The D1500M bridge input module is part of the DGH’s D1000M Modbus sensor to computer interface data acquisition module family. This input module 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 Modbus RTU protocol to give digital output. The D1500M bridge input module also contains a 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. These 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 baud rate, parity and other parameters. The D1500M 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 bridge input module
• 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 Modbus RTU protocol
• User-selectable features include baud rate, parity type, channel address 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
• Autozero and auto-calibration
• Up to 246 multidrop modules per host serial port (RS-485 only)
• Input protection to 30Vdc
• Span temperature coefficient: ±50ppm/°C maximum
• Offset control: full input range
• Zero drift: ±1μV/°C maximum
• 1 Digital output open collector to 30V, 30mA maximum load
• Power requirements: Serial = 0.75W
• Temperature range -25°C to +70°C

The applications for the D1500 data acquisition modules include:

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