pan_low_limit = int(self.send_query("PN", 2))
pan_high_limit = int(self.send_query("PX", 2))
tilt_low_limit = int(self.send_query("TN", 2))
tilt_high_limit = int(self.send_query("TX", 2))

limits = [(pan_low_limit, "PN"), (pan_high_limit, "PX"), (tilt_low_limit, "TN"), (tilt_high_limit, "TX")]
for v, c in limits:
    v = int(self.send_query(c, 2))
    print("Result from {}: {}".format(c, v))
print(limits)
print("tilt_low_limit: {}".format(tilt_low_limit))

Result from PN: -27067
Result from PX: 27067
Result from TN: -27999
Result from TX: 9333
[(1, 'PN'), (1, 'PX'), (1, 'TN'), (1,'TX')]
tilt_low_limit: 1
PN: 1