Node-RED will be used on the Raspberry Pi 4 to communicate serial Modbus RTU to a Solo process temperature controller and Click PLC using twisted pair RS485. This will be done on the same serial network so the devices will be daisy-chained together on the two wires.
We will be reading the PV (present value) and SV (set value) of the Solo temperature controller and then writing these values into the Click PLC. An SV value will then be read from the Click PLC and if it has changed, the value will be written to the SV of the Solo controller. Let’s get started. Continue Reading!
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)
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!
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!
The cmore EA9 HMI can connect to the Solo process temperature controller using the built-in RS485 serial communication port. This will connect up to 32 solo units back to the HMI for display and control.
We will be setting up our headless RHMI c-more EA9 to communicate to the Solo process temperature controller. Using the information that we have discussed previously, we will set up data logging, file transfer protocol (FTP), bitmaps, etc.
We will also set up an object library of the Solo 4896 process temperature controller. This will consist of a bitmap, numeric display, numeric edit, indication lights, and up and down increment. The system will then be controlled using the remote applications discussed last time. Let’s get started. Continue Reading!
MQTT protocol is used for machine to machine (M2M), internet of things (IoT) communication. This publish/subscribe messaging is used where limited device resources are available or network bandwidth is low. The MQTT protocol provides small size, low power usage, minimized data packets, and efficient distribution of information to one or many receivers.
The Stride MQTT Gateway is an industrial 4.0 hardware component (IIoT – Industrial Internet of Things) that provides isolation and can easily interface with existing Modbus RTU and Modbus TCP communication protocols.
We will again be connecting a Stride MQTT Gateway to a Solo process temperature controller with Modbus RTU(RS485). The MQTT Gateway will communicate to the Adafruit IO Broker. The broker can display, log, and allow us to control the data. This is done in an easily configured interface. Let’s get started. Continue Reading!