Tag Archives: plc programming examples

BRX Do-More PLC High-Speed Input Pulse Catch


The High-Speed Input Pulse Catch will set an output that can be seen by the PLC ladder logic scan in response to an input pulse. Inputs that are too fast to reliably be seen by the ladder logic scan time will be seen.
BRX Do-More PLC High-Speed Input Pulse Catch
The BRX Do-More series of programmable logic controllers have built-in high-speed inputs. These inputs can function in Counter, Timer, or Pulse Catch modes. Every CPU will have either 6 or 10 high-speed inputs (HSI) available depending on the model. These inputs can be used for input frequencies from 0 to 250Khz. 250Khz represents 250000 input counts per second that can be coming from devices connected to your PLC like an encoder. Due to the speed of the inputs, they function on the BRX Do-More PLC asynchronous with the PLC scan time.
We will continue looking at the high-speed inputs on our BRX Do-More PLC, by looking at the pulse catch mode. The pulse catch mode will be set up using the Z phase of our incremental encoder. Pulses will be counted using the input directly in the ladder logic and using the pulse catch bit. Comparisons will be made between the two counts and an output will be turned on when different. Let’s get started. Continue Reading!

BRX Do-More PLC High-Speed Input Counter


The BRX Do-More series of programmable logic controllers have built-in high-speed inputs. These inputs can function in Counter, Timer, or Pulse Catch modes. Every CPU will have either 6 or 10 high-speed inputs (HSI) available depending on the model. These inputs can be used for input frequencies from 0 to 250Khz. 250Khz represents 250000 input counts per second that can be coming from devices connected to your PLC like an encoder. Due to the speed of the inputs, they function on the BRX Do-More PLC asynchronous with the PLC scan time.
BRX Do-More High Speed Input Counter
We will be looking at the wiring of an incremental encoder to our BRX Do-More PLC. The A, B, and Z phases will be connected. Using the high-speed input menus in the Do-More Designer programming software we will specify the counter mode of operation. We will also scale the input so we can determine the revolutions per minute (RPM) rate. This will be monitored on our data view window. Let’s get started with the BRX Do-More PLC High-Speed Input Counter. Continue Reading!

BRX Do-More PLC to Modbus TCP RTU Remote IO BX-MBIO

The BRX Do-More 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. 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
brx do-more plc modbus remote io
We will connect the BRX Do-More 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. Continue Reading!

BRX Do-More PLC Ethernet Remote IO BX-DMIO

We will now look at the BRX do-more plc ethernet remote IO. The BRX Do-More PLC has its own line of remote input and output expansion units. You can add up to 8 I/O expansion units per controller (CPU) and 8 BRX expansion modules per expansion unit. This will make your system grow with your needs.

The remote I/O expansion units feature the following:
• All units have built-in Ethernet port, 10/100 Mbps
• MBIO units have onboard RS-485 port with removable 3-Pin connector
• Support for 8 expansion modules
• AC and DC powered units available
• AC powered units include an integral 24VDC auxiliary output power supply
• Power connector and serial port connector included
BRX Do-More PLC Ethernet remote IO
We will be looking at the BX-DMIO-M. This is the Do-More Ethernet 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!

Wiring 3 Wire DC NPN and PNP Sensors




Wiring 3 wire DC sensors can be confusing. I recently received a question on PNP and NPN sensors. They wanted an explanation of what a sink is and how to wire one. Confusion over the Normally Open and Normally Closed function of the sensor is also a common question. Several diagrams will show a resistor attached to the blue wire and a load across the others, what does it all mean?
Wiring 3 Wire DC NPN and PNP Sensors
It is quite confusing sometimes the language we use for these devices. Sometimes it is the way we talk about the sensor and sometimes about the device we are connecting. (PLC)
We will break it down and go over the wiring to a PLC input. Let’s get started. Continue Reading!

Universal Signal Conditioner and Isolator

Signal conditioners are used with analog current and voltage signals. They have the ability to change your input analog signal to another output analog signal. As an example, we can have 4-20mA analog input and change it to a 0-10VDC output signal so we can wire this into our PLC. Typically signal conditioners will also electrically isolate the input and output signals. This is either done by magnetic or optical isolation. You would usually specify the input and output signals that are required in your circuit to choose the signal conditioner required. Using a universal signal conditioner will take a variety of signals and is a great product to use in troubleshooting analog circuits.
Universal Signal Conditioner and Isolator
We will be using a universal signal conditioner to convert a thermocouple temperature input into a 0-10VDC linear output. This will be wired into the analog card of the Click PLC.
Let’s get started. Continue Reading!