Tag Archives: plc basics

BRX Do-More PLC HTTP Web Server – Website


We will now look at the BRX Do-More PLC Web Server. Ethernet equipped BRX CPUs and the Do-More Designer Simulator can now have a web server. This can be accessed by any web browser using the IP address of the BRX Do-More CPU.
A web server is server software or hardware dedicated to running this software, that can satisfy client requests on an Ethernet network. A web server can contain one or more websites and websites can have several web pages. A web server processes incoming network requests over HTTP and several other related protocols.
BRX Do-More PLC HTTP Web Server
The website built into the BRX Do-More has several different tabs that have basic information about the system, status information like warnings and errors, input and outputs, system logs, user logs, and user pages. We will be enabling the webserver on our BRX Do-More PLC and showing the information that is available. This is a great tool for troubleshooting the PLC as you will see. Let’s get started. Continue Reading!

Click PLC Real Time Clock (RTC) – Ladder Logic


The click plc has a real-time clock that will allow us to control outputs based on a date or time of day. This real-time clock (RTC) can be set from the click programming software or through the program of the controller. Our programs in the click can use the following calendar and clock values:
SD19 – RTC Year – 4 digits (2021)
SD20 – RTC Year – 2 digits (21)
SD21 – RTC Month – (00 to 12)
SD22 – RTC Day – (00 to 31)
SD23 – RTC Day of the Week – 1 Sunday to 7 Saturday
SD24 – RTC Hour – (00 to 23)
SD25 – RTC Minute – (00 to 59)
SD26 – RTC Second – (00 to 59)
click plc real time clock
We will be using the RTC – Real Time Clock in a sample program. This program will turn on an output Monday to Friday from noon until 1 pm. It will also adjust for daylight savings time. Let’s get started. Keep on Reading!

Click PLC to Modbus TCP RTU Remote IO BX-MBIO


The Click PLC can communicate to a remote I/O (input and output) controller modules using the Modbus protocol for communications. The BX-MBIO provides both Modbus RTU and Modbus TCP interfaces for remote IO. Modbus RTU is a serial communication and Modbus TCP is an Ethernet communication. Modbus RTU is supported over an RS-485 serial connection. Modbus TCP is supported over an Ethernet connection. They function as listening/replying devices (slave, server) and can connect with any mastering (master, client) device that communicates using the Modbus protocol.
Previously we looked at the BX-MBIO Modbus RTU TCP Remote IO Controller wiring and configuration.
Modbus RTU TCP Remote IO Controller BX-MBIO
BX-MBIO Hardware Video
BX-MBIO Powering and Configuring Video

We will connect the Click Ethernet PLC to the Modbus remote IO. This will be done using the Modbus TCP and Modbus RTU protocol. Ethernet and serial RS485 communication to the BX-MBIO unit will be the media.
The BX-MBIO 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
Let’s get started. Keep on Reading!

Click PLC to Stride Modbus TCP Remote IO

We will now look at the Click PLC Modbus TCP remote io. The Click 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.
Click PLC to Stride Modbus TCP to Remote IO
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 Click 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 Click 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 Click 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. Keep on Reading!

BRX (Do-More) PLC PID Ramp Soak Profile

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 Do-More Proportional-Integral-Derivative PID Instruction with PWM output that we looked at last time to apply the ramp/soak profile. This will be done on the BRX Do-More PLC.
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)
BRX (Do-More) PLC PID Ramp Soak Profile
We will be modifying our existing program from our PID with PWM Output post. Let’s get started. Continue Reading!

BRX (Do-More) PLC PID with PWM Output

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.
BRX (Do-More) PLC PID with PWM Output
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!

Click PLC PID using Factory IO (3D)

A PID (Proportional, Integral, and Derivative) control is possible with the Click PLC. A sample program was written for this PLC by Bernie Carlton in the following thread from the Automation Direct Forum. This was based on the math/process presented by Tim Wescott on is paper titled PID without a Ph.D. We will be using this sample program along with a Factory IO scene to demonstrate PID control using our Click PLC.
Click PLC PID using Factory IO
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?
Our Factory IO scene will be controlling the level of water in a tank. PID will be used to maintain the level based on a dial pot knob on the control panel. We will also discuss the math that the PID loop uses. Let’s get started! Keep on Reading!

BRX PLC INC DEC 512 Registers for DMX512

We will now look at inc and dec 512 registers using the BRX Do-More PLC. This is to control DMX512 fixtures.
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.”
 BRX Do-More PLC INC DEC 512 Registers for DMX512
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!

BRX Do-More PLC Analog Dusk to Dawn Program

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.
BRX Do-More PLC Analog Dusk to Dawn Program
We will be developing a program that will do this with our BRX PLC (Do-More). Let’s get started! Continue Reading!

Click PLC Analog Dusk to Dawn Program Example

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.
Click PLC Analog Dusk to Dawn Program Example
We will be developing a program that will do this with our Click PLC. Let’s get started! Keep on Reading!