How to Install and Position a Monitoring Prism

 

Correct installation is important when using a fixed monitoring prism for repeated total station observations.

 

A monitoring prism that becomes loose, changes orientation or is installed in an unsuitable position can affect the consistency of monitoring measurements.

 

The Myzox TK-10S / TK-10 Monitoring Prism L-Bar Type is designed for fixed monitoring applications and provides X/Y directional adjustment to help surveyors establish an appropriate target orientation.

 

This guide explains the main factors to consider when planning a monitoring prism installation for structural and deformation monitoring in Malaysia.

 

MTM Precision Sdn. Bhd. is an authorized distributor of Myzox in Malaysia.

 

Step 1: Determine the Monitoring Objective

 

Before installing any prism, determine what needs to be monitored.

 

Typical applications include:

 

Building movement

 

Retaining wall movement

 

Bridge deformation

 

Slope movement

 

Deep excavation

 

Structural displacement

 

Construction-related movement

 

Infrastructure deformation

 

The monitoring objective influences where targets should be positioned.

 

Step 2: Select the Monitoring Point

 

The prism should be installed at a location that represents the point the project team intends to monitor.

 

Depending on the structure, this may be on a:

 

Concrete wall

 

Building façade

 

Structural column

 

Retaining structure

 

Bridge element

 

Other suitable fixed surface

 

Monitoring point selection should follow the project's surveying and engineering requirements.

 

Step 3: Check the Mounting Surface

 

The prism needs a secure installation.

 

Before installation, check whether the selected mounting surface is suitable and stable.

 

Avoid locations where the mounting point itself may become loose or damaged independently of the structure being monitored.

 

A monitoring system is only useful when the target represents the intended structural point.

 

Step 4: Consider Total Station Line of Sight

 

Before fixing the prism permanently, confirm that it can be seen from the intended total station observation location.

 

Ask:

 

Is the prism visible?

 

Will future construction block the view?

 

Could scaffolding obstruct it?

 

Could temporary structures block the line of sight?

 

Will parked machinery or equipment create problems?

 

Can the total station observe the target from a stable position?

 

A monitoring prism that becomes permanently obstructed cannot serve its intended purpose effectively.

 

Step 5: Orient the Prism Toward the Total Station

 

The prism should be suitably oriented toward the total station.

 

The Myzox TK-10S / TK-10 provides X/Y directional adjustment, allowing the surveyor to adjust the target orientation during installation.

 

This is particularly useful when the mounting surface does not directly face the total station.

 

Correct target orientation helps establish suitable observation geometry.

 

Step 6: Secure the Monitoring Prism

 

The prism should be firmly attached according to the intended installation arrangement.

 

Once installed, check that the assembly does not move under normal site conditions.

 

The target should not be treated like a temporary survey accessory.

 

For monitoring work, it becomes part of the measurement reference system.

 

Step 7: Assign a Monitoring Point ID

 

Every prism should have a clear identification number.

 

For example:

 

MP01 – Building North Wall

MP02 – Building East Wall

MP03 – Retaining Wall Section A

MP04 – Retaining Wall Section B

MP05 – Bridge Pier

 

Clear identification reduces the risk of mixing up targets during repeated observations.

 

Step 8: Confirm the Prism Constant

 

The Myzox TK-10S / TK-10 has a specified:

 

Prism Constant: -25 mm

 

The appropriate prism setting should be configured in the total station according to the instrument manufacturer's instructions.

 

This should be checked before establishing baseline measurements.

 

Using inconsistent prism constants between observation sessions can introduce systematic measurement differences.

 

Step 9: Establish Stable Survey Control

 

A monitoring prism is only one component of the monitoring system.

 

The total station must observe the prism relative to stable survey control.

 

Reference points should be located appropriately so that movement of the control network does not become confused with movement of the monitored structure.

 

A typical arrangement is:

 

Stable Reference Points → Total Station → Monitoring Prisms

 

Both sides of this measurement relationship matter.

 

Step 10: Record the Baseline Measurement

 

Once installation and survey control have been checked, establish the initial measurement.

 

This becomes the baseline.

 

Record information such as:

 

Monitoring point ID

 

Coordinates

 

Elevation where applicable

 

Date and time

 

Instrument used

 

Prism model

 

Prism constant

 

Observation station

 

Relevant site notes

 

Future observations can then be compared against this reference data.

 

Step 11: Photograph the Installation

 

Photographs can be useful for documenting monitoring points.

 

A site record can include:

 

Overall location photograph

 

Close-up of the prism

 

Monitoring point ID

 

Orientation

 

Nearby reference features

 

This helps future survey crews identify the correct target and recognize whether the installation has been physically disturbed.

 

Step 12: Repeat Measurements Consistently

 

Monitoring is based on comparison.

 

Where practical, repeated observations should follow a consistent procedure.

 

For example:

 

Baseline → Week 1 → Week 2 → Week 3 → Week 4

 

or

 

Pre-Excavation → Excavation Stage 1 → Stage 2 → Stage 3 → Completion

 

Maintaining consistent measurement procedures helps improve the usefulness of comparisons between observation periods.

 

Where Should You Avoid Installing a Monitoring Prism?

 

Avoid locations that are likely to:

 

Be demolished during construction

 

Become hidden behind scaffolding

 

Be covered by temporary structures

 

Be frequently hit by machinery

 

Experience unrelated local movement

 

Become inaccessible

 

Lose line of sight

 

Be intentionally modified during construction

 

Thinking about future site conditions during initial installation can prevent monitoring problems later.

 

What Happens If the Prism Is Knocked?

 

A physically disturbed prism should not automatically be treated as if it still represents the original baseline point.

 

If the prism has been:

 

Hit

 

Loosened

 

Rotated

 

Removed

 

Reinstalled

 

Damaged

 

the monitoring team should inspect the installation and follow the project's procedure for handling a disturbed monitoring point.

 

Simply measuring it again and comparing it directly with the old baseline could produce misleading results.

 

What If the Prism Is No Longer Visible?

 

Construction sites change continuously.

 

Scaffolding, hoarding, cranes, temporary structures and equipment can block line of sight.

 

If a target becomes obstructed, the survey team should assess alternative observation arrangements according to the monitoring plan.

 

This is why visibility throughout the expected project duration should be considered before installation.

 

How Many Monitoring Prisms Should Be Installed?

 

There is no fixed number suitable for every project.

 

The required number depends on:

 

Structure size

 

Monitoring objective

 

Expected movement

 

Project geometry

 

Observation distance

 

Required coverage

 

Engineering requirements

 

Visibility

 

Large retaining walls, buildings or infrastructure structures may require multiple targets.

 

Myzox TK-10S / TK-10 Specifications

 

SpecificationDetailsModelsTK-10S / TK-10TypeMonitoring Prism L-Bar TypePrism Diameter1 inch / 25 mmPrism Constant-25 mmPrism Height60 mmBeam Deviation5″DimensionsH90 × W86.5 × D30 mmWeightApprox. 207 gAdjustmentX/Y direction

 

The compact L-bar design is well suited to fixed monitoring points where a conventional prism pole setup would be impractical.

 

Common Monitoring Prism Installation Mistakes

 

Several practical mistakes can reduce monitoring consistency:

 

Incorrect Prism Constant

 

Always confirm the prism setting before measurement.

 

Poor Target Orientation

 

Make sure the prism is suitably oriented toward the total station.

 

Weak Mounting

 

A loose target cannot provide a reliable fixed monitoring point.

 

Poor Line of Sight

 

Consider how the site will change during construction.

 

Unstable Survey Control

 

Reference points must also be suitable for monitoring work.

 

No Point Identification

 

Clearly label and document every target.

 

No Baseline Records

 

Without reliable initial observations, future comparisons become more difficult.

 

Monitoring Prism Installation Checklist

 

Before accepting a monitoring point, confirm:

 

Monitoring location selected correctly

 

Mounting surface suitable

 

Prism securely installed

 

Prism orientation checked

 

X/Y adjustment completed where required

 

Total station line of sight confirmed

 

Prism constant confirmed

 

Point ID assigned

 

Location photographed

 

Baseline measurement completed

 

Reference control verified

 

Monitoring record created

 

Applications for Myzox Monitoring Prism

 

The TK-10S / TK-10 can support:

 

Building movement monitoring

 

Retaining wall monitoring

 

Bridge monitoring

 

Slope monitoring

 

Deep excavation monitoring

 

Structural deformation monitoring

 

Construction monitoring

 

Infrastructure monitoring

 

Myzox Monitoring Prism Supplier in Malaysia

 

MTM Precision supplies Myzox monitoring prisms, surveying accessories and total station equipment in Malaysia.

 

We support surveyors, contractors, engineering consultants and monitoring professionals requiring equipment for repeated deformation and movement measurements.

 

MTM Precision also provides total station calibration and surveying instrument service in Malaysia.

 

Contact MTM Precision

 

MTM Precision Sdn. Bhd.

Myzox Authorized Distributor in Malaysia

 

Showroom & Service Centre

No. 29-1 & 29-2, Jalan Bandar 18,

Pusat Bandar Puchong,

47160 Puchong, Selangor, Malaysia.

 

Website: www.mtmpre.com.my

Email: mtmpre@yahoo.com

WhatsApp: +6016-6607346

 

Contact MTM Precision for Myzox TK-10S / TK-10 Monitoring Prism price, availability, installation enquiries and surveying equipment support in Malaysia.