Quick Start Guide
4
Maintenance
4.1
General maintainence information
The sensors require mimimal maintenance.
Keep the sensor clean and free of debris or sediment at all times. The nature
of the solution measured determines the frequency of cleaning. To clean,
wipe with a soft cloth or brush with a brush. Remove the sensor from the
process periodically and check it in buffer solutions.
WARNING
Before removing the sensor, be absolutely certain that the process pressure
is reduced to 0 psig and the process temperature is lowered to a safe level.
4.2
Automatic temperature compensator
The temperature compensator element is a temperature sensitive resistor
and can be checked with an ohmeter. Resistance increases with
temperature.
PT-100 reads 110 ohms. Resistance varies with temperature and can be
determined according to
R
= R
[1 + R
T
O
Where R
Refer to
Table 4-1: R
Temperature element
PT-100
Table 4-2: Temperature vs. Resistance of Automatic Temperature
Compensation Elements
Temperature °F (°C)
32 (0)
50 (10)
68 (20)
77 (25)
86 (30)
40
Table 4-2
(T-20)]
1
= Resistance and T = Temperature in °C
T
Table 4-1
for R
and R
O
and R
Values for Temperature Compensation Elements
O
1
or the following formula:
values.
1
R
O
107.7
Resistance (Ohms) ±1% PT-100
100.0
103.8
107.7
109.6
111.5
November 2020
R
1
0.00385
Emerson.com/Rosemount