The D5450M thermistor input module is part of the DGH’s D5000M low cost multichannel MODBUS data acquisition module family. This module features four channels, each accepting thermistor input signal from thermistor type 2252Ω at 25°C. The signal is converted to digital data at the rate of 8 conversions per second, then to engineering units using the lookup tables, storing the latest data in the buffer. The data can be retrieved by sending an appropriate command from the host computer. 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 D5450M 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-232 or RS-485 port and no software is necessary to start using them, although the utility software is provided. The D5450M can be mounted on a DIN-rail if required (MK-1 mounting kit required) and can be combined with other D5000 series modules to build a low cost data logger or a data acquisition system for given application.

• 4 channel analog-to-digital thermistor input module
• Choice of RS-232 or RS-485 output
• Input: 2252Ω at 25°C type thermistor
• Range: 0°C to 100°C
• Communicates using DGH ASCII or MODBUS RTU protocol
• User-selectable features include °C or °F, analog input range, baud rate, parity type and others
• Accuracy: ±0.1°C
• Resolution: 0.01°C (or °F)
• Input protection to 30Vdc
• RS-232 versions are limited to one ADC per serial port (due to MODBUS RTU not supporting echoing)
• Power requirements: Serial = 0.75W
• Temperature range -25°C to +70°C

The applications for the D5450M data acquisition modules include:

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