

Choosing a protocol converter

When choosing a protocol converter, it is critical to go for a converter that best suits your communication and application setup. The following are the three factors to consider when choosing a protocol converter.

  • Total number of connections: Some protocol converters have only single connections, while others have as many as 32 connections including multiple serial ports.
  • Connectivity protocol: The protocol converter must support the protocol used by your network whether Ethernet, RS-232, RS-422 or RS-485.
  • Baud Rate: The protocol converter you choose must have high baud rates for high performance.

Applications of a protocol converter

The applications of a protocol converter differ from industry to industry. Depending on the protocols, it can be a software converter or a hardware converter. Some of the key applications of a protocol converter include building automation, vehicle automation applications, automatic meter reading, process automation, industrial automation, and substation automation.

In situations, where a signal from the system or device is inept at coexisting with the protocols used by the network management system or building management system, a protocol converter is best suited.

A protocol converter can receive up to a maximum of 1024 inputs over 32 modules, allowing for flexible integration with multiple alarm and management systems using a single device. On the other hand, the protocol converters are used with fiber media converters, PDH multiplexes, PCI Express network cards, DWDM equipment, CWDM, and switches.

Final Words

All in all, protocol converters play an essential role in telecommunication and networking applications.  

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DL3500 General Operation & Applications

DL3500 General Operation & Applications

The DL3500 continues the functionality of the DL2000/DL3000 product line. It offers both the new addition of DH485 as well as a plug and play USB interface. As well as having the DH+ and 232/422/485 capabilities of the DL3000. Two DL3500 Models will also allow Bridging between DH+ and DH485networks. New is the ability to power the DL3500 from the USB communication link, removing the sometimes cumbersome procedure of location an AC or DC power supply when using laptops or PC’s inthe field.

The DL3500 has two communication ports. Channel A is designed to connect to you industrial network,either AB DH+ or DH485 networks. Channel B is used to connect to your serial or USB device, the protocol depends on which flavour (model) of the DL3500 you have ordered.

Channel B has the capabilities of RS232C, RS422, RS485 and USB 2.0. Configuration of the operating parameters is done quickly and easily by the DL32 V3.X windows based software shipped with the unit or available on the Equustek Website. Currently there are three standard DL3500 products available to allow access to A-B’s DH-485 and DH+ network.

Many other custom ASCII and serial protocols have been implemented to Both DH+ and DH-485 on the DL3500 platform. Contact Equustek Solutions to see if the DL3500 is the correct device for your communication needs.

The DL3500 has all three models below available in DH+ and DH485 flavours:

The DL3500-Modbus is a two port device that bridges your Modicon Modbus devices to ones on an Allen Bradley DH485 or DH+ network. The Modbus model can either be used as Modbus Master or Modbus Slave as well as having both Modbus ASCII and RTU protocols.

The DL3500-DF1 is a two port device that allows your DF1 devices (either Full or Half Duplex protocols) to ones on an Allen Bradley DH485 or Allen Bradley DH+ network. The DF1 model is a direct replacement for the 1770-KF3 for DH-485 and 1770-KF2 for DH+ and allows your PCs or Laptops access to any node on the corresponding A-B network.

The DL3500-ASCII interfaces Serial ASCII devices (Scanners/Printers) to SLC’s or other devices on an Allen Bradley DH485 or DH+ network. The DL3500-DF1/DH+ or DH485 interfaces your DF1 devices (either Full or Half Duplex protocols) to ones on either an AB DH485 or DH+ network. The DL3500 comes with both networks available with only using the software configuration program to switch between the DH485 and DH+ networks


DL4000 General Operation & Applications

The DL4000 hardware platform was designed to be used as a smart Serial to Serial converter. It comes in a DC powered Din-Rail Mountable compact cabinet for ease of portability and installation. Standard protocols such as Modicon Modbus and Allen Bradley’s DF1 exist already. Other protocols and operations are easily programmed per customer’s requests.

The DL4000 has three serial channels, CHA, CHB, and CHC for intermixing protocols and communication standards. RS232C, RS422 and RS485 are available on CHA and CHB, while CHC only does RS232. Configuration of the operating parameters is done quickly and easily by the DL32 V3.X for all DL4000 models except DL4000-DMX use EQ32, both EQ32 and DL32 are windows based software shipped with the unit or available on the Equustek Website. Currently there are five standard DL4000 products available and many other customized ASCII protocol interfaces have been done.

Contact Equustek Solutions to see if the DL4000 is the correct device for your communication needs.

The DL4000-DMX is a two port device that bridges your Modicon Modbus devices to ones using the DF1 protocol. The DMX can either be used as Modbus Master or Slave as well as having both Modbus ASCII and RTU protocols.

The DL4000-DFX is a three port DF1 device. This will allow Two DF1 devices to talk to one CH0 of a PLC or SLC. The ability to intermix Half-Duplex and Full Duplex, or RS232 and RS422 greatly improves the effectiveness of the PLC’s CH0 programming port

The DL4000-MMX allows Modbus RTU devices to communicate with multiple Modbus ASCII devices. The DL4000-DAS interfaces Serial ASCII devices (Scanners/Printers) to A-B’s DF1 protocol.

The DL4000-MAS interfaces Serial ASCII Scanners to Modicon’s Modbus Protocol. The DL4000-MAS acts as a Modbus Master device and writes the ASCII data to a specific register in a specified slave device.

Using Wonderware’s ABTCP driver with the EQ7000

Wonderware’s ABTCP IO Server is capable of reading and writing data to devices on the DH+ using the EQ7000. Before any data can be read or written, a new local host must be created in the host file and a topic must be defined in the ABTCP IO Server.

Configuring the Hosts File The hosts file contains the names of local hosts and the IP addresses that are assigned to them. You must add a new entry to the hosts file with the IP address of the EQ7000. Below are the steps to adding a new entry to the hosts file.

1. Locate and open the hosts file. The host file can be found in the following directory. C:\WINDOWS\system32\drivers\etc

2. Open the hosts file using a text editor like Notepad. You will see the following.











3. Add a line at the end of the file specifying a new host name and IP address and then save the file. In the example below, the host name EQ7000 is added and has an IP address of









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Communicating via Allen Bradley Ethernet ip protocol


The EQ7000 can accept messages sent by the Allen Bradley ethernet ip protocol. Therefore devices capable of communicating using Allen Bradley ethernet protocol can access devices on the DH+ network. Browsing specific nodes on the DH+ network is possible using RSLinx.


To do this, an Ethernet driver must be configured in RSLinx gateway with the IP address of the EQ7000 mapped to each node that exists on the network. Sending Messages to DH+ devices To communicate to nodes on the DH+ network using AB Ethernet switch, remote messaging must be used. Using local messaging will only allow communication to a single device located at node 0 on the DH+. When using remote messaging, the source and destination link ID’s are not needed and can be left as 0. The destination address (or remote address) will be the value of the DH+ node address. Please note that DH+ uses octal notation and the application that is being used to setup the message may use decimal notation.Below is an example of how to setup a remote message in a SLC 5/05 to read data from node 7 on the DH+ network through the EQ7000 at