KROHNE OPTITEMP TCA Ex EN - Manual (Page 23)

INSTALLATION
3
23
OPTITEMP TRA/TCA
www.krohne.com 10/2010 - 4001087001 - Ex AD OPTITEMP TRA/TCA R02 en
Step 2: Calculate the maximum permitted temperature at the process connection
• You must always calculate the highest permitted temperature at the process connection for
temperature classes T5 and T6 ( refer to Temperature at process connection (with
temperature transmitter, classes T5 and T6) on page 17); therefore go directly to the specified
subchapter and omit the following steps.
• For all temperature classes except T5 and T6 refer to the tables with the maximum permitted
temperatures at the process connection; these also differentiate between thermometers with
and without a temperature transmitter ( refer to
Temperature at process connection (without
temperature transmitter) on page 13, refer to Temperature at process connection (with
temperature transmitter) on page 15).
• Find the model of thermometer used with the right neck pipe length in the first column of the
table (in this case: TxA-F13, neck pipe ≥ 80 mm / 3.15").
• Keep going to the right until you reach the column with the right ambient temperature T
a
(in
this case: 40°C / 104°F).
i The maximum permitted temperature at the process connection is T
P
= 400°C / 752°F.
Step 3: Calculate the maximum permitted temperature at the process connection with
a thermometer connecting cable
• Refer to the table with the maximum permitted temperatures at the process connection with a
thermometer connecting cable refer to Temperature at process connection for
thermometers with connecting cable on page 18).
• Calculate the maximum permitted temperature as explained above ("step 2").
i The maximum permitted temperature at the process connection for a thermometer with
connecting cable is T
P
= 364°C / 687°F.
In this example the selected industrial thermometer is suitable for the specified process
conditions having checked all the maximum permitted temperatures. It falls into temperature
class T4.
.book Page 23 Friday, November 19, 2010 2:23 PM