The BX-MBIO Modules are remote I/O controller modules that provide a remote input and output (I/O) using the Modbus protocol for communications. They provide both Modbus RTU and Modbus TCP interface. Modbus RTU is a serial communication and Modbus TCP is an Ethernet communication. They function as listening/replying devices (slave, server) and can connect with any mastering (master, client) device that communicates using the Modbus protocol.
Modbus RTU is supported over an RS-485 serial connection. Modbus TCP is supported over an Ethernet connection. Any Modbus RTU master and Modbus TCP client that adheres to the Modbus.Org standards, and support the function codes listed can communicate with the BX-MBIO. The remote I/O expansion units feature the following:
• RJ45 Ethernet port for communications via Modbus TCP
• RS485 serial port for communications via Modbus RTU
• Supports up to 8 additional Expansion Modules (Add the discrete or analog I/O you require)
• AC and DC powered units available
• AC powered units include an integral 24VDC auxiliary output power supply
• Power connector and serial port connector included
We will be looking at the BX-MBIO-M. This is the Do-More Modbus Remote I/O supported protocol unit. We will discuss the hardware and then connect and configure the unit to work with our existing BRX Do-more PLC. Let’s get started. Continue Reading!
The BRX Do-More PLC can use remote inputs and outputs from Stride. The Stride Field I/O Modules are simple and compact. They provide an economical means to connect inputs and outputs to an Ethernet Modbus TCP communication network. Every module operates as a standalone Modbus TCP server and can be configured via a built-in web server.
Previously we looked at the Stride Field Remote IO Modules Modbus TCP Ethernet wiring and configuration. Stride Field Remote IO Modules Modbus TCP Ethernet
– Unboxing SIO MB12CDR and SIO MB04ADS Video
– Powering and Configuring Video
We will be connecting two Stride remote inputs and outputs to the BRX Do-More PLC. Modbus TCP will be the protocol over Ethernet to communicate to the SIO-MB12CDR and SIO-MB04ADS units. SIO-MB12CDR
– STRIDE discrete combo module, Input: 8-point, 12-24 VDC, sinking, Output: 4-point, relay, (4) Form C (SPDT) relays, 2A/point, (1) Ethernet (RJ45) port(s), Modbus TCP server. SIO-MB04ADS
– STRIDE analog input module, 4-channel, current/voltage, 16-bit, isolated, input current signal range(s) of +/- 20 mA, input voltage signal range(s) of +/- 10 VDC, (1) Ethernet (RJ45) port(s), Modbus TCP server.
We will be reading an analog voltage into the BRX Do-More PLC from the remote IO unit. We will then set an output to pulse on and off at a time range indicated by this analog signal. The output will be on the other remote IO unit and will trigger the input to signal. We will look at the Frequency, Count, and Status of this input. Our BRX Do-More PLC program will also take into consideration watchdog (communication time out) and power-up events for the Stride remote input and output units.
Let’s get started. Continue Reading!
MQTT stands for Message Queuing Telemetry Transport. It is a simple publish and subscribe communication protocol that does not take too many resources.
Constrained devices with low bandwidth are ideal for MQTT. This protocol provides machine to machine (M2M) connectivity which is ideal for the Internet of Things (IoT) or Industrial Internet of Things. (IIoT)
We will be using a free on-line public MQTT broker from HiveMQ. Messages will be published and subscribed to by two clients. The first will be an MQTT Browser Client by HiveMQ. The Do-More Designer Simulator PLC will be the second MQTT Client. Information in the form of bits and words will be published and sent to both clients. Let’s get started. Continue Reading!
The purpose of a ramp soak profile is to make gradual, controlled changes in temperature (Ramp), followed by a temperature hold (Soak) period.
We will be using our Proportional-Integral-Derivative PID Instruction with PWM output that we looked at last time to apply the ramp/soak profile.
Using the immersion heater in a cup of water to keep the temperature at a constant value, we will be adjusting the profile of the temperature as we increase the setpoint (Ramp) and hold that set point for a predetermined time. (Soak) We will then decrease that temperature back to the original setting. (Ramp)
We will be modifying our existing program from our PID with PWM Output post. Let’s get started. Continue Reading!
A Proportional-Integral-Derivative algorithm is a generic Control Loop feedback formula widely used in industrial control systems. A PID algorithm attempts to correct the error between a measured process variable and the desired setpoint by calculating and then outputting a corrective action that can adjust the process accordingly and rapidly, to keep the Error to a minimum.
Here are some references on PID control: PID without a Ph.D. By Tim Wescott Understanding PID in 4 minutes PID Control – A brief introduction PID Controllers Explained Who Else Wants to Learn about On-Off and PID Control?
We will be using an immersion heater in a cup of water to keep the temperature at a constant value. Using the Do-More Designer software we will perform an autotune on our PID instruction.
Our immersion heater will be controlled through a relay using time proportional control from our PID output. Let’s get started! Continue Reading!
I was recently asked the following question after posting the Analog Dust to Dawn program:
” I was wondering if there’s an easy way to increment and decrement a range of values.
e.g. I have a range of registers (V100 ~V611) the values in each register are different. But I want to increment or decrement all the registers values by 1 at the same time. So that the ramp rate is the same.
Is that possible without having to do 6 rungs of logic for each register?
To elaborate a little on my use case. 512 registers were chosen because that equals one DMX universe. So my scaling factor is 0~255.
16 channels are mapped to two BX-08DA-2B modules to control 0-10 fixtures. All other channels are mapped to SERIO module to control DMX512 fixtures and other devices.”
We will be looking at the DMX512 protocol and how to control 512 registers at a time using our BRX PLC (Do-More). Let’s get started! Continue Reading!
A dusk to dawn sensor usually is discrete on/off of the lighting control. If we want to vary the lights to mimic more of the sunset and rise, we would use an analog output to control the lights. I was recently asked about such a program. Every day they wanted the lights to go off at 10 pm and come back on at 6 am. At 9:30 pm the lights would be on at 70% or 7volts of a 0-10V signal. In the next half hour, the program will bring the lights from 70% down to 0%. In the morning the lights will come back on within the half-hour from 0% to 70%. Poultry Farms are one place that would utilize this program.
We will be developing a program that will do this with our BRX PLC (Do-More). Let’s get started! Continue Reading!
One of the features of the BRX Series PLC is the ability to expand its capability to fit your application. Software and hardware changes are ongoing so the PLC can grow with your needs. Communication is something that the BRX PLC can do very well. As part of the internet of things (IoT), the BRX will share and exchange data. You can also refer to this as the industrial internet of things. This will suit several industrial applications.
The Do-more Updates Release 2.5.2 on April 22, 2019, has introduced new instructions. Here are the instructions that we will be using: HTTPCMD – HTTP Request / Response with Server (BRX only) JSONPARSE – Parse JSON Text (BRX only)
We will be using these instructions to read the weather conditions from a website. Let’s get started. Continue Reading!
The Productivity 1000 series of programmable logic controllers has a slim stackable super compact design. This is sometimes also referred to as a shoebox PLC because of the shape and way in which expansion modules are added. This new Productivity 1000 series PLC is the latest in the Productivity series of controllers that have hit the market.
Productivity 1000 (Stackable Micro PLC)
Productivity 2000 (Micro Modular Programmable Controller)
Productivity 3000 (Modular Programmable Controller)
These three series currently make up the Productivity Series form Automation Direct.
The Productivity 1000 series PLC provides the following features for your automation control panel.
– 50MB user memory – Can handle very complex applications easily.
– 4 built-in communication ports – Easy connectivity to your network. This would include your PC, HMI, Networks, etc.
– Data logging up to 32 GB on a microSD card
– Add up to 15 IO modules to communicate to your field sensors.
– Free Software and 30 days of free training with every CPU from Automation Direct.
– Interactive PLC Configuration Tool
– Tag Names
– Auto-discovery IO – Physical I/O tags will be generated based on each module’s position in the base. You can also reconfigure the setup and assign new tags manually.
– I/O Modules have QR codes under the wiring cover. This can be scanned so you can have the latest specifications/wiring diagrams for the module.
– Limitless PID – Autotuning – Individual or Cascade Mode – etc
– Web Server and Mobile Access
– Advanced Software instruction set
We will be looking at a lot of these features of this powerful controller. Let’s start by looking at the hardware. Continue Reading!
The program control instructions will allow us to specify what parts of the logic get solved and when this happens. This will control how the PLC will scan and solve your logic in your program using a synchronous PLC Scan. Understanding the PLC program scan will explain the synchronous and asynchronous program scanning. Ladder logic programs get solved left to right, top to bottom. The result of the rung before is available for the next rung.
Using programs, tasks and subroutines in our BRX Series PLC we can divide up our program into smaller segments. This will help when we troubleshoot the system in the field as the system integrator. Let’s look at some samples of each of the above mentioned methods. Continue Reading!