Emerson Net Safety MLP-A-SC1100, User Manual

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Operations Manual
FGD-MAN-0047 January 2017
3
Section 2: Plan
2.1 Locate controller / sensor
Prior to the installation process, a location plan for placing the
controller and sensor should be developed. Although there are no
absolute rules determining the quantity and location of a sensor or
controller, the following points should be considered when planning
the installation.

Locate the controller where it will be accessible and visible.

Carefully locate sensor in an area where gases may potentially
accumulate.

Use redundant systems to enhance protection and reliability.

Light gases tend to rise; heavy gases tend to accumulate in low
areas.

Consider the air movement patterns within the facility.

Consider the construction of the facility (such as trenches where
heavy gases may accumulate or peaks where light gases may
accumulate).

Seek advice from experts knowledgeable about the primary gas to
be detected.

Use common sense and refer to the regulatory publications that
discuss guidelines for your industry. The two most common
installations options are as follows.
2.2 Option 1
Locate the sensor separate from the controller using a Certified
Junction Box. If the Net Safety Multi-Purpose Junction Box is being used,
refer to MAN-0081 for terminal designations.
The controller is located near eye level. The conduit is run from the
controller to the sensor. A calibration cup (CCS-1) can be attached to
the sensor. Tubing can be run from the CCS-1 to a convenient location
accessible for calibration gas to be injected.
2.3 Option 2
The sensor is attached directly to the controller. See Figure 2-1 for
details. The CCS-1 and tubing is used to facilitate calibration.
TIP: The calibration cup (CCS-1) allows for tubing to be affixed to a
sensor mounted in remote locations. The tubing is directed to a level,
usually close to the controller, for easy injection of calibration gas. The
calibration cup can also act as a splash guard, protecting sensors
mounted low to the ground.
Figure 2-1 Locate sensor/controller - separated