820/821 Series Digital Temperature
Indicators User Manual
1. Description
The NOSHOK 820/821 Series Digital Temperature
Indicators are a complete solution for most industrial
temperature monitoring and temperature indicating
applications. Made with high quality construction, these
gauges features a bright and large 4-digit red LED
display with an analog 4-20mA output. They are
designed for optimum
820/821 Series are an ideal replacement for bi-metal,
liquid bulb and gas thermometers. They are also a
suitable replacement for Mercury reduction programs.
The 820/821 Series can be factory calibrated to a
customer specified temperature range. The 820/821
Series' built-in programmable transmitter can be rescaled and re-calibrated using the optional interface
module and software.
accuracy and performance. The
The 820/821 Series Digital Temperature Indicator
arrives factory scaled and calibrated to the customer’s
specified temperature range. No costly field calibration
is required. If the application changes, the 820/821
Series can be re-scaled at any range within the sensor
limits while maintaining its accuracy.
The housing, probe and fitting material is all fabricated
from stainless steel 316. The 820/821 Series
Temperature Indicator is rated to NEMA 4X ( IP65 ).
Multiple mounting configurations are available to meet
customer requirements.
Standard extension cables offered are PVC or Silicon
insulated wires. Some models are available with M12
Micro-Male Connector.
2. Function
The 820/821 Series line of temperature indicators uses
a Pt100 Platinum RTD which is read by our embedded
processor and displayed on an LED display.
3.1. Safety Instructions
Read the instruction manual completely before installing
the 820/821 Series temperature indicator. All safety
guidelines should be followed and the indicator should
only be installed by qualified personnel following all
local codes and regulations.
3.2. Proper Use
3.2.1. Designated use: These devices are intended for
specific industrial or sanitary applications. Appropriate
fittings, materials and form must be chosen depending on
the use. Proper specification must be done to conform with
temperature, pressure and flow velocity requirements.
3.2.2. Installation: these devices must be installed by
qualified personnel taking all necessary precautions. The
installation should adhere to all local regulations.
3.2.3. Ensure that the label on the 820/821 Series Digital
Temperature Indicator is correct and is appropriate for the
particular application
3.2.4. These devices are repairable. In the event of
failure they should be returned to the factory for repair
and
recalibration. Please ensure the unit is clean and has
no contaminants before returning.
3.2.5. If the installation will occur in
or near hazardous materials all necessary precautions
should be taken.
3.2.6. Mounting locations should be chosen to
avoid high voltage electrical lines and for ease of
installation and future maintenance.
If there is any visible damage to the unit check the
packaging and notify the shipper immediately. Included in
the package should be one temperature probe and one
instruction manual.
4.2. Storage: note that the device should be stored at
a temperature between -40 °C to +85 °C (-40 °F to 185 °F)
in a location that is reasonably dry and clean.
4.3. Orientation:
There are no restrictions on the orientation of the
probe installation location, but if there is a requirement for
the pipe to be self draining the seating should be angled
such that it will drain properly.
The probe should be centered in the process flow no
matter what the orientation. Angled inserts should have
the probe pointing into the direction of flow as shown.
Ensure that during installation all necessary precautions
are taken. If this is a sanitary installation ensure that
the probe has been properly cleaned in advance of
installation and ensure that it is transported to the site of
installation in a way that will maintain it’s sanitary
condition.
If there are flammable or explosive fluids or gasses
present at the site of installation ensure that proper
grounding procedures are taken. Unwrapping a
probe from bubble wrap or other packaging can impart
a static charge on the probe which may discharge
upon insertion into the mounting location.
If the function demands it, seal the process connection
with PTFE tape.
Note: NPT connections should be hand tightened and then
turned only 1-1/2 turns further with an appropriate wrench.
This value may change according to what type of sealant
is used on the pipe threads. Do not use the display body to
tighten the probe into the mounting location. Doing so may
damage the probe. Use only the process connection or
compression fitting for tightening.
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4.4. Trouble shooting
If the unit fails to function properly there are no
user serviceable parts inside. If returning the
unit to NOSHOK, please ensure that the unit is clean
and free from any contaminants before shipping.
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The pressure limits for the probe is 500 psig, but the
pressure limits for the process connection could be
considerably less. Ensure the the appropriate process
connection is used for the desired pressure limits.
5.2. Temperature Limits
The ambient temperature range for the exterior fitting
enclos-ing the processor should not exceed -40 °C to 85 °
C (-40 °F to 180 °F). The temperature limits for the probe
should conform to the unit ordered.
Note that the temperature will affect the pressure and flow
velocity limits of the probe.
5.3. Thermal Characteristics
For some RTD temperature sensors there is self heating
from the measurement resistor. With NOSHOK
820/821 Series Digital Temperature Indicators the
self heating is negligible. Any self heating error will be
com-pensated for during calibration.
Calibration of all NOSHOK Digital Temperature Indicators
takes place after the RTD and processor are installed in
the thermowell and process connection. There should be
no discrepancy in the measurement due to the thermal
characteristics of the probe or process fitting.
Warm up is approximately 30 seconds, then response time
is typically 0.5 seconds. Note that the Digital Temperature Indicator can be ordered with an
averaging function included in the factory calibration.
This would change the response time and increase
it up to as much as 30 seconds.
6. Calibration
Calibration is performed at the factory. For recalibration
return the unit to the factory. Please ensure that the unit
is clean and free of contaminants before shipping. On site
calibration may only be conducted by a
NOSHOK
professionals.
7.
Long-Term stability
The electronics and RTD should not deviate more than%
0.05 per year if sized and installed properly. Regularly
scheduled calibration should be done to ensure that the
unit is within accepted norms.
In the event of returning a unit to NOSHOK for calibration
please ensure that there is no dangerous contaminants on
the unit before shipping.