How to connect our USB-RS485 adapter to the ACE-GTW-MQTT or ACE-GTW-4G

 

Our ACE-GTW is dedicated to our ACE PLCs. It communicates with ACE PLCs via their USB ports. However, if you wish to use our low-cost ACE-GTW gateway to connect to an RS485 network, simply add an FTDI USB-RS485 converter. You’ll find one in our online store.

We are going to connect our HMI RS485 port to the Gateway via the USB-RS485 converter.

For our HMI connected to a RS-232 converter, you must choose a FTDI version, SubD9 female, with TX on pin 2, RX on pin 3 and GND on pin 5. No signal on other pins. The other pins can enter into conflict with the RS485 pins present on the HMI SubD9.

In our example, the USB-RS485 converter will be connected to:

• the USB port of the ACE-GTW gateway (Master Modbus)
• HMI RS485 port (Modbus slave in this case)

For the wiring, please, see Wiring diagram of the serial RS232/RS485

HMI COM		USB RS485 Converter	Colours
Sub-D9 – PIN 9 – A+	< >	A+	Orange
Sub-D9 – PIN 8 – B-	< >	B-	Yellow
GND – PIN 5	< >	GND	Black

With our USB-RS485 converter, Brown and Green is a 120 Ohms terminal resistor

 

Modbus RS485 slave device configuration (here our HMI)

In HMI-Tool, add a Slave Modbus port to the COM1 or COM2 port. Leave the other settings as defaults.
Add a “Numerical Input” on HMI screen. Enter the LW100 address, which is a word in the HMI’s internal register.

 

ACE-GTW Gateway : Topic configuration

Connected to the Gateway, the default address is http://192.168.8.1 Your MQTT Gateway must be already connected to a Internet and a MQTT Broker See the Quick start tutorial No need to configure the USB-RS485 converter in the ACE-GTW gateway- it’s automatically recognized Add a new MQTT topic with parameters on the screenshot Congratulations! Now, the ACE MQTT Gateway is able to read the value from the HMI and to publish it to MQTT Broker