Rockwell Automation 1771-IXE/D Thermocouple/Millivolt Input Module User Manual - Manual (Page 72)

Differences Between Series A, Series B, Series C and Series D Thermocouple/Millivolt E–2
Publication 1771-6.5.130 Ć May 1999
Explanation of Differences
•
Calibration is now done automatically using auto–calibration
feature, or manually through programming.
•
calibration is now done at 0.000mV and +100.000mV .
•
If EEPROM read of the auto cal values fails, BTR WORD 1 bit 7
is asserted.
•
Series A used potentiometers for calibration settings with
calibration done at –99 and +99mV.
•
RTS can now be reduced to 100ms for all thermocouples by
programming RTS = 1.
•
The default RTS setting (RTS = 0) makes data available every
50ms. Series A default value was 500ms.
•
BTR WORD 12 is the rounded Cold Junction Temperature
resolute to 1 degree C displayable in the programmed format
(BCD, 2s complement or signed magnitude). In Series A, BTR
word 12 was the cold junction calibration word.
•
BTW WORD 1 bit 7 is no longer used (cold junction
update).
•
Cold Junction calibration by the user is no longer required; it is
calibrated at power up.
•
Cold junction temperature is digitally filtered having a filter
time constant of 12.8 seconds. It is no longer updated once per 15
second interval.
•
Cold junction value is updated continously in Series B. Update
was once every 15 seconds in Series A.
•
Backplane power is approximately 750mA at 5V. Series A had a
backplane power requirement of 1200mA.