EUROTHERM has released the MMTCP16DI, a Modbus TCPIP slave interface that allows up to 16 digital inputs to be monitored, with the information directly accessible to users over any existing Ethernet network.
The inputs are isolated from the logic by bidirectional optocouplers. The inputs are divided into two isolated groups of eight inputs each. This allows for many configurations in which the input module may be used.
The counters operate in three modes. The counters can be disabled and the input used as a standard digital monitoring input. In mode 1 the first eight inputs have internal counters associated with them. These are 32-bit counters, allowing a count value from 0 to 4,294,967,295. The count value can be cleared by writing a zero to the associated registers or preset to any other value using the same method.
In mode 2 the inputs are connected as up/down counters. Input 1 will increment counter 1 whilst input 2 decrements counter 1. In the same way, inputs 3 and 4 operate counter 2, inputs 5 and 6 operate counter 3, and inputs 7 and 8 operate counter 4.
The format of the registers allows the status of the inputs to be read as single bits or all at once as a single register on the Modbus network. The MMTCP16DI communicates using the standard Modbus/TCP protocol. The converter supports four TCP sockets. This means that up to four devices can communicate with the serial communication modules via the converter at any one time. This eliminates problems associated with multiple master communication conflicts which occur on a serial network.
Each MMTCP16DI has a unique Ethernet IP address which must be programmed into the PC or PLC. The IP address in the converter is configured via the Web server. Any standard Web browser can be used to access the web pages where configuration is carried out. The converters are factory programmed with a default IP address, which can be changed before the converter is added to an existing network.