Instrumentation Cable Guide
TABLE OF CONTENTS :
CHAPTER 1: WHAT ARE INSTRUMENTATION?
Instrumentation cables are conductor cables. They are used to transmit low digital /electric signals to electrical equipment for their monitoring and control.
These cables are in use in a broad range of industrial applications. They can evenly transmit electricity from one instrument to another and keep operations balanced and checked.
Such cables are not only used in power transmission but can also perform essential functions. They make sure that the functioning of the industries is carried out.
The design is sturdy and rigid, which can withstand harsh environmental conditions. We can use instrumentation cables in both wet and dry locations, such as sea bed refineries and any space modules.
Instrumentation cables have a maximum conductor temperature of 90°C and a low temperature of -40°C. Because of this, we can make use of these cables in any environment.
We can use these cables in a microprocessor or computerized instruments, such as walkie talkies or large MRI scanners.
The instrumentation cable has a jacket that is sunlight resistant and has protection from moisture and vapor penetration.
If you want to transmit signals without penetration of noise, instrumentation cable is the ideal choice. They are prone to external sounds because of low messages and therefore work efficiently.
Instrumentation cables are available in many designs, colors, shapes, and sizes. You can customize these according to the requirement, which will equip you with the perfect cable.
CHAPTER 2: HOW ARE INSTRUMENTATION CABLES CONSTRUCTED?
The construction of instrumentation cables depends upon its usage. The usage of cables will determine which kind of cable shielding or construction material should be in use.
CHAPTER 2.1: CONDUCTOR IN INSTRUMENTATION CABLE:
Cable conductor consists of one wire or multiple wires not insulated from each other. Conductor material includes various conductive metals.
We use stranded copper or aluminum as the conductor. We make use of copper because it is denser and more substantial than aluminum.
At the same time, copper is more conductive. It is also corrosion-resistant. Its conductivity is because copper has a greater outer radius, and its valence electrons are stable.
Electrically equivalent aluminum conductors have a cross-sectional area that is 1.6 times larger than copper, but they are still half the weight.
We also make use of conductors that are constructed of steel and are cladded with an aluminum or copper shell.
We make use of American Wire Gauge (AWG) for measuring conductor size. The higher the AWG number is, the smaller will be the diameter and thickness of the wire.
Thicker wires are less resistant and, therefore, can transfer more current.
Since instrumental cables are in use for a diverse range of applications, the number of conductors depends upon the usage of these wires.
CHAPTER 2.2: JACKET AND INSULATION:
Instrumental cables consist of a jacket and insulation. The purpose of the jacket and insulation is to prevent leakage of current from the conductor.
Insulation material also depends upon the application of cables.
Ethylene Propylene Diene Elastomer (EPDM) provides excellent flexibility even in different temperatures.
Neoprene, which is a synthetic rubber, is used when cables have a probability of coming in contact with chemicals. This type of insulation is oil, flames, and chemicals resistant.
Silicon rubber possesses excellent flexibility, but it is not resistant to fluid, thereby you should not use it in water applications.
Thermoplastic is another excellent insulating material. Types of thermoplastic include Polyethylene (PE), polypropylene, polyvinyl chloride (PVC), Teflon, and Tefzel.
Mica tape is another insulation material that offers excellent resistance to temperature.
Each of these materials has its unique properties. However, if you choose the material-specific for a particular condition based on its specifications, it will be longer-lasting and durable.
CHAPTER 2.3: INDIVIDUAL SCREEN:
The individual screen is then used on the top of insulating material to protect from noise, radiation.
In industries, large machines and pieces of equipment tend to create a lot of noise / electrical interference.
Because of this noise, there is a chance of disrupting the clarity of signals. The noise will manipulate signals and would result in inaccurate readings.
For example, if a system is monitoring a specific temperature, it will provide false readings due to noise generated from other pieces of equipment.
But if you install a metallic screen, this noise would be canceled. The sound would remain on the outside, and the system would be able to provide accurate readings.
Thus, this screen prevents intrusion caused due to other conductors. Different braid screens as Metallic (copper, aluminum) or semi-metallic (PETP / Al) tape is in use.
CHAPTER 2.4: ARMOR:
On top of the individual screen, armor made of steel or braid is put to use. As the name suggests, armor is in use for the protection of conductors.
In cases where steel armor cannot be in use, galvanizing is carried out. It protects the cables from corrosion.
CHAPTER 2.5: OUTER SHEATH:
Outer sheath, made of thermoplastic (PVC) or thermosetting (CSP) compound, this installation is on top of the armor for additional protection.
The outer sheath comes color-coded. Colour coding as denotation so we can see the difference between LV, HV, and instrumentation cables.
On the outer sheath, the manufacturer’s markings and length markings are also in print, which will give you a clear indication of the cable’s location and specifications.
On the base of the instrumentation cable, there is a black jacket. The jacket also comes color-coded so that multiple cables can be differentiated.
CHAPTER 2.6: SHIELDING:
Electromagnetic shielding material is in the provision below the outer jacket in instrumentation cables.
Material may be of metal, either braided or foiled or taped.
This shielding is carried out to prevent transmitted signals from being affected by electrical noise.
Another advantage of shielding is that it reduces electromagnetic radiation coming from the cables themselves.
Thus, your cables will be incomplete protection from any short circuit or damage.
CHAPTER 3: WHAT ARE THE APPLICATIONS OF INSTRUMENTATION CABLES?
Instrumentation cables have a diverse range of applications, which are not only limited to one thing. They are designed to have excellent mechanical, physical, electrical properties.
Their installation is effortless and is free from any hindrance, which is why they are in preference over other cables everywhere.
In today’s world, everyone is busy 24/7 and barely manages to find time out of their schedule. In such a fast-growing world, instrumentation cables are the ideal choice for you.
They save time, money, and energy.
Industries make use of instrumentation cables because of their durability and highly advanced features. These include :
|Oil and gas industries.
|Manufacturing (Steel, Cement, Pulp & Paper).
|Food & Beverage.
|Intelligent Transport & Traffic Systems.
Instrumental cables are in support of messenger wire in outdoor use; therefore, we can also make use of these in raceways.
Places where noise becomes a problem, instrumental cables can come of use because they are noise cancellers and are prone to external noise.
Designing of Instrumentation cables is such that they can transmit signals without any hindrance or interference. Hence, we can use them from small to large scale instruments.
We can use instrumental cables in microprocessor-based or computerized instrumentation systems.
Instruments that are in use for communication with one another also make use of instrumentation cables. An example is that of a walkie talkie.
The walkie talkie is in use for communicating voice messages over a specific range. This transmission is possible due to instrumental cables.
The Voice signals are transmitted from one person to another without any external noise.
Instrumental cables are protected and designed with precision. We can make these cables to be armored, laid up, in triads, quads, and adequately screened, etc.
CHAPTER 4: WHAT ARE THE FEATURES OF INSTRUMENTATION CABLES?
Each operation and material used in the construction of instrumentation cables has its features. The more coatings and materials installed, the better the cable would become.
Instrumentation cables are :
- Moisture and corrosion resistant.
- They are Chemical resistant due to the protection of the lead sheath.
- Resistant to oil, hydrocarbons, solvents, etc. due to the oil resistant sheaths.
- They are also mud resistant and can be in use in muddy places.
Instrumentation cables consist of insulation in PVC (Polyvinyl chloride), HEPR (Hard grade ethylene, propylene rubber), XLPE (Cross-linked polyethylene), PE (Polyethylene).
These cables are also sheathed in PUR (Polyurethane), LSF (Lysophyllene), and PE (Polyethylene).
Instrumentation cables have including and up to 1.1 kV low voltage grade and above 1.1KV high voltage grade.
Instrumentation cables have a Gauge of 4/0 to 30AWG.
Instrumentation cables are also resistant to magnetic fields. Thus, we can get rid of unnecessary intrusions and obstacles in its functioning.
Armoring on top of the instrumentation gives it protection against getting crushed or being cut. Tensile strength also increases due to armoring.
Termites and rodents cannot damage the instrumentation cable. Our cables are rigid and flexible on the outside, which makes them prone to damage.
Instrumentation cables are quite different from other cables, and this is because these cables are pair constructed and provided with shielding.
However, if we consider other cables such as control cables, those are generally core constructed.
Another feature of instrumentation cables is that they are sunlight resistant. They help in saving material, labor cost, and require less maintenance.
Due to their durability, most of people prefer instrumentation cables.
Changing environmental conditions have no impact on the efficiency of instrumentation cables because of their high-temperature tolerance.
Instrumentation cables are highly flexible. Due to their flexibility, we can make use of these in almost any environment and space.
They work great in the long run because they are durable. These cables require less maintenance, which is something every consumer is looking for in the longer term.
Instrumentation cables have aluminum or steel armor. This armor provides mechanical protection as well as the ability to work in 600V to 300V.
They have a normal conductor size of 0.5, 0.75, 1.0, 1.5 & 2.5 Sq.mm
There are various standards according to which instrumentation cables are designed. Such as BS-EN-50288, EIL 6-52-46, etc.
The outer coating in instrumentation cables is usually made up of PVC, also known as Polyvinyl chloride. It is one of the most popular materials used in the construction of wires.
PVC is made up of thermoplastic resin through the process of polymerization (reaction in which monomer molecules combine to form polymer chains.)
Because of this polymerization, the material gains specific properties. Such as fire and flame resistance, abrasion resistance, corrosion resistance, moisture resistance, etc.
PVC is such a material that is useful in outdoor environments. It is sturdy and rigid and can withstand sunlight and extreme weather conditions, such as cold, heat, rain, etc.
Because of all these properties, we consider PVC as the best and most efficient construction material for instrumentation cables.
Color coding is carried out in these cables. This color-coding depends upon the core construction, such as five cores, two cores, four cores, etc.
The color coding for the two cores is red and black. For three cores, color coding is red, yellow, and blue. For four cores, Red, yellow, blue, and black coding is in use.
For five cores, color coding includes red, yellow, black, blue, and grey.
In the case of cores above 5, we install one yellow core and one blue core with grey color in each layer. In this case, the usual way is to print numbers on these cables.
This color-coding is carried out for distinction so that every cable is easily recognizable and is easy to be installed and maintained.
CHAPTER 5: WHAT ARE THE TYPES / MODELS OF INSTRUMENTATION CABLES?
There are three basic types of instrumentation cables. Thes include Power cable, control cable, and signal cables.
These are basically in use for industrial applications. They are used to transmit pneumatic, electrical, electronic signals from one point to another.
However, a single protocol is applied — both for transmission and receiving of information.
|CHAPTER 5.1: POWER CABLE:
|Power cables are in use for transmitting electrical power. These consist of one or more electrical conductors that are usually held together with an overall sheath.
|CHAPTER 5.2: CONTROL CABLE:
|These cables are mainly in use for energizing relays, contactors, control systems, and low voltage devices or equipment.
|CHAPTER 5.3: SIGNAL CABLE:
|These cables are in use for Telephone cable, radio frequency cable, computer, and data cable. Signal cables transmit low voltage and RF signals.
|There are other different models of instrumentation cables also available. Each model depends upon the application of these cables. Other types may also include :
|CHAPTER 5.4: ARCNET CABLES:
|Archnet cables are useful in ARCNET networks, which work at a relatively high speed. These cables are token-based.
|Archnet cables are used for local area network (LAN) communications from one industrial computer to another. Their high speed makes it perfect for a fast connection.
|CHAPTER 5.5: AS-I CABLES:
|AS-I cables are two two core cables that provide power and allows the transfer of data. They are used to exchange sensors, actuators, and other AS-I instruments/ systems.
|CHAPTER 5.6: CANBUS CABLES:
|The motor vehicle industry uses bus cables. These cables are designed to withstand the harsh electrical environment, which means they are incredibly durable.
|They are in use for high speed, serial data networks for communication.
|CHAPTER 5.7: CAN OPEN CABLES:
|Field protocols that are on bases on can bus are the reason these cables are in use. These cables are useful for industrial communication.
| CHAPTER 5.8: DEVICE NET CABLES:
|Device net cables are used for connecting devices, as the name suggests. Devices such as limit switches, photoelectric cells, valve manifold, motor starters, drives, and operator displays.
|These cables also use the controller area network (CAN) and operator displays to programmable logic controllers (PLCs) and personal computers.
|CHAPTER 5.9: FIELD BUS CABLES:
|The Field bus environment is a base level group in the transition of plant networks. These cables are in use for connecting industrial devices such as actuators, sensors, transducers, and controllers.
|CHAPTER 5.10: FOUNDATION FIELDBUS:
|Foundation field bus cables serve as LAN for plant instrumentation and factory control devices. They are useful in all-digital, two-way communications within industries.
|CHAPTER 5.11: HART CABLES:
|Hart cables are in such a design that they can allow communications without interruption. These cables get updates per second from a field to devise through a host application.
|CHAPTER 5.12: PROFIBUS CABLES:
|PROFIBUS cables are in use for manufacturing purposes. These cables use a vendor-independent Field bus standard that is suitable for process automation.
|CHAPTER 5.13: P-NET CABLES:
|P-Net cables are designed as per European standard (EN 50 170 Vol. 1). These standard cables are now a part of the International Field bus Standard (IEC 61558 Type 4).
|You can also obtain some other types of instrumentation, i.e., Power cordage cables and multi-conductor cables. Both have their different applications :
- Power cordage cables are those which are used to produce power chords. These do not include the end connectors. They are mainly used mainly in low voltage, commercial, and domestic applications.
- Multi-conductor cables include cable shielding. These consist of a single wire or a combination of wires with two or more conductors.
CHAPTER 6: WHAT MATERIALS ARE IN USE FOR CONSTRUCTION?
The choice of material for instrumentation cables depend upon various factors, such as:
- Outdoor or indoor environmental conditions (humidity, temperature, solar radiation)
- The procedure through which installation is carried out. (indoor, outdoor, direct buried, on trays, etc.
- It depends on the possibility of oil or chemical spills or abrasion.
- Behavior in fire (low smoke, zero halogens to avoid toxicant)
- Flame or fire resistance etc.
As per the factors mentioned above, the materials for the construction of cables can be in consideration. It all depends on what and where you are going to use the cables.
Instrumentation cables, however, are made from a variety of materials. Each material gives these cables its unique features :
- Polyvinyl Chloride (PVC)
- PVC/Nylon (VNTC)
- Thermoplastic Elastomer (TPE)
- Cross-linked Polyethylene (XLPE)
- Chlorinated Polyethylene (CPE)
CHAPTER 7: WHAT ARE THE ADVANTAGES OF INSTRUMENTATION CABLES?
Instrumentation cables that are well coated and sheathed have innumerous advantages, such as:
|Protection from the entrance of hydrocarbons.
|Protection against moisture or humidity.
|It can be useful as an earthing or grounding system.
|Excellent corrosion resistance.
|Excellent weather resistance.
CHAPTER 8: WHAT ARE THE PRECAUTIONARY MEASURES UNDERTAKEN?
Instrumentation cables come with several advantages and properties. But some necessary precautions are required to undertake:
|Keep the instrumentation cables as far away as possible from other power cables to avoid crossing.
|In case distancing is not possible, keep both instrumentation cables at a right angle.
|Carry out the installations with extreme care so that there are no loops formed. Loop would result in creating interference.
|Install the power line away from instrument cables.
|The minimum distance should be 30 cm.
|Keep away any wire carrying an AC signal of 120V away from instrument cables.
|These wires would create interference, and as a result, false readings would be provided by the system.
|Always install instrumentation cables in the conduits that are specifically designed for them.
|Install separate trays; they are a less costly solution.
|Two 12 inch trays cost the same as 24-inch trays.
|The separate trays would save maintenance costs later in the future.
|Install all instrumentation cables in steel conduit.
|Steel conduit would provide an excellent electromagnetic shield and would dampen it when properly grounded.
|Connect all metallic equipment directly to the ground to avoid short circuits and electromagnetic interference.
|Insulate all instrument ground wire. Do not leave these cables bare.
|Be careful during instrument wiring design. Make sure each shield is in a connection to a single ground point.