• This gateway can read Modbus data from your Modbus RTU devices and publish it as SNMP data.
• It can also write to the Modbus RTU devices.
• This gateway can also do the reverse, read SNMP data and publish it as Modbus RTU data.
• It can also write to the SNMP devices.

In summary, this gateway can act as:

• Master on the Modbus RTU network: Hence it is capable of reading data from the various Modbus slave devices and writing data to them if required.
• Slave on the Modbus RTU network: You can use the gateway in this mode if you have a Modbus RTU master on the network which would be reading data from the gateway.
• Client/Master on the SNMP network: Hence it is capable of reading data from the various SNMP devices and writing data to them if required.
• Server/Slave on the SNMP network: The gateway can be configured to be a server of data values, hence another SNMP client can read data from the gateway and write data into the gateway.

Block Diagram:

• On a site you have several Schneider Ion energy meters that can provide data output on Modbus RTU.
• The site has a building management system on SNMP that needs the energy data from the Schneider ion meters.
• Since the Schneider ion meters provide data output on Modbus RTU and the Building management system understands only SNMP a direct data exchange is not possible.

Block Diagram:

Solution:

The devices can not directly communicate with each other as they are not on the same protocol. Modbus RTU is a Serial protocol, while SNMP is an Ethernet based Protocol. You need something that will convert data from SNMP device to Modbus RTU and vice versa.

ProtoConvert’s Modbus RTU to SNMP converter will be an excellent solution for this requirement. The gateway reads data from the Energy meters on Modbus RTU. It caches this data internally and then provides it on SNMP when requested from the Building Management system.

• On the other site we have PAC units that can provide data output on SNMP.
• The site has a PLC on Modbus RTU that needs the temperature data from PAC units on SNMP.
• Since the PAC units provide data output on SNMP and the PLC understands only Modbus RTU and a direct data exchange is not possible.

Block Diagram:

Solution:

The devices can not directly communicate with each other as they are not on the same protocol. Modbus RTU is a Serial protocol, while SNMP is an Ethernet based Protocol. You need something that will convert data from SNMP to Modbus RTU and vice versa.

ProtoConvert’s Modbus RTU to SNMP converter will be an excellent solution for this requirement. The gateway reads data from the Thermostats on SNMP. It caches this data internally and then provides it on Modbus RTU when requested from the PLC.

Modbus RTU:

ModbusRTU is a serial communication protocol that connects different devices on the same network and would make the communication between them possible.

Modbus is transmitted over serial lines between devices. The cables used for the connection are either RS-485 or RS-232 cables. The simplest setup would be a single serial cable connecting the serial ports on two devices, a Master and a Slave.

The data is sent as series of ones and zeroes called bits. Each bit is sent as a voltage. Zeroes are sent as positive voltages and ones as negative. The bits are sent very quickly. A typical transmission speed is 9600 baud (bits per second).

SNMP:

Simple Network Management Protocol (SNMP) was originally made for the management of devices such as switches and routers, its usage has grown so much nowadays that it is used for monitoring of nearly any electronic device one can think of.  It is a protocol which is majorly designed to manage networked devices from a single-central location. SNMP is now used to monitor and manage television broadcast studios, airborne military platforms, automated fare collection systems, emergency radio networks, energy distribution systems, and much more.  Microsoft Windows Server 2003 provides SNMP agent software that works with third-party SNMP management software to monitor the status of managed devices and applications.