Applications Guide
132
Modline 5
8.3.2
Determining Response Time to Use
The Response Time is factory set for the fastest response time allowed for its Model. You may wish to
select a slower response time that is more suitable for the process.
To follow temperature variations as they occur, select a fast response time. If you prefer to "filter out"
temperature variations, select a slower response time. In most applications, the practical approach is to
observe the temperature display or analog current output and adjust the response time for the most
meaningful temperature information without distracting variations. Observe the temperature
indications on a Temperature Display, or chart recorder.
illustrates the general effects of
response times as if plotted by a chart recorder.
The combination of low target temperature and fast response time will cause unstable
temperature indications. When measuring low target temperatures, adjust the
Response Time slowly to obtain stable temperature readings. Measurements below
400°F (200°C) may require a response time of one second or more. A Response Time
setting of 30 milliseconds usually provides good starting point for higher process
temperatures.
Figure 80: Effects of Response Time
Fast Response
Temperature
Tim
e
Medium Response
Temperature
Tim
e
Slow Response
Temperature
Tim
e
Temperature display and output
signals follow temperature
variations as fast as minimum
response time of instrument.
Rapid temperature variations are
“filtered out“ and system follows
general trends in temperature,
with small amounts of “ripple“.
Sensor tracks slow variations in
temperature ans effects of
temperature spikes are
eliminated.
