DGH D2500 Sensor to Computer Interface Bridge Input Module

The D2500 bridge input module is part of the DGH’s D2000 sensor to computer interface data acquisition module family. This input module is an enhanced version of the D1500 module with added programmable functions. Similar to D1500 module, it converts the outputs from load cells, strain gauges or other bridge type sensor input signal to digital data, linearises and scales it in mV, and communicates the values using the ASCII protocol to give digital output. The D2500 bridge input module also contains a 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 and programmed features, meaning the values are maintained in the event of power loss. The D2500 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 D2500 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 bridge input module
• Additional programmable features – built-in commands to create custom input-to-output (nonlinear) transfer functions, with ASCII output scaled to desired engineering units and straight-line segment approximation of up to 24 segments
• Choice of RS-232 or RS-485 output
• Choice of ranges: 30mV, 100mV or 1-6Vdc
• Choice of excitation voltage: 5V(for bridges with input impedance ≥85Ω), 8V or 10Vdc (for bridges with input impedance ≥166Ω) @ 60mA maximum
• Communicates using ASCII protocol
• User-selectable features include baud rate, parity type and others
• Accuracy: ±0.05% or full scale maximum
• Resolution: 10μV for mV spans and 0.02% of full scale for V spans
• Common mode rejection: 100dB at 50/60Hz
• Input protection to 30Vdc
• Span temperature coefficient: ±50ppm/°C maximum
• Offset control: full input range
• Zero drift: ±1μV/°C maximum
• 1 Digital output (or LO alarm) as standard, this pin may be configured as digital input/events counter instead on request if preferred
• Power requirements: Serial = 0.75W
• Temperature range -25°C to +70°C

The applications for the D2500 data acquisition modules include:

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