Homebrewed software to communicate with measuring device via Modbus TCP

Dear gentlemen, dear jschulze,

Prior to get ordered and purchased relay output module,
as my computer lacks any rs232 or rs485 port, in order to convert usb to rs485 I posess this converter. Just please have a look at the picture below:
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and the rear side with toggles to switch operating mode:
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How do you think, is it sufficient to deal with this converter, or do I need to seek and buy another one?
Faithfully,
N. Qv.
 
The converter seems like it should work, but you should test it with known working RS-485 device.

For RS-485, be sure to set the DIP switches properly for RS-485 and connect your wires to the B-, A+, and GND terminals (I believe the TXD and RXD terminals are for RS-232 mode only).

According to the text on the converter, it appears you want DIP switches 3, 4, 8, 7 ON and 1, 2, 5, 6 OFF for USB to RS-485.
 
Dear jschulze,

As you kindly suggested to compare Adam 4068/4069 to WP 8025 RO I read the set of commands relevant to each one.
I found Adam 4068/4069 supports wider set of commands compared to WP8025RO.
Though among commands for the first as it mentioned on page 83, table 4.17 the "Syncronize samples" and "Read Syncronized Date" are disabled. I have been reflexing what could be the use of those functions?
Also I read that the 4069 module features two additional commands: "Read low pow state" and "Set low pow state". This, as I get could be essential when remotely controlling some distant site to see that power on module is low etc.
The most essential command among others could be "Write safety value" and "Read safety value", if I got it right this implies, that features the latch to prevents module contact(RO) from undesired or accidental trip when module is powered on-off or experiencing communication problems? Did I get it right?
But stil, is the set of commands of Adam 4068/4069 in some means applicable and relevant to WP8025RO? For example, if someone inputs $AAM "Read Module Name" would wellpro module return module name?
The most pleasant surprising thing for me that WP8025RO provides feedback that tells user whether command is accomplished or not, and therefore, as I get, there is no need to buy additional digital input module to check the state of contact(closed/open).

Having reflexed on this for a while, I decided to purchase WP8025RO that would be sufficient introduction.

Faithfully,
N. Qv.
 
Unfortunately, I am by no means an expert with these I/O modules. If you have specific questions regarding their operation, I recommend you contact the vendors directly.

But stil, is the set of commands of Adam 4068/4069 in some means applicable and relevant to WP8025RO? For example, if someone inputs $AAM "Read Module Name" would wellpro module return module name?
The Advantech commands are not compatible with any other vendors' product. The ADAM 4068 module supports two protocols, a proprietary ADAM ASCII protocol and Modbus RTU. The WP8025 supports only Modbus RTU.

The most pleasant surprising thing for me that WP8025RO provides feedback that tells user whether command is accomplished or not, and therefore, as I get, there is no need to buy additional digital input module to check the state of contact(closed/open).
I think you're simply referring to the fact that you can read the Modbus Coil in addition to writing it. This is typically true of almost all Modbus devices, including the ADAM modules (when using the Modbus RTU protocol). However, note that this only provides feedback of the logical state of the contact, which under most conditions will correspond to the physical state of the contact. But if there is damage, malfunction, etc. the module's physical state of the contact may differ from the logical state.
 
Dear jschulze,
As I intended I have ordered on AE store the WP 8025 RO module.
They commenced with my order on Thuersday and it possibly arrives within November the 1st time span.
Today I have finished with reading the ADAM 4000 series manual which you kindly passed me.
My perception is that it is usefull to read it even though I have chosen Wellpro.
On the mapping table of Modbus protocol for ADAM 4068 module, page 268 it is not clear for me:
1. What is the mapping table of Modbus protocol indended for? And how it could be useful for user?
2. What is ADDR 4X and ADDR X columns stand for, and what is 4X and X factor intended for?
3. What is MEMO column contence for?
4. How to handle this "Mapping table for Modbus Protocol"? What sort of work could be done with its use?
Please have a look at them below:
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5. What are these rectangles with arrows above, what do they denote or designate?

Faithfully,
N. Qv.
 
Well, first off, no it is not useful to read another product's Modbus manual if you will be using a different product. You need only be concerned with the manual of the product you're actually using.

But since some of your questions are applicable to other Modbus devices, I'll try to give an answer.

1. What is the mapping table of Modbus protocol indended for? And how it could be useful for user?
A Modbus mapping table, a.k.a register list, details what Modbus registers (Holding Registers/Input Registers) or discretes (Coils/Discrete Inputs) are accessible via Modbus. This is the only way a user knows what data can be accessed on a device, and how the data is accessed.

2. What is ADDR 4X and ADDR X columns stand for, and what is 4X and X factor intended for?
This is standard Modbus reference notation. As follows:
0X - Coils
1X - Discrete Inputs
3X - Input Registers
4X - Holding Registers

Take a look at this thread for an in-depth description of Modbus register numbering.
https://control.com/forums/threads/modbus-register-numbering.49844/

3. What is MEMO column contence for?
Many times there is a MEMO, NOTES, or DESCRIPTION column in Modbus register tables that give additional detail on the possible values or behavior of the data. If the data is fixed, the fixed value will be shown here. If there are specific meanings to different values, they will be listed here. If there is any scaling done on the value, it will be detailed here.
 
Dear jschulze,
Today I got received the small parcel with my wp8025ro module included!
I am so pleased to posess it now, after so many days expected for!
wp1.PNG
wp2.PNG
wp3.PNG

Since a while, I have been reflexing on aproach to develop some homebrewed software to make its relay contacts closed and opened upon commands manually issued from PC.
Can you briefly take me to understanding of objective chosen, to have my further activities directed properly?

Your faithfully,
N. Qv.
 
I recommend first following the instructions in the WP8025ADAM manual for using Wellpro's PC debugging tool to confirm operation between your PC, USB to RS-485 converter, and the WP8025ADAM module.

Next I recommend trying a third-party Modbus tool, such as Modbus Poll, to read and write the 8 Coils (0X type), 1 - 8 (1-based addressing) that correspond to the 8 relays.

Then move on to creating your own software.
 
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