Rockwell Automation 1734-IT2I Thermocouple and RTD Input Module User Manual - Manual (Page 16)

Publication 1734-UM004F-EN-E - December 2012
6 About POINT I/O Modules
• Low-Low
• High
• High-High
When the channel input goes below a low alarm or above a high alarm, a bit is
set in the data table. All Alarm Status bits can be read individually or by
reading the Channel Status Byte (Bits 2...5 for channel 0; bits 10...13 for
channel 1).
You can configure each channel alarm individually.
Open-wire Alarm (1734-IT2I, 1734-IR2, and 1734-IR2E modules)
The module has the ability to check for a broken or detached wire. In any
mode, if a broken/detached lead is detected, the data value is forced to
maximum and the overrange alarm is set. Once the alarm is issued, it remains
active as long as the input signal is faulted.
Cold Junction
Compensation
(1734-IT2I module) When using thermocouples, cold junction compensation is required at the
termination of the thermocouple wire. Accomplish a cold junction in the
following ways:
• Enter an estimated temperature.
• Use a 1734-TBCJC mounting base (recommended).
• Use external cold junction compensators.
Entering an estimated temperature is the least accurate way for CJC
compensation. Using the compensation built-into the 1734-TBCJC provides
the easiest and most accurate way.
An open CJC causes the CJC input to point to the maximum temperature
value for the selected input type. This causes an alarm to be set. Once the
alarm is issued, it remains active as long as the input signal is faulted (above
maximum).
Chapter Summary In this chapter you were given an overview of the 1734 family of modules. The
next chapter walks you through installing your module.