Nomis Mini SuperGraph – Quick Guide

(Blast Monitoring Mode)

Overview

The mini SuperGraph is a very advanced ground vibration monitor from Nomis and follows on from the highly successful NS5400. The mini SuperGraph enables ground-borne vibration and air over-pressure to be monitored with ease. Just two button presses after switch on is all that is required to begin a monitoring session.

The instrument stores recorded data in memory and there is no wait-time between events. Up to 300 two second events may be stored.

The instrument has the ability to store user and location information so that several users may use the instrument with their parameters (location data, distance to vibration source, etc). This saves operator time and the inconvenience of having to repeatedly alter the set-up for different users and/or locations.

A single auto-scaling range of 0.1mm/s to 254mm/s means no more over-range errors.
The air over-pressure range is from 90 to 148dB(Linear Peak).

Set Up

Connect* and position the tri-axial geophone sensor unit** and the air over-pressure microphone, before switching the instrument on. The instrument will show its main menu with four items. The first item, self-trigger will be highlighted.

If the user set-up is correct, i.e. the user wishes to use the existing settings, press enter and Waveform Mode is displayed together with two items. The first item is Monitor and the second is Edit. Press Enter to begin monitoring.

On completion of the monitoring session, press Escape and press Enter. Then hold down the Off button for 2 seconds.

Clean and dry all accessories before storing them in their compartments.

Notes:

1. Charge the battery for twenty-four hours every two weeks, whether the instrument is used or not.
2. Using Edit mode is self explanatory and enables user, location, distance to source, maximum charge weight, trigger level and event time information so that several users may use the instrument with their parameters. Navigation is by way of the UP and Down arrow buttons, Plus and Minus buttons (for Date & Time) and the Enter button.

* If the sensor is connected after switching on, all readings will be invalid.

Edit Mode

In edit mode characters are entered using the up & down arrows. The cursor is moved forwards & backwards using the + & - keys. A useful default for UK quarries is:

Sample rate: 1024
Company: The Company name may be entered
Seismograph Location; The location name may be entered
Notes: A place to record any other information that may be useful
Distance to Source: The distance between the source and the monitor may be entered
Weight per Delay: The Maximum Instantaneous Charge (MIC) may be entered
Operator: The operators name may be entered
Seismic Trigger: 0.5mm/s
Sound Trigger: N
Record Time: 3 Seconds (options are between 1 and 80 seconds)

After input of the required parameters, the option to save is shown. A name for the set-up will allow these parameters to be used again, when the named set-up is chosen.

To use the pre-set settings, after switch-on in the main menu of four items, select option 4 by using the down arrow button to Saved Settings and press Enter, then highlight the desired set-up by using the arrow buttons and press Enter.

Using the Help Menu

After switch-on press Help
Only the first option is currently enabled, press Enter.
To navigate through the options use the arrow buttons and the Plus and Minus buttons to change the time and date. Press the Enter button to select an option, and Escape to return to the menu. The choices here are self explanatory.

Events in memory may be previewed on the LCD via the Help menu; Summaries Events.

A sleep function (Timer Mode) is available through the Help menu allowing the instrument to begin monitoring at a pre-determined time; each day, once a week or once a month. A useful option, when the instrument is used for long-term unattended monitoring, to prevent excessive amounts of data caused by spurious triggering of non-blast induced events.

** Placing the tri-axial geophone sensor unit

One of the most critical aspects of vibration monitoring is the placement and coupling of the measurement transducer. The accuracy of reading is only as good as the quality of the connection between the transducer and the ground surface. This connection, known as coupling, is vitally important in obtaining valid results. When Peak Particle Velocities are greater than 10mm/s the transducer should be buried completely, when the measurement surface consists of soil. A sandbag can also be effective if used properly, being loosely packed and large enough so that, when placed on the sensor, all sides of the bag are resting firmly on the ground surface. When measuring on a firm surface, attachment can also be by means of epoxy resin or bolting. The mini SuperGraph is supplied with three ground-spikes to enable easy coupling of the sensor when ground conditions allow their use. The sensor must be used only in a horizontal orientation with the arrow pointed towards the vibration source.