4SD1-NH3
Installation
General Description
The SD1-NH3 is a single-point sample-draw ammonia sensor. This design
helps the sensor survive in continuous-exposure applications where other
diusion-type electrochemical sensors simply fail and die.
This ammonia sensor utilizes proven electrochemical sensor technology for
accuracy. It is designed with special pump/valve sequencing to refresh the
cell with clean air to prevent ammonia saturation and extend the cell life. An
automatic reverse purge routine also helps self-clean the micron lter.
The SD1-NH3 has a 10-minute sampling rate, and the sample-draw cycle is
as follows:
2-minute sample time from the room being monitored. At the end of the
two minutes, the sample data is stored and held for the next 10 minutes
also while being transmitted via 4-20 mA output to the controller or PLC.
2-minute fresh air purge from outside fresh air source.
6-minute pump shut-o phase.
The standard detection range (0-100 ppm) of the SD1-NH3 sensor provides
monitoring of ammonia concentrations accurately down to 5 ppm without
false alarms.
The SD1-NH3 sensor provides an industrial standard linear 4/20 mA output
signal compatible with most gas detection systems and PLCs. The output
signal is not aected by drastic temperature and moisture variations.
All circuit boards are sealed in potting compound, protecting sensitive
electronic components and copper tracing from corrosion.
An external fresh-air sample tube and hardware are included with the SD1-
NH3. Tube length provided is ve feet.
Locating the SD1-NH3
An important consideration when installing the SD1-NH3 is that it must
be easily accessible for occasional maintenance, and protected from
physical damage (e.g. poultry, livestock). A cage or wire mesh may need to
be constructed to protect the sensor and outdoor air sample tubing from
damage.
For optimum ammonia monitoring of litter, mount the bottom of the sensor
enclosure approximately two to three feet from the oor. Keep in mind,
the indoor air sample port and lter are located at the bottom of the sensor
enclosure.
The external fresh-air port should be mounted to and penetrate through
an exterior wall. This will be the source of fresh outside air necessary for
proper monitoring and longer cell life.
If using for livestock barns where stir fans (circulation fans) are being used,
one SD1-NH3 sensor can adequately monitor 25,000 sq feet.
Installation Guidelines:
• Mount sensor on an exterior wall.
• Mount sensor on a solid surface with minimal vibration.
• Mount sensor thru the holes in the mounting anges of the enclosure.
• Mount sensor in a general-purpose location only. Do not install in a
hazardous environment.
• Mount sensor away from electromagnetic interference.
• Always mount sensor vertically with the sampling port at the bottom.
• Take air movement and ventilation patterns into account.
• Keep sensor and wire runs away from mercury vapor lights, variable
speed drives, and radio repeaters to prevent electrical interference.
• More than one sensor should be installed for highly critical locations.
