The External Trigger Cable can be used to remotely trigger a Micromate unit or to synchronize the triggering of up to six units. At the end of the External Trigger Cable there are two leads; a change in the state of these leads will cause the Micromate unit to start monitoring. They can be connected to start and once that connection is broken, the unit will start to record, or they can be separated initially and when they make a connection the Micromate will start to record. The External Trigger Cable connects to the auxiliary port (factory installed option) on the Micromate unit and comes complete with a 2 m (6.5 ft) cable. The External Trigger Cable can also be used with Instantel’s 100 ft or 250 ft extension cables.
- Twist the two leads together and use an energy source, such as a blast, to break the two leads apart, triggering the Micromate unit to start recording. Typically, the two leads are tied together and then wrapped around a detonator or explosive before being lowered into a borehole. When the explosives detonate, the two leads on the external trigger cable will break apart and automatically trigger the unit to start recording. This will give you time 0 or when the blast started. As each hole in the blast design is detonated it will create a peak in the waveform. Using time 0, you can calculate the time between each peak and compare it to the time delays between each hole and row in your blast design. You can then use this data to help you design a more controlled and precise blast.
- Velocity propagation of the rock is a key part of blast design. Using the External Wire Trigger Cable you can measure accurate velocity propagation values from the rock you are blasting. The External Wire Trigger Cable can be used to synchronize event recordings on up to six monitoring units. After connecting an External Trigger Cable to each unit and tying their leads together, when one Micromate unit is triggered and begins recording, the other connected Micromate units will also begin to record. The time it takes for the vibration to travel from one Micromate unit to the next can be used to get an accurate velocity propagation value.