Product R413D08, USB to RS485/RS232 - documentation?

[IoTPlay]

On the product I bought, R413D08, USB to RS485/RS232, I have put in several hours now, and the lack of documentation is shocking.

Questions for this product :

1. As it has 8 outputs for controlling relays, how do I read the state of each of the relays? IN which function code (FC) will I find the info?
   FC1 Read Coil
   FC2 Read Discrete Input
   FC3 Read Holding Registers
   FC4 Read Input Registers

2. Where / how is the Slave address set / or if hard coded, what is it?

3. Starting reference?

4. Discrete output (coil) / input data types?

5. Communication. a) What baud rate does it work on. b) Data bits - 8? c) Stop bits - 1? d) Parity - none / odd / even?

6. What write values to use to switch relay on / off?

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What I have done so far:

1. Connected product R413D08 to 12v DC, and using 2 wires from A+ and B- to product RS485-MINI
2. Connected product RS485-MINI USB to Rapsberry Pi
3. Check the driver sh341 s already in the latest kernel of OS Buster - checked this with command <lsmod | grep "usbserial">
4. Checked mounting of /dev/ttyUSB0 vie
5. Added my uid to dialout, for my uid to have access to the /dev/ttyUSB0
   5. sudo raspi-config / 5 Interfacing Options / a6 Serial / enable.
6. Installed ModBus testing software to be run from ssh, with commands:
   a) wget https://www.modbusdriver.com/downloads/modpoll.tgz
   b) tar xzf modpoll.tgz && rm modpoll.tgz
   c) export PATH=$PWD/modpoll/linux_arm-eabihf:$PATH
7. Tested the above config, (but I really need the answers to above questions to try get it to work)
   modpoll -m rtu -a 1 -b 9600 -d 8 /dev/ttyUSB0

Above command gives the following:

modpoll 3.9 - FieldTalk(tm) Modbus(R) Master Simulator
Copyright (c) 2002-2020 proconX Pty Ltd
Visit https://www.modbusdriver.com for Modbus libraries and tools.

Protocol configuration: Modbus RTU, FC3
Slave configuration...: address = 1, start reference = 1, count = 1
Communication.........: /dev/ttyUSB0, 9600, 8, 1, even, t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, output (holding) register table

-- Polling slave...
Reply time-out!

[IoTPlay]

8 Channel Multifunction RS485 Module command.pdf
For the record, this is what I received via email from Luloff Rautenbach, based on my questions ....

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On Fri, 11 Dec 2020 at 10:13, Support support@robotics.org.za wrote:
Dear Client,

Bytes Number	1	2	3	4	5	6	7	8
MODBUS Definitions	Slave ID	Function	Address	Data	CRC Check
Function	Device Address	Function	Starting register address	Register length	CRC Check
Read Channel 1 State	0x00-0x2F	0x03	0x0001	0x0001
Read Channel 2 State	0x00-0x2F	0x03	0x0002	0x0001
Read 2 consecutive channels status	0x00-0x2F	0x03	0x0001-0x0003	0x0002
Read 3 consecutive channels status	0x00-0x2F	0x03	0x0001-0x0002	0x0003
Read all 8 channels status	0x00-0x2F	0x03	0x0001	0x0008

Default slave address is 01
Read Slave ID : FF 03 00 FF 00 01 A1 E4

0x0001

16 bits wide

9600 Band ,8 Data bits,None Parity,1 Stop Bit

6)Relay state0x0001 open; 0x0000 close

Attached a PDF version of the documentation that was contained in the rar files.

Opening a .rar file applications.

Linux:  unar file.rar (command line)Windows: WinRARMAC OS: The Unarchiver app

[IoTPlay]

And an attachment from the suppliers....
8 Channel Multifunction RS485 Module command.pdf

[Knaldgas]

I've found some documentation at Banggood but it is difficult to understand.

I understand that it is possible to read port levels. Is it also possible to detect a pulse? I.e. is it possible to set up the port so each read returns if the port has changed since last read?
For instance a 10ms pulse is difficult to catch by only reading current states.

If not, is the source available so I can add that functionality myself?