SPRUTNET PRO BGS2 modem for automation

Telemetry of remote objects via GSM modem SPRUTNET PRO BGS2

What are modems for? The question is more rhetorical.
To transfer data from point A to point B, without spending time and effort on physical movement, is their main purpose. Consider the problem of taking readings from metering devices via the GSM channel, which is relevant for many.

Of the many models on the market, SPRUTNET PRO BGS2 was chosen, primarily because of the relatively low price - 3900 rubles, and secondly, the developers offer free samples for testing. Another plus is that there is no need to purchase two modems to organize a communication channel - it is only needed directly at the facility, and special software is installed on the operator side, which converts incoming TCP connection packets into a virtual COM port, to which you can already connect any user program.
The main argument that convinced me to choose this particular model was the presence on Sprutnet PRO of two communication interfaces with external equipment at once - RS232 and RS485. Due to the fact that the modem was supposed to be installed on the heating unit of an apartment building, where there are devices with both interfaces, the choice was made.

To order a modem for testing, you can chat directly on the SPRUTNET PRO BGS2 website with a pleasant and technically competent manager who will help you choose the right model. For example, I needed a modem with data transfer via GPRS, although someone might be more suitable for a model using a CSD connection.

So, the package has arrived, the modem is on hand - let's start the experiments. In appearance, it is made quite soundly, a metal case, connectors for external connections under the screw. My modem has two slots for SIM cards, i.e. the possibility of redundant communication channel is provided
The modem is configured via the USB interface, for which you must first install the driver from the download page. In general, developers have an order with documentation and software, you don’t need to look for anything separately, everything is in one place.
To configure, you need to remove the SIM card from the modem, otherwise, when it is turned on, it will go into operating mode. All setup is described in the documentation, it takes a couple of minutes. During the configuration, an unexpected fact was revealed - in the line of the IP address with which the connection is established, a static, white address must be indicated! So be it, the obstacle is quite surmountable.
For the sake of experiment, I checked whether the connection would be through a gray dynamic address. Yes, everything works, BUT until the next reboot of the router, after which you need to re-enter the new connection address into the modem - not the best option. The problem was solved by registration with the provider under the contract of a dedicated IP. In Rostelecom, this service costs 130 rubles. when connected and further 80r. per month. By the way, I also tried to go out through VLAN, but the problem is that the ports needed for the exchange could not be transferred in this way. Maybe there is a way, but time is money, so it was easier to negotiate with the provider.
So, the modem is configured. It remains to install the necessary software on the PC. This software is based on the developments of Eltima and is essentially a paid product, but if you wish, you can find demo versions. I recommend talking to Sprutnet technical support, they helped to choose the right version of the IP adapter, which was not on the site.
 As a result, when launched, this utility hangs in the tray and creates two interconnected virtual COM ports. One receives packets from an external TCP connection, the other is directly connected to any user program - hyperterminal, meter interrogation software or SCADA system.
That’s all. It remains to supply power to the modem and observe the process of establishing a connection. To check, manufacturers recommend hanging an external jumper between Tx and Rx (pins 2 and 3) on the connector.
Some time after the start of the IP adapter, a message about the connected modem appears in the log. To check the connection, you can run a hyperterminal, in the connection properties of which the second port from the connected pair is specified, in the figure this is COM8.
By pressing the buttons on the keyboard, we get a return echo through the jumper on the modem with some delay. On the modem, when the connection is established, the red indicator is constantly on.
The channel is working, now you can connect external devices.
In my case, this is a VKT-7 heat calculator and a TPM32 heating controller produced by OWEN. Communication with the first is carried out via the RS232 interface, with the second - via RS485. By the way, initially this device was purchased from the factory in a budget version - without communication interfaces, I had to install the missing elements, since the firmware is the same for both options.
To interrogate both devices, there is no need to reinvent the wheel, manufacturers have taken care of various software options for taking readings, up to and including OPC servers. For example, for VKT-7, all the necessary software can be found on the website of the developer or dealers. The same applies to TPM32, which is present in the list of supported devices in the OWEN OPC server.
The only caveat is that these devices must be interrogated, of course, in turn, because. interfaces 232 and 485 on the modem essentially occupy one channel and differ only in circuit design.

It is too early to draw generalized conclusions, the modem is installed at the facility, further operation will show all the pros and cons.

Author: Anisimov Sergey (sa104@mail.ru)

#SprutnetPRO, # interfaces, #communications, #RS232, #RS485, #heatingunit