Northen lights over the Motala bridge

Monitoring & Control

With remote monitoring and control features, operators can access real-time diagnostics, performance metrics from a central location, significantly reducing maintenance costs and downtime – making them superior to traditional troubleshooting. Enabling SATCOM operators to install, configure, and monitor with extreme ease and confidence.

Control examples

Band switching, Gain offset, Alarm trigger, Persistent alarm, Alarm output, Temp ºC or F, GPO output, Modbus rtu parity mode

Monitor examples

Alarm, Persistent alarm, Selected band, IF out level, LNA current, Total current, Input voltage, Temperature, LO locked, ext. 10MHz detected, Ext 10MHz locked, Active ref (internal / 10MHz), 22kHz detect, Days of operation, Serial number, Software version


  • Monitoring & Control – function is enabled on select Products
  • Hardware – connecting host / RTU and M8 cable (RS-485) and/or USB Transceiver Learn more
  • Register Map – for available (R/W) parameters, please note that the Register Maps are specific to each product model. Download the latest Register Map in the Document section
  • Modbus software or driver is not included, for purposes of testing or troubleshooting there is a SMW Monitoring & Control (M&C) Evaluation Tool

Questions and Answers

Do I need one Modbus startkit for each LNB/BDC? 41C25639-EC1E-4330-A85F-624D51C798E8

No, you need only one startkit. The startkit is used for setup of devices such as changing client ID to different ID for each unit. Default client ID is “60” and can be changed between 1 and 247. After setting of different client IDs of more devices they can be connected together in a network for Monitoring and Control.

How to connect to the Monitoring and Control functions with a PC? 41C25639-EC1E-4330-A85F-624D51C798E8

The LNB or BDC must have the option installed and then it can be connected via the M8, 4-pin female connector. You also need a software or driver for Modbus RTU RS485 to be installed on the PC (host). There is two main ways to connect the PC to the LNB or BDC.
a) With a USB to serial RS485 transceiver between the PC and the LNB or BDC. The SMW startkit includes that kind of transceiver.
b) Via a Serial RS485 to Ethernet transceiver between the LAN port (RJ45 connector) on the PC and the LNB or BDC M8 connector.

How many devices can be connected to a Modbus network? 41C25639-EC1E-4330-A85F-624D51C798E8

The Modbus protocol allows for 247 devices on the bus (1 master + 247 clients). Further more the transceiver used in SMW products allows for 100 devices on the bus.

How to find a unit with unknown client ID? 41C25639-EC1E-4330-A85F-624D51C798E8

The SMW M&C Evaluation Tool has the possibility to scan ports and find devices client ID. Another way is to connect the device with unknown client ID to the host (PC). By using “0” (zero), broadcast mode, for the setting in Holding register (PDU address 0000) you will be able to write a new (unused) client ID to that device.

Connection to my PC does not work. What can be the problem? 41C25639-EC1E-4330-A85F-624D51C798E8

When connecting a USB to RS485 transceiver to a PC one must make sure that the serial port (USB/COM port) on the PC is correct chosen for that client. If connection to a device(s) is made via TCP/IP (LAN port), make sure that port 502 is chosen and that port 502 is open in the actual network (LAN). Also check that the IP address of the Serial to Ethernet transceiver is matching the IP settings in the PC. Your local network administrator may help you.

What is the default client ID? 41C25639-EC1E-4330-A85F-624D51C798E8

The default client ID is “60” and can be changed between 1 to 247. If you connect more devices (LNBs/BDCs) in same network, make sure that you first connect each device individually and change to different client IDs before installing in same network.

How do I start logging the Modbus parameters? 41C25639-EC1E-4330-A85F-624D51C798E8

You need a software or driver to log the data, which is not included, but for purposes of testing or troubleshooting there is a SMW Monitoring & Control (M&C) Evaluation Tool available on request.

Where do I find the Modbus register map? 41C25639-EC1E-4330-A85F-624D51C798E8

As there are specific Register Maps for each product, download the latest Register Map in the Document and Media section or on the specific product's webpage.

Band switching via Modbus is not working. Why? 41C25639-EC1E-4330-A85F-624D51C798E8

Check that Legacy control mode is set to “0” in Coils register (default is “1”, legacy mode i.e. voltage/22 kHz tone switching)

What is the limitations for the cables used? 41C25639-EC1E-4330-A85F-624D51C798E8

The limit is the cable length that is max 600 meter in total using shielded twisted pair cable minimum CAT5.

What is max current for the Alarm output pin 4 at the M8 connector? 41C25639-EC1E-4330-A85F-624D51C798E8

Up to 200mA 3.3V to 24 V can be used for as an example to connect to a relay.

The Alarm output at pin 4 in the M8 connector is not correct according to my connected device. How to change? 41C25639-EC1E-4330-A85F-624D51C798E8

In the Coils register, Alarm pin output config (PDU address 0000) you can change the output on pin 4 between NC and NO (Normally Closed or Normally Open). Default is NC.

How to check that the Alarm is activated? 41C25639-EC1E-4330-A85F-624D51C798E8

In the Holding register, Alarm triggers (PDU address 0001), the different alarms according to the Alarm map can be activated. Default is “decimal 255” i.e. all alarm triggers are activated. By writing “0” (zero) to that register, no alarms will be activated.
See the Alarm map for a specific product.

Is it possible to make individual settings for Alarm parameters? 41C25639-EC1E-4330-A85F-624D51C798E8

Yes, use applicable modbus software or driver to adapt the Alarm settings. For factory settings, please send an email to support@smw.se. For purposes of testing or troubleshooting is SMW Monitoring & Control (M&C) Evaluation Tool available on request.

How can I see if there is an Alarm or Sum Alarm? 41C25639-EC1E-4330-A85F-624D51C798E8

In the Discrete inputs register, Sum Alarm (PDU address 0000) you can read if there is an Alarm/Sum alarm or not. If value is “0” there is no alarm, if value is “1” there is one or more Alarms. What alarms that are active you find out in the Input register (PDU address 0000), and with help of the Alarm map for your product.

How does the Persistent alarm work? 41C25639-EC1E-4330-A85F-624D51C798E8

The Persistent alarm show if there has been any alarms since last reset of the Persistent alarm. Status of the Persistent alarm is shown in the Input register (PDU address 0001). If “0” there has not been any alarms since last reset. Any other values shows that there has been any kind of alarm(s) according to the Alarm map. Reset of the Persistent alarm is done in Coils register, Persistent alarm reset (PDU address 0005). Write “1” to clear the Persistent alarm.