FAHM HART PTT74-E Series, Руководство пользователя

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SMART Temperature Transmitter
PTT74-Ex Series User Manual
Sep.2020
22
www.faraboard .com
FAHM Co .
Industrial Automation
Doc. PTT74-ExRev99/07M
3.2.7.2 Cold Junction
PTT74-Ex series temperature transmitters has an internal temperature sensor to calculate
the actual temperature of input terminals. This sensor can be used as cold-junction
temperature in thermocouple applications.
User can configure the cold junction related parameters using below menu:
parameter display Parameter tuning structure
Cold-Junction
Mode
(Cold-junction
temperature
calculating method)
Press <M> until this page is appeared on LCD. Then press
<Z> to access the Cold-Junction Mode (programing
mode). You can select the mode by pressing <S>. After
that, press <Z> until all characters blink. Then press <M>
for the saving new parameter and switching from
programing mode to operation mode.
Cold-Junction
Value
(fixed Cold junction
value)
Press <M> until this page is appeared on LCD. Then press
<Z> to access the amount of Cold-Junction Value
(programing mode). You can change the amount of
digits by <S> and change the point and position of digits
by <Z>. After tuning this parameter, press the <Z> until
all characters blink. Then press <M> for the saving new
parameter and switching from programing mode to
operation mode.
The available Cold-Junction modes are as follows:
NONE [cold junction temperature compensation is not required]
EXT [a fixed value will be used as cold-junction temperature]
INT [the internal temperature sensor will be used as cold-junction temperature]
This variable is visible when the sensor type of temperature sensor element was selected as
thermocouple. In this situation user can select the method of calculating of col-junction
temperature. In other situation “No cold-junction” will be selected automatically by device.
In thermocouple application if the cold-junction leads of thermocouple be wired to input
terminal of device directly, user should select the internal compensation method. But if the
cold-junction lead of thermocouple be wired to a fixed temperature junction box and be
wired to input terminals using general wires, user should select external temperature
method and determine the junction box temperature as cold-junction value.