Hey, I hope this is what you want.
on place of oak pressure plate:
set {pressureplateloc} to location of event-block
send "&e&lLOCATION &7| &6Location set" to player
on pressure plate:
if {pressureplateloc} is set:
give player 1 diamond
send "&c&lHey&7, you've got 1 diamond!" to player
on break of oak pressure plate:
delete {pressureplateloc}
send "&e&lLOCATION &7| &6Location unset" to player