The D1400M RTD input module is part of the DGH’s D1000M Modbus sensor to computer interface data acquisition module family. This input module converts the RTD temperature sensor input signal from the choice of three different RTD types (0.00385, 0.00388 and 0.00392) to digital data, linearizes and scales it in °C or °F, and communicates the values using the Modbus RTU protocol to give digital output. The D1400M RTD input module also contains one open-collector digital output 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 Modbus RTU command can be used to setup desired baud rate, parity and other parameters. The D1400M 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 RTD input module
• Choice of RS-232 or RS-485 output
• Choice of 3 different RTD types: 0.00385, 0.00388 or 0.00392
• Communicates using Modbus RTU protocol
• User-selectable features include °C or °F, baud rate, parity type, channel address and others
• Accuracy: ±0.3°C maximum
• Resolution: ±0.1°(C or F)
• Common mode rejection: 100dB at 50/60Hz
• Autozero and auto-calibration
• Up to 246 multidrop modules per host serial port (RS-485 only)
• 2, 3 or 4 wire input connections
• Maximum lead resistance of 50Ω
• Excitation current of 0.25mA
• Input burnout protection to 120Vac
• Lead resistance effect of 2.5°C per Ω of imbalance for 3-wire option, negligible for 4-wire option.
• Automatic linearisation and lead compensation
• 1 open-collector digital output
• Power requirements: Serial = 0.75W
• Temperature range -25°C to +70°C

The applications for the D1400 data acquisition modules include:

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