PLC tag - AX Control, Inc.

DirectLogic 405: What You Need to Know

Close-up of a DirectLogic CPU. The DL405 D4-450 CPU is one of several CPUs in AX Control stock. — The DirectLogic D4-450 CPU

The DirectLogic 405 from Koyo is a modular controller with built-in PID instruction. End-users can add a number of different I/O modules to this low-cost controller to create configurations that meet their particular needs.

The DirectLogic 405 offers up to 3,500 local or distributed individual remote I/O points. The I/O and specific PID (proportional integral derivative control) allows command of processes like position, velocity, and temperature. One of our earlier blogs talks more about PID.

DirectLogic 405 Features

As a modular PLC, the DirectLogic 405 uses specialty and expansion modules to complete the system. This includes modules like

High-Speed Counters
PID Modules
SDS Modules
Input Simulators
4-loop Temperature Controller
Filler Modules
Interrupt Modules
Relay Output Modules
Analog Modules

The DirectLogic 405 PLC offers three CPU modules. This includes the DL430, the DL440, and the DL450. All units offer built-in power supplies and communication ports. They have built-in diagnostics, significant program memory, and a substantial instruction set. However, the CPUs vary in initialization speeds, time required to read input status, and communication request speeds. Also, I/O support may change between modules. Additionally, the DL450 has drum timers and built-in PID loops, along with extra communication ports.

DirectLogic PLC: Uses

The DirectLogic PLC supports 4-20 mA, 0-20 mA, 0-5 V, 0-10 V, 1-5 V, +/-5 V, and +/-10 V. As a low-cost controller with a wide number of application options, the DL405 is popular for many applications. It is widely used in industrial applications where data communications or RTD/thermocouple inputs are required.

A DirectLogic 405 CPU. Close-up of a DL405 D4-430. — The DirectLogic D4-430 CPU

DL405 Port Comparison

The DL450 offers more network ports than the DL430 or DL440. In comparison, the DL450 includes two network ports. These can serve as ModBus masters or slaves, or as DirectNET masters or slaves.

The DL430 and the DL440 have two built-in communication ports. Meanwhile, the DL450 has four.

Other DirectLogic 405 FAQs

At AX Control we field many questions about our DL405 inventory. Here are the answers to some of the most frequently asked questions.

Do DL405 PLCS offer Ethernet capability? Yes. Order an H4-Ecom Module if you require Ethernet.

What about Modbus protocol? If you have a DL430 or DL440 CPU, you will need a F4-MAS-MB master or a F4-SLV-MB slave module for Modbus. However, a DL450 CPU can support Modbus on port 1 or port 3.

Can the DL405 reset to factory defaults? Yes, it can. We can help with this. If you are resetting equipment in your possession, we suggest referring to directions in the DL405 manual for taking the CPU back to factory defaults.

Can AX Control provide PLC training or PLC programming manuals for DL405 products? Our staff is always happy to help our customers with whatever information we have at our disposal.

A DirectLogic 405 CPU. Close-up of a DL405 D4-440DC-1 — The DirectLogic D4-440DC-1 CPU

Our staff is always ready to help with any Automation Direct components you may need. Talk to us today.

Ladder Logic: Here are the Basics

What is Ladder Logic? A Definition

Ladder logic stems from the history of relays. At one time, relays were the primary control for most automatic systems. These electromechanical devices consisted of coils and contacts that they moved. Energized coils moved their contacts from their resting position to their active position (either closed to open or open to closed.)

Close up image of a real ladder and a light bulb. Visual representation of the inspiration basic ladder logic programming can allow for. — Ladder logic is shaped like an actual ladder, and is read from top to bottom/left to right.

In practical application, a ladder diagram showed how to wire relays together. This diagram looked like a drawing of a standard household ladder with uprights and rungs. Modern-day ladder logic still follows these conventions. Relays did (and still do) their job well, but can be cumbersome due to the sheer size of multiple relays wired together. This is where programmable logic controllers using ladder logic can be advantageous: able to do the same kind of job but in significantly less space.

Modbus: An Introduction to the Protocol

When you’re running a modern factory, you have many machines that need to communicate with each other. These conversations occur over communication protocols that integrate with whatever native ‘language’ the machines speak. However, communications must translate each language to allow other networked devices to understand them. Modbus is one of the protocols that allow this communication to occur.

Modbus gateway I/O module from Reliance Electric. — Modbus Gateway I/O Module from Reliance Electric

What is Modbus?

This is the oldest and most popular of these communication protocols. Published by Modicon in 1979, it was originally used with the company’s programmable logic controllers or PLCs. But Modicon developed Modbus as an open protocol. Anyone could use them for free without licensing. Since its original development many software vendors, manufacturers, and other groups/organizations have supported the protocol.

The communication protocol uses serial lines to send data between devices. This is as simple as a single serial cable connected to serial ports on a Master device and a Slave device. Data moves at 9600 baud (bits per second) as series of zeroes and ones. Each zero or one is a single bit. Data follows regular patterns so 8 bits identifies as a larger byte.

Modbus is a type of SCADA (Supervisory Control and Data Acquisition) automation protocol. It is now owned by Schneider Electric. It is used to help devices and equipment communicate by providing a common language all can understand. This allows for different nodes on the network to interact with request/response type messages.

What Are Modbus Communication Protocol?

The original Modbus interface used serial RS-232 communication. However, as the technology developed, options expanded to include serial RS-485, serial RS-422, and Ethernet. Formatted Ethernet packets embed Modbus messages inside, creating versatile setups. Additionally, networks designed with mixed drops can run different protocols altogether. For example, a single network could run three drops, one using MB Ethernet TCP/IP, another MB RS-232, and a third MB RS-485.