Convention:
0 is the OUT limit switch
-500 is the OUT position in EPICS controls
-500 is the High (soft) Limit
Low (soft) limits are probably -40000 or -70000 or there abouts depending on the actuator. There are IN limit switches installed.
All values should be -ve. Some actuators are about 50 mm travel and some are about 100 mm travel. The long and the short is that if you are going lower than -50 mm and you haven't seen a target, there is probably something wrong.