SubscribeLee-Dickens Sitewatch MIDI Remote Terminal Units are intelligent microprocessor based devices for monitoring and controlling equipment at remote sites.
The MIDI 8 uses the same distinctive IP65 rated moulded enclosure as the previous model, but the use of the latest compact surface mount technology and RoSH components has freed up space for a number of additional features. These features include a broad range of interchangeable networking communication options including PSTN (fixed line modem), GSM and LAN Ethernet communications.
The unit also has a transient to transmitter logic (TTL) interface that enables off the shelf modems to be used. This means a GSM or Ethernet modem can be easily swapped should it fail or the communications method need to be changed. The modems and radio transceivers are powered from the RTU itself and supported by standby batteries should mains power fail.
As well as increased networking options, additional I/O has been added. The Sitewatch MIDI 8 has 8 optically isolated digital inputs, 8 differentially selected analogue inputs and a further 3 digital outputs fitted as standard.
The digital input capacity can be increased to 16 or 4 pulse inputs can be added by fitting a small expansion board.
Digital and analogue inputs are configured by on-board links to provide a two wire interconnection to site equipment. A 24 VDC 250mA supply is available to power external analogue transducers.
Each Sitewatch MIDI 8 has two serial data ports, one of which is configured for the Master Station communications interface and a second that can be used for local interrogation, connection to other RTU's via a Local Area Network or for interfacing to other intelligent site equipment.
All field connections are made to plug-in screw terminals on the input/output board. A four line by 20 character LCD and 16 key keypad can be fitted for local operator display and interrogation.
The channel names to be displayed in the RTU can be specified by the user and can therefore be in any language to suit the operator.
The Sitewatch MIDI 8 has a built in data logging facility for all inputs and outputs and a real time clock used to time and date stamp the logs. The baseline operational software (boot software) is held in non-volatile EPROM memory with application programs and critical site configuration data held in Flash ROM.
Logged data is held in battery backed CMOS static RAM.
