Installation Instructions for Accelerograph with GPS Antenna Inside a Building


This guide outlines the comprehensive steps for installing an accelerograph and its accompanying GPS antenna within a building structure. It covers mounting procedures, necessary clearances, and accessibility considerations to ensure optimal performance and ease of maintenance.

Tools and Materials Required

  • Drill and drill bits
  • Mounting brackets and hardware (screws, anchors, etc.)
  • Screwdriver
  • Level
  • Measuring tape
  • Cable conduits (if necessary)
  • Sealant (for outdoor installations)

Pre-Installation Planning

  1. Location Selection: Choose a location that minimizes vibrations from non-seismic sources (e.g., heavy machinery, and HVAC systems). Ideally, the accelerograph should be positioned close to the building’s structural core. It is better to install it on the floor inside an NEMA enclosure.
  • GPS Antenna Placement: The GPS antenna requires a clear view of the sky to maintain satellite communication. It should be placed on or near a window sill or mounted externally with a clear path to the sky, avoiding obstructions such as tall buildings or heavy foliage. The GPS provides absolute timing to the instrument for time-stamping of the waveforms recorded.
  • Accessibility: Ensure the installation site is easily accessible for maintenance and data retrieval. An access panel or removable ceiling tiles are recommended for indoor installations.
  • Clearances: Maintain at least 1 foot (~0.3 meters) of clearance around the accelerograph for ventilation and to ensure unobstructed access.

Installation Steps

  1. Mounting the Accelerograph:
  • Use the measuring tape and level to mark the drill point for the mounting anchor ensuring the accelerograph will be level.
    • Drill a hole at the marked point and insert the anchor.
    • Secure the mounting anchor with a screw.
    • Attach the accelerograph to the mounting anchor following the manufacturer’s guidelines.

Example of floor mounting

In the following picture, you can see a floor-mounting installation of a unit with an internal sensor with the use of a bolt in the concrete.

Drawing is courtesy of SARA

The leveling pads do not necessarily need the counter-lock paddle (not drawn in the figure), even if it is always good to have. They would work in a counteraction, so the paddles shall be adjusted forcing the sensor to go up, while the bolt keeps it fixed down.

Photo is courtesy of SARA

The same principle will work for wall and ceiling installations as follows.

Example of wall mounting or ceiling

If the unit needs to be mounted in buildings, it often requires a vertical or ceiling-flipped installation. In these cases, is essential to use the central key-hole hooking slot.

Drawing is courtesy of SARA

In both cases, especially for mounting equipment over 1 meter of elevation we absolutely recommend the use of a safety chain or steel cord.
It can be anchored to any suitable threaded hole. If necessary and appropriate you may decide to use 2 or more threaded holes to anchor the safety cord.
All safety retention devices must be checked every year. To be on the safer side a shaft or a large steel baseplate could be used instead of the use of a dowel.

Appropriate heavy-load dowel and proper bolt are necessary to anchor this way, also depending on type of material the wall is made of, concrete, bricks, etc.

The bolt head should be of 12 mm, maximum of 14 mm to allow a proper leveling degree of freedom. The diameter of bolt stem should be not less than 8 mm for wall or ceiling mounting.

NOTE – 1: It is very important to have a safety bonding for the wall and ceiling mount and check the tightness of it periodically else vibrations will be wrongly measured.

NOTE – 2: Do not overtight the feet else the case will be damaged.

  • Installing the GPS Antenna (if applicable):
  • If mounting externally, ensure the antenna is positioned securely with a clear view of the sky. Use a sealant to waterproof any drill holes.
    • For window placement, ensure the antenna is as close to the glass as possible, avoiding metal frames that might obstruct signal reception.
    • Route the antenna cable to the accelerograph, avoiding sharp bends. Use cable conduits if necessary to protect the cable from damage.
  • Cabling and Power Connection:
  • Connect the GPS antenna to the designated port on the accelerograph.
    • Ensure all cables are neatly routed and secured.
    • Connect the accelerograph to a power source, using a surge protector. Make sure that the power outlet is grounded.
  • Initial Setup:
  • Follow the manufacturer’s instructions to power on and configure the accelerograph.
    • Verify the GPS connection and perform any required calibrations.
  • Testing:
  • Conduct initial tests to ensure the accelerograph is recording data accurately.
    • Verify that the data can be retrieved and is consistent with expectations.


  • Documentation: Keep a record of the installation details, including the location, date of installation, and any specific configurations.
  • Maintenance Schedule: Establish a regular maintenance schedule to inspect the accelerograph, its connections, and the surrounding area to ensure continued accuracy and performance.


  • Always refer to the manufacturer’s installation guidelines for specific instructions related to your accelerograph model.
  • Consider local building codes and regulations when installing external components.
  • For installations in areas with extreme weather conditions, additional protective measures may be required for the outdoor components.

By following these comprehensive instructions, you can ensure the successful installation of an accelerograph and its GPS antenna within a building, facilitating accurate seismic data collection and analysis.


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