Specifications
21
SLC 500 Programmable Controllers and I/O Modules
Temperature
Modules
Greatly enhance the temperature
monitoring and control capabilities of
your SLC 500 system with the 1746
temperature modules. Temperature
modules eliminate the need for
expensive thermocouple transmitters,
providing a more economical means of
addressing process applications in
industries requiring temperature
measurement and control.
1746-NT4, 1746-NT8, 1746-INT4
Thermocouple/mV Modules
Features
• 1746-NT4 and -NT8 modules provide a choice of four filter frequencies, permitting
you to select input noise filtering appropriate to the application and surrounding
environment. Either or both 50 Hz and 60 Hz noise can be filtered from the input
signal for greater noise rejection and resolution. The 250 Hz filter provides
minimum noise rejection and is best suited for mV input applications where
fast response to step changes is required.
• All modules provide cold-junction temperature compensation (CJC), fully
integrated into the removable terminal block, as a means of retaining
thermocouple input signal accuracy. Two thermistor assemblies located
at each end of the terminal block measure and compensate for the absolute
temperature of the reference junction.
• 1746-NT4 and -NT8 provide auto-calibration functions to compensate for module
component drift. This guarantees module accuracy and saves valuable time.
• All modules provide fault diagnostics to check for open circuits or out-of-range
values, then indicates operational problems on status LEDs. Four channel status
LEDs and diagnostic bits signal you if input channel data is out of range or if an
open-circuit condition is present. Channel configuration validity is also checked.
In addition, a module status LED differentiates recoverable channel errors from
more serious module-related problems, saving you troubleshooting time.
• The high-density 1746-NT8 module is ideal for applications with a large
number of thermocouple inputs.
• The 1746-INT4 module provides 1000V peak channel-to-channel isolation
(150V ac continuous).