Understanding the BlastPED
Security Access Disk
Each BlastPED receiver is supplied with a floppy disk containing codes of the ARM and BLAST commands for this particular unit. Without the disk, the PEDCALL operator will not be able to transmit commands to the BlastPED. The disk therefore should be kept in a secure location.
Safety Key
The output terminals are short-circuited while the safety key is in the SAFE position. The safety key can only be removed while in the safe position.
Firing Output
BlastPED is a capacitor type exploder suitable for series firing. The output capacity of the BlastPED is rated up to 75 Ohm series circuit (with the 2.1 safety factor applied, as per Australian Standards, means the unit is actually capable of firing a 160 ohm circuit).
BlastPED is to be used for firing simple series circuits only.
Series-in-parallel or parallel-in-series circuits are not to be fired using BlastPED. The output terminals can accept cables up to a maximum of 4 mm diameter.
BlastPED can is fitted with an Ohmmeter which automatically performs a firing line resistance test when the unit is turned on. Normal readout will not be over 75 Ohms.
If the reading is over this value of resistance, check the circuit to determine the cause.
When the safety key is in ON position the BlastPED has the output short-circuited. The short circuit is not removed until the ARM command is received by the unit.
The electrical energy necessary to initiate the detonators is made available from internal capacitors. These capacitors are short circuited until the ARM command is received, when they will then commence charging.
After blasting the short circuit is automatically applied across output terminals by internal relay contacts.