44
Entek IRD 6666 and 6667 Protection Monitors
Testing Calibration and Relays
The 6667 thermocouple conditioning unit (terminal block) produces an output voltage range
of 0.4 volts to 4.8 volts for each of the thermoelectric voltage ranges in the table above. For
example, for suffix “B”, the thermocouple conditioning unit produces 0.4 volts at 0°C and
4.8 volts at 200°C. The maximum range for the monitor is 0–5 volts, which means that the
transducer failure values (“TX 1-3 and TX 4-6 submenus” on page 21) must be set inside
the 0–5 volt range. If you set the transducer failure values outside the 0–5 volt range, the
monitor can not detect a transducer failure.
This example assumes that the 6667 has a “C” configuration on channel 1.
Example:
Configuration type
“C”
Full scale low
0°C (0.000 mV)
Full scale high
150°C (6.137 mV)
TX LO
-5°C
TX HI
155°C
Note:
The sensitivity and full scale are set at the factory and cannot be changed. You can find
the sensitivity with the following equation.
For the “C” type configuration:
Refer to the following diagram for the correct connections between the monitor and the
testing equipment. This diagram shows the typical signal inputs and connections for testing
6667 monitors.
sensitivity
voltage high
voltage low
–
full scale high temperature
full scale low temperature
–
------------------------------------------------------------------------------------------------------------------------------------
=
sensitivity
6.137 mV
0.000 mV
–
150°C
0°C
–
------------------------------------------------------
0.0409 mV/°C
=
=
TYPIC AL SIGN AL INPUTS FOR TESTING
666 7 SIX CHA NNEL PROC ESS M ON ITOR
1 ( C H A N 1 S I G NA L I N P U T]
2 ( C H A N 1 S I G NA L CO M M O N )
+
-
V O L T A G E CA L I B R A T O R
O R T H E R M O C O UP L E
S I M U LA T O R
NO TE : T H E S E I NP UT S A R E
L O C A TE D O N T H E
TH E R M O C O U P L E C O ND I TI O N I NG
UN I T ( TE R M I N A L B LO C K )
