(openPR) - TMO-100, Radio modem for data communication in Tetra infrastructures

Different applications, and different geographical regions, have different requirements for automation protocols. Energy utilities in Germany and Europe use common standards (IEC 60870-5-101 or IEC 60870-5-104). In Asia and the U.S. they generally use the Modbus RTU or DNP3 protocol. Less well known is the PakBus Sinaut protocol from Siemens, which is primarily used in the water and sanitation industries.

The Modbus RTU Protocol is particularly good for slow or wireless transmission paths, due to its user-friendly and solid structure. However, compared to other protocols, the Modbus RTU Protocol has the disadvantage that the outstation exclusively works by polling, which is the cyclical polling of each individual station by the master station. Other protocols have the advantage of the outstations using event-driven messages, rather than waiting to be polled by the master. Through this process, alarms can be reported independently from the polling cycle of the Master device.

The TETRA TMO-100 supports pro¬tocols such as Modbus, PakBus, the Sinaut protocol from Siemens and many more. The TMO-100 does not generally (but can if required) work with GISSI, but each single data set will be sent to the one outstation it is addressed to. This is a major benefit of TETRA infrastructures, due to the high network load when sending group messages, rather than selective messages. Another feature that reduces the network load is the integrated modified LZ77 data compression mechanism.

For the Modbus RTU Protocol the TMO-100 offers a special option to make it possible to process event-driven alarms on a spontaneous basis. For this the outstations can be ordered with an optional E/A Board in addition to their serial interfaces. These inputs can be used to automatically send status alarm messages to the master station. This master station stores the alarms in Modbus registers, where they can be accessed at any time though the connected master-PLC or the SCADA Server. This makes it possible to react to alarms or malfunction messages at any time, in the same way as unsolicited messages.

In addition to the serial asynchronous protocols, the TMO-100 can also process UDP- and TCP-protocols. In this case, the device operates as a TETRA router.
After the device is turned on, a PPP-connection is automatically established to the Tetra infrastructure, and the unit receives an IP-Network address from the Tetra Switch. The TMO-100 immediately send IP data from the local Ethernet interface to the TETRA-IP-world, and vice versa. For this the TMO-100 uses NAT, Port Forwarding and Port Translation, which turns the device into a fully-featured TETRA-router. For the user connected on the local IP-Port, the Tetra infrastructure is not actually visible. He simply connects the PLC to the Ethernet port and, after setting up the IP-Address, will be able to communicate with other devices or the SCADA Server within the TETRA infrastructure (and also, if enabled, beyond that).
The device can be configured either via the embedded Web server, the Modbus RTU Protocol using its serial interface, or the Modbus/TCP via its local Ethernet interface, or remotely via the TETRA infrastructure.

For applications that need embedded digital or analogue inputs and outputs (I/O) within the device, the TMO-100 can also be delivered with an optional I/O-board with 16 digital inputs, 8 (optional 16) digital outputs, and 4 analog inputs (12 Bit resolution, 0-20mA/4-20mA). As well as the 16 binary inputs, the device is equipped with 8 event counters and 8 timer counters. All inputs and outputs are isolated. Access to the inputs and outputs takes place via the Modbus-RTU or the Modbus/TCP Protocol, and can be realized locally or via the TETRA infrastructure, using either SDS or Packet Data.

Another important characteristic for data modems is the ability to set up a voice connection. Using an eight-pole RJ45 plug, an RSM (remote speaker microphone handset) can be attached to the TMO-100. When the PTT (push to talk) button on the RSM is pressed, the modem disconnects all data connections (SDS, CSD, PSD) and automatically switches into voice mode. A voice call is set up to either a preset ISSI or GSSI. After finishing the conversation, the data communication will automatically be restarted by the device. When switching from voice mode to data mode or vice versa, the modem can still send a status message to the control center.

Since 25 years the company is successful in producing and distributing radio telecontrol, especially radio and radio-modem solutions for data transmission.Since 1996 Funk-Electronic Piciorgros GmbH has focused on automatization, water and waste water control for electricity and utility companies and the industry in general.

Funk-Electronic Piciorgros GmbH
Claudiastr. 5
51149 Cologne-Porz, Germany

Tel. +49 2203/ 911 770
www.tetramodem.com