Recent content by jschulze

It may not be a problem if the networks use the same subnet. You could use a layer 2 VPN bridge to connect them as if they are all on the same, local subnet. Of course, the actual problem is if the equipment on one site uses the same IP addresses as the equipment on the other. Then this approach...

You may be able to use the ICC Mirius gateway in conjunction with larger relays that accommodate the 400V 25kW 3Phase requirement. http://www.iccdesigns.com/protocol-gateways/66-mirius.html The Mirius can be configured as a Modbus RTU Master and has 2 dedicated I/O channels that can be...

Can you clarify your requirements? "Poll one MODBUS register continously" seems to imply you're looking for a Modbus client/master device as opposed to a server/slave device. Is this correct? What version of Modbus do you need (serial Modbus, such as Modbus RTU or Modbus ASCII, or Ethernet...

It's unlikely anyone here will be familiar with the data logger software you're using. Therefore, I recommend you diagnose and troubleshoot this issue using Modbus Poll only, which many users here have used and are familiar with. In addition, Modbus Poll allows you to view and log the...

ModScan will open a Modbus/TCP connection and keep it open while making requests (it does not close the connection after each request/response). Therefore, it sounds like the ABB is closing the connection prematurely. You may need to change your Modbus TCP/IP Server Settings on the ABB. Take a...

As long as the RTU has more than one serial port, it seems you can run Modbus Slave and Modbus Master simultaneously. Note that at least two serial ports are required because Modbus only allows one master on each RS-485 bus. From my brief research into the Brodersen equipment, it seems they are...

Well, to be blunt, if you're implementing this yourself, the behavior is going to be exactly what you coded it to do (after all, computers only do what you tell them to do). It seems currently, you've implemented it to unconditionally reuse sockets, thus dropping a previously established socket...

I think that might be your issue. I can't find any documentation or indication online that the LZQJ-XC or VARIOMOD-XC support the Modbus protocol. If you need Modbus with the LZQJ-XC, it seems you may need to use the LKM614 from REDZ instead of the VARIOMOD-XC. However, I would recommend...

This statement is not true. I just provided you with an example in my previous post of real-world INPUTS (a flow sensor) and OUTPUTS (relay contacts) connected to a flow meter and how those would map to Input Registers (INPUTS) and Coils (OUTPUTS) on Modbus. I did not provide you with any of...

Take a look at these excerpts from the Modicon M340 User Guide and Sepam Series 20 User Guide.

Another follow-up question. What module are you using with the EMH meter to provide RS-485 Modbus RTU? Are you using the VARIOMOD-XC from EMH or another module, such as the LKM614 from REDZ?

Thank you for the additional details. Can you please describe or provide a diagram of how you have your EMH meter wired to your RS-485 to USB converter? What happens if you swap your + and - wires at one end? Can you tell us what Modbus software you're using on your PC. Please also include a...

I believe you're thinking about it on too wide of a scope. Don't think about it from a communication perspective or from your whole system (i.e. one device sending values to another device, etc.). The Modbus slave alone defines whether specific data is INPUT data or OUTPUT data. INPUT data is...

Performing a Google search for "MIL 1553 to RS-485 gateway" turned up this device: https://www.mil-1553.com/macc-communications-converter Perhaps that would work for your needs?

I believe these are the only connections you need to make: Dtech Adapter Netbiter T/R+ (DB9 pin 1) A T/R- (DB9 pin 2) B GND (DB9 pin 5) GND (VDC-) No wires need to be connected to RXD+ (DB9 pin 3) and RXD- (DB9 pin4) on the Dtech adapter.