The D1400 RTD input module is part of the DGH’s D1000 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, linearises and scales it in °C or °F, and communicates the values using the ASCII protocol to give digital output. The D1400 RTD input module also contains one open-collector digital output (or LO alarm) 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 D1400 comes pre-set with default values of 300 baud, one start bit, eight data bits, one stop bit, no parity and any address recognized, but these values can be easily changed by the user. 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. The D1400 can be mounted on a DIN-rail if required (MK-1 mounting kit required) and can be combined with other D1000/D2000 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 ASCII protocol
• User-selectable features include °C or °F, baud rate, parity type and others
• Accuracy: ±0.3°C maximum
• Resolution: ±0.1°(C or F)
• Common mode rejection: 100dB at 50/60Hz
• 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:

• Process monitoring and control
• Remote data logging to any host computer
• Product testing
• Direct connection to modems