NX21
Self Contained wireless telemetry device for use with analogue and digital sensors
- 12 digital inputs
- 2 analogue inputs
- Battery powered - no supply needed
- GPRS Communications (with GSM option)
- Built in Temperature Sensor and Signal Strength Meter
- Wall mounted IP54 enclosure
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Overview
With 12 digital inputs and 2 analogue inputs the NX21 is ideally suited to a range of monitoring applications. For sites where there is no external power available the NX21 can provide power for itself and external 18V dc analogue sensors.
Digital Inputs
Accepting Volt-Free (dry) contacts. The whetting current is provided by the RTU. Each input can monitor rising and/or falling edge. Minimum detection time is 10ms. When a change of state event occurs the following actions are taken:
- Date/time stamped record placed in event log
- Call initiated to the Host (optional)
Analogue Inputs
Accepts 4-20mA contacts. Each of the 8 analogue inputs is measured using 8-bit resolution and can be configured locally or remotely with 4 threshold levels. When a level is crossed the following actions are taken:
- Date/time and level stamped record placed in event log
- Call initiated to the Host (optionally)
The interval between reading the analogues is configurable in order to balance the need for data and the need for extending the battery life.
Analogue Datalogging
Each analogue input can be configured to record values at routine intervals. These values are date and time stamped and stored in non-volatile memory. The interval between samples and the time needed to stabilise readings are configurable settings.
Powering 4-20mA transducers
External sensors can be provided with power directly from the RTU. This is used where there is no external power supply available for the sensors.
The power to the sensors is switched on/off in synchronisation with the reading of the RTU analogue inputs.
Temperature Logging
The RTU has an on board temperature sensor. The temperature of the RTU is reported to the Host during every contact.
Battery Pack
The self contained battery pack provides power for up to 10 years of continuous operation. When analogue inputs are being utilised and when the RTU battery is being used to provide power to external sensors the life of the battery is reduced - contact Nortech for more details.
GSM or GPRS option
The RTU can be user configured to use either GSM (Circuit Switched Data service) or GPRS (General Packet Radio System) connections to the Host. Nortech can advise on which one will be best for your application.
Communications with iHost
RTU reports alarms, routine status and other collected information to a Central Nortech Host Terminal. This can be the Nortech i-Host System which makes the information available to users via a secure website or for larger systems it can be installed at customers own control rooms. Call duration will typically be in the region of 10 - 40 seconds depending on the volume of data to download.