This cheap relay module arrived with no user manual, no operating instructions, no datasheets, and no technical support. The holding registers can also be read but I had no need to do this and have not included doing that in this example. No surprise, we often come across sellers who do not understand anything about what they’re selling!

Read more about the condition New: A brand-new, unused, unopened and undamaged item in original retail packaging (where packaging is applicable). IN3-GND (default is high level, low level after the switch is turned on) the computer sends instructions to read the switch status. We’re obliged by EU General Data Protection Regulation to let you know about this right; we don’t actually intend to misuse your data.The rest of the code in the loop() just turns on each of the 16 relays one at a time then turns them on one at a time then toggles 16 randomly selected relays turning them on if they are off and off if they are on.

I found the module relatively straightforward to use, and it seems to do a good job of allowing one to simply control two devices independently using Modbus RTU protocol. I have done tests with another controller (similar to OH) and I have gotten it to work with the FC6 function.Welcome to my quick review of an inexpensive 2-channel 5V relay module controlled via RS485 bus utilizing Modbus RTU protocol. Please take a moment to review our updated Terms and Conditions, describing what information we collect, how it is used, and how you can control the use of your data.

Modbus RTU is limited to a single master, that means, only one set of signals can be on the RS485 link at any one time. It is also recommended to purchase USB TO RS232/485/TTL or USB TO RS485 at the same time for easy testing. Modbus RTU command are send through upper PC software (like:ModbusRTU configuration Tool ),CRC check code is auto generated, if want use serial debugging software (like SSCOM )to test Modbus relay module then need manually generated. Remember to check back daily for new updates with the wide selection of relay, you're bound to find a couple of options you will like!LC 8-way Modbus relay module equipped with mature and stable 8-bit MCU and RS485 level communication chip,adopt standard modbus RTU format RS485 communication protocol ,It can realize 8-way optocoupler input signal detection and 8-way relay output, can be used for digital detection or power control occasions. Modbus device through receive from external control terminal (like Host computer/MCU ) Modbus RTU instruction to perform related operations, one frame instruction generally consists of device address, function code, register address, register data, and check code,frame length is related to function code. To make your hunt for modbus relay easier, utilize the multiple filters to narrow down your selection. Its AC plug may be changed, so please specify the type of the plug you want to use and we will send it with this AC plug. There are lot of profesional ModBus software apps for this usb relay board allowing to be easily integrated in any ModBus automation project.