Inputs and Outputs
The basic input/output capabilities of the Etherlog 3000 are:- eight 18-bit plus sign analogue inputs
- eight opto-isolated digital inputs
- four digital outputs
The illustration shows the Etherlog as supplied as a data acquisition module,
with the front-end card mounted above the RDL3000 circuit card.
The versatile front-end card provides high-quality screw-down connectors to permit easy connection of sensors and other circuitry to all analogue and digital channels.
An analogue patch header allows inputs to be terminated as required, and DIL switches can be set to pull up curve-matched 10k thermistors to Vref via 10k precision resistors, for simple and convenient temperature measurement.
Analogue inputs
- instrumentation quality 18 bit plus sign analogue to digital converter
- differential inputs with ±512mV sensitivity and 35V over-voltage protection
- switched and buffered 512mV reference voltage output for ratiometric readings
- measurements integrated over one mains cycle to reject interference
Digital inputs
- opto-isolated input lines for maximum protection
- suitable for event monitoring or triggering conditional measurements
- two inputs can operate as low speed counters in low power operation
- all inputs can act as pulse counters in applications where power consumption is unimportant
Digital outputs
- 30V 100mA open-drain MOSFET outputs
- can be used to control external equipment
- raise a local alarm based on measurements or an incoming radio message
- power up sensors and/or additional signal conditioning circuitry prior to reading
- control GSM modem power supply to conserve power when not required
Input expansion using RDT 3000 telemetry modules
The input capabilities of the Etherlog can be extended by configuring up to eight
RDT 3000 modules. Each RDT 3000 has:
- eight 12 bit unipolar analogue inputs
- four digital inputs
- four pulse counters triggered by the digital inputs