The D1200M current input module is part of the DGH’s D1000M Modbus sensor to computer interface data acquisition module family. This input module converts current input signal from the choice of five different current ranges (±10mA, ±1mA, ±100mA, ±1A, and 4-20mA) and continuously converts the data using the Modbus RTU protocol to give digital output at the rate of 8 conversions per second, storing the latest data in the buffer. The data can be retrieved by sending an Modbus RTU command from the host computer. The D1200M current input module also contains one digital input and two open-collector digital outputs which may be controlled by the host computer and used to control, for example, solid-state relays. For extra security, it utilises a non-volatile EEPROM (Electrically Erasable Programmable Read Only Memory) to store all user-selectable settings, meaning the values are maintained in the event of power loss. The modules are designed to be compatible with all popular computers utilising RS-232C or RS-485 ports and no software is necessary to start using them, although the utility software is provided. Upon startup, a simple command can be used to setup desired baus rate, parity type and other parameters. The D1200M can be mounted on a DIN-rail if required (MK-1 mounting kit required) and can be combined with other D1000M/D2000M modules to provide complete customised data acquisition system for given application.

• Analog-to-digital current input module
• Choice of RS-232 or RS-485 output
• Choice of 5 different ranges: ±10mA, ±1mA, ±100mA, ±1A, and 4-20mA
• Communicates using Modbus RTU protocol
• User-selectable features include analog input range, baud rate, parity type, channel address and others
• Accuracy: ±0.02% of full scale, 0.04% of full scale for 4-20mA models
• Resolution: 0.01% of full scale (4 digits) or 0.04% of full scale (4-20mA)
• Span temperature coefficient: ±50ppm/°C maximum (±80ppm/°C for ±1A option)
• Autozero and auto-calibration
• Up to 246 multidrop modules per host serial port (RS-485 only)
• Common mode rejection of 100db at 50/60Hz
• Zero drift: ±1 count maximum (autozero)
• 1 Digital input with ±30V Voltage levels, switching levels of 3.5V minimum, low, 1.0V maximum and internal pull up resistors for direct switch input
• 2 Digital outputs, open collector to 30V, 30mA maximum load
• Power requirements: Serial = 0.75W
• Temperature range -25°C to +70°C

The applications for the D1200M data acquisition modules include:

• SCADA
• Data monitoring
• Data loggers
• PLC’s
• Process controllers and instrumentation