Datamax H Class Operator's Manual page 83

SENSOR
READINGS
RIBBON SENSOR
LIMITS
Displays the values (0 - 255, see sample below) read from different
sensors within the printer, where:
THR TRAN RIBM 24V
103 091
PS HD RANK
003 255
THR = Printhead thermistor sensor;
TRAN = Transmissive (gap) media sensor (TRAN is replaced with REFL
when the SENSOR TYPE is set to 'reflective');
RIBM = Ribbon sensor;
24V = 24 volt power supply sensor;
PS = Present sensor;
HD = Printhead position sensor; and,
RANK = Printhead ranking resistor.
Displays the values from the ribbon sensor readings (see example below)
for printers equipped with the thermal transfer option:
RIBBON ADC LOW
111
RIBBON ADC HIGH
249
009 171
050
75