The Productivity 1000 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
We will connect the Productivity 1000 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!
PID Ramp Soak Instruction
The purpose of a ramp soak instruction 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 that we looked at last time to apply the ramp/soak instruction.
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 set point (Ramp) and hold that set point for a predetermined time. (Soak)
We will be modifying our existing program from our PID loop instruction. Let’s get started. Continue Reading!
PID Loop (PID) Instruction (Auto Tuning)
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.
The following links will explain the PID instruction. https://www.csimn.com/CSI_pages/PIDforDummies.html http://www.ni.com/white-paper/3782/en/ https://en.wikipedia.org/wiki/PID_controller
We will be using an immersion heater in a cup of water to keep the temperature at a constant value. Using the Productivity Suite 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!
Secure PLC Email messaging is now available in the latest version of the Productivity Programming suite. SMTP or Transport layer security (TLS) email with an attachment and/or latest data log files can be sent. To be able to use this feature you must have installed Productivity programming suite v3.4 or higher and then load the latest firmware to the Productivity CPU. We can set up 4 different accounts in our PLC project. Account templates are already installed for some of the more common email servers.
We will be sending an email using a Gmail account with authentication. This will also include attached logged data files, error and event files. Our message will also include a switch and register current values when sending our email. We will also discuss how the PLC can send a text (SMS) message. Let’s get started. Continue Reading!
The productivity series of PLCs comes with 4 built-in communication ports for easy connectivity to your PC or various industrial networks. Ethernet protocols like Modbus TCP can be utilized with the RJ45 port on this PLC. Modbus TCP is an open (published) protocol that uses the Server (Master) / Client (Slave) architecture. It’s a very common protocol used in industrial automation controls.
We will be using the RJ45 (Ethernet) port to communicate to a Click PLC. Modbus TCP will be the protocol used on this Ethernet communication media. The Productivity 1000 PLC will be the server and the Click PLC will be the client. We will be creating a network between the two PLC units. A heartbeat will be used so if communications is lost, the server (slave) will know. The throughput time will be timed by using a small program in the Click PLC. You will soon see how the Productivity Series of PLC’s is the best way to handle communication to other devices. Let’s get started. Continue Reading!
The productivity series of PLCs has a built in data logger. This easy data logger will log up to 64 tag values on a USB (Micro SD) storage device connected to the CPU. The logs will be stored in CSV (Comma Separated Values) file format. Logging can be triggered by the rising edge transition of a Boolean tag (event) or configured to occur at regular intervals (scheduled).
A USB storage device should be normally connected if logging data. The CPU maintains an internal 73KB buffer for temporarily logging data while no USB storage device is present. Data in the buffer will not be retained through a power cycle. Let’s get started. Continue Reading!