Plain answer

How to Add Remote Monitoring to Equipment You Already Have

The plant works. You just cannot see it from anywhere except standing in front of it. That is a smaller problem than replacing it, and it is priced very differently.

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Good news first

Most working plant can be read without being replaced

There is a common assumption that monitoring older equipment means replacing it. Usually it does not. A great deal of installed plant already produces the signals you want, and the job is getting those signals somewhere they can be seen rather than generating them again.

Motor starters have auxiliary contacts. Breakers have status. Many drives, meters and controllers installed in the last twenty years have a communication port that nobody ever connected. Where none of that exists, a sensor can often be clamped or strapped on without breaking into the process at all.

What decides the cost is not the age of the equipment. It is how much has to be switched off to connect to it, and how accurate the existing documentation turns out to be.

Approaches

Four ways to get a signal off existing plant

In rough order of disruption. The first two often cover more than people expect.

Use the port that is already there

Drives, meters, controllers and protection relays frequently have a Modbus or Ethernet port that was never used. If the equipment is on a supported firmware, this is the cheapest route by a wide margin: no process interruption, no new sensors, and the data is already calibrated.

Non invasive sensors

Clamp on current transformers, strap on temperature sensors, clamp on ultrasonic flow meters, vibration sensors on a bearing housing. Nothing is cut into, nothing is drained, and in many cases nothing is switched off. Accuracy is lower than an in line instrument and is usually good enough for monitoring.

Hard wire to existing contacts

Running wiring from starter auxiliaries, breaker status contacts and existing float switches into a new marshalling panel. This needs the board to be worked on, so it needs an outage window, but it uses signals that already exist.

New instrumentation

Where the measurement genuinely is not there: an in line flow meter, a pressure transmitter into a tapping, a level probe. This is where a shutdown, a drain down or a mechanical modification becomes unavoidable, so it is worth confirming the other three cannot answer the question first.

Process

How a retrofit job should be run

Survey first, and pay for it properly, because on plant of any age the drawings and the reality differ
List what signal you actually want before deciding how to get it, since the list usually shrinks
Confirm firmware and protocol on anything with an existing port, because an old firmware can rule it out
Identify which items need an outage and batch them into one window rather than several
Add a marshalling panel with spare capacity, since the second phase always comes
Decide the communication path early, as it is often the longest lead item
Prove every point from the device to the screen, not from the panel to the screen
Record what was found during the survey, because it is often the most valuable deliverable

Track record

Retrofits onto somebody else's installed plant

Every one of these connected to or replaced equipment installed by another party, on assets that stayed in service.

Upgrading and replacement of GE SCMS, TAQA Transmission

TAQA - Transmission

Date2022-01-16

CategoryAutomation, Panel Building

TAQA DISTRIBUTION - ALKHAZNA substation 33 KV - 11 KV

TAQA Distribution

Date2025-03-25

CategoryAutomation, Panel Building

BMS & Chiller Modification in MLC-MEA Learning Centre ADNOC

Schlumberger Technical Services Inc.

Date2016-11-17

CategoryAutomation, Panel Building

ADWEA Enterprise GIS Upgrade

ADWEA

Date2016-11-22

CategoryAutomation

See all 19 delivered projects →

Common questions

Questions we are asked about this

Can you monitor equipment without replacing it?

In most cases yes. A lot of installed plant already generates the signals, either through a communication port nobody connected or through auxiliary contacts already wired in the panel. Where the measurement genuinely does not exist, clamp on and strap on sensors can often add it without interrupting the process.

Do you have to shut the plant down to add monitoring?

It depends on the route. Reading an existing communication port normally needs no interruption at all. Clamp on sensors usually need none. Wiring into an existing board needs an outage on that board. In line instruments need the process broken into. That is why the survey matters: it tells you which of your wanted signals are cheap and which are expensive.

How old can equipment be and still be monitored?

Age matters less than what the equipment exposes. A thirty year old motor starter with an auxiliary contact is easy. A fifteen year old controller with a proprietary closed protocol and no documentation can be harder than either. The question to ask about any item is what signal it already produces and how you would get at it.

What does a retrofit monitoring project cost?

The equipment is rarely the main cost. Cabling, the outage windows, the survey and the commissioning are. A quotation that is mostly hardware with a thin allowance for installation is usually a quotation that has not surveyed the site.

Can this be done in stages?

Yes, and it usually should be. Start with the plant whose failure costs most, prove the communication path and the head end work, then extend. Specify the marshalling and the communication capacity for the full scope at the start so the later phases are additions rather than rebuilds.