from the Forum department...Customized Control System ExD Enclosure
We have procured a Customized PLC ExD Enclosure.
Check the certificate number of the enclosure as supplied. If it has a suffix -U, this indicates...
from the automation department...Difference Between Full Load and Rated Conditions
Confused between the terms full load and rated conditions.
For a pump driven by an electric motor, the rated voltage of the motor is the nominal value of the...
from the Electrical department...Generator capacity
Calculation of capacity of generator.
Since the rating of a generator is expressed in terms of power, with a base of watts, and you have...
from the Forum department...Different modes of AVR operation
Brush AVR A-30 different modes of operation?
The use of pu (per unit) is widespread in electrical calculations as it allows the voltage...
CSA, Oh dear, oh dear, oh dear! I thought we had dealt with the subject of "reactive...
from the Forum department...Excitation system
What is an excitation system is and what role it does play in the start up of a prime mover like a gas turbine
What else happens at the same time? If by "island mode" you mean that your plant is...
from the Advice for a newb department...Modbus "pollsets"
Need advice on creating pollsets in Isagraf
Why do you need to use 3xxxx registers? These are "read-only" as they are set by the...
from the Forum department...Controlling flow and pressure to a spray ball
How to control flowrate and pressure with a positive displacement pump.
A positive displacement pump is essentially a constant-flow device, with discharge pressure...
from the Electrical Power Engineering department...Power System Control & Stability
What happens when power system is subjected to any kind of disturbance?
Hi Asif, > And there is a balance between input mechanical torque and output electrical...
Let's try a simpler model first. Think about someone water-ski-ing. In the usual case, the...
For a system to oscillate, it must usually have two forms of energy storage and some means of...
from the Maintenance department...Endress+Hauser Level Transmitter Hunting
What is the possible cause for Level transmitter hunting?
One possible reason for a level loop being reported as "hunting" is a phenomenon called...
from the The Unknown Entity department...One control variable for two loops
Can we have one control variable control two different loops?
Power in a pressure system = volumetric flow x pressure drop. If the system has a high flow, then...
One approach which I have seen used with boiler feedwater pumping systems is to use the valve to...
from the Forum department...Floating point in little endian can be read in big endian but value not same.
Reading IEEE little endian format data
Are here any values in the system that are in a known range? I'm thinking something like base...
from the Safety department...EEx 'd' or IS
What are the criteria in deciding between EEx 'd'/'e' and Intrinsically Safe?
If it's mandatory to use all Zone 0 instrumentation, the Ex ia is your ONLY option - Ex d is not...
from the Forum department...Transmission line safe distance from Gas Vent tower
220 KV transmission line safe distance from the Gas vent tower.
The installation standard for Australia and New Zealand AS/NZS 60079.14 (modified from IEC...
from the Forum department...Comparing steam flow and feedwater flow
Looking to find out how a comparison of feedwater flow and steam flow is made.
You're not going to be able to maintain a perfect mass balance - for 2 reasons. First, the feed...
I don't know why you feel that the flow rates cannot be compared directly as they have different...
from the Department department...Do I Understand PID's?
Just want to see if I understand these things.
A PID controller output depends on the error between the process variable PV and a target value or...
from the Proces Control department...Exe certification
Exe certification of a junction box
The best place to ask this question is with the supplier of the equipment, rather than a generic...
from the Automation List department...Android tablet for HMI?
Using an Android tablet as an all in one PLC.
You need to connect the power supply lines in the USB connection to a high-current source that can...
from the Forum department...How to replace my old EX d enclosures
When replacing old EX d enclosure, is there any problem to order new EX d enclosure and put the old components on it?
Sorry - but this advice is not correct. Under IEC rules, a bare Ex d enclosure will be certified...
from the School department...Wet Leg Pressure Level Measurement
Need assistance on Wet leg pressure level measurement situation
(There is no reason why the seal liquid should have an SG greater than the process fluid - if the...
from the Forum department...Changing Careers looking for advice
Please give me some guidelines that i am changing my careers from mechanical stream to instrumentation
As long as he doesn't take the plant with him ......
from the Forum department...Project ideas for getting into automation?
I'm learning from scratch to be an automation engineer. Where should I start?
The essential basic concepts for automation, process control, etc all reduce to one thing -...
from the Forum department...Speed of Synchronous Generator
Why Speed of Synchronous Generator decrease with increasing speed?
There is a fundamental principal in physics which is essential to grasp in control systems analysis...
from the Electrical department...Harardous Area Verification Dossier
Trying to understand Harardous Area Verification Dossier
A good starting point is IEC 60079.14 section 4.2. This lists the requirements for the dossier...
from the Instrumentation and Control department...Compensation for level measurement
compensation in level measurement for temperature
Boiler water is saturated so the temperature and pressure are related - if the pressure is known,...
from the Instrument department...Generic pressure transmitter in SIL determination
Doubts about "generic" instrument
When thinking about this, bare in mind the following ... - any laboratory-based safety...
from the electrical department...d.c.machine
doubt about relationship between speed and torque?
Torque is directly proportional to current - but speed is directly proportional to voltage. In a...
from the software department...modbus floating point format
Is it mandatory to use IEEE Format for representing floating point in 2 16bit registers?
Nothing wrong - but don't call it floating point because it isn't. What you are proposing is to...
from the Forum department...How can we produce electricity by pressure of pipelines?
I am searching about different ways to produce electricity by water.
I am searching about different ways to produce electricity by water.
Power available in watts is the product of pressure drop in Pa and the volumetric flow in m^3/s. 10...
from the Forum department...Android touch panels
Best Android touch panels with IP protection
Samsung Tab 10.1 and Asus/Google Nexus 7 both do - I'm using them as masters to control some stuff...
from the Forum department...Route to enter the industry
How to get in to the automation industry. What do I knowledge do I need and the best way get past HR / get to interview..
Debugging communications is a good example of what I meant by getting two systems to talk to each...
from the Forum department...Why 250mA fuse for 4-20mA analog input?
Why 250mA fuse for 4-20mA analog input?
25V / 250 ohms = 100 mA, so a 250 mA fuse is not going to do this job - 50 mA might....
Many 4-20 mA transmitters will pull 25 mA in the event of an internal fault, or if a seriously...
from the Forum department...Magnetizing Current
Power factor in electrical generation systems
In an electric motor, the torque is developed by the interaction between the stator current and a...
from the Forum department...Steam flow through valve
Steam flow through a valve
It depends on the valve characteristic - for a typical large turbine, the curve of flow vs opening...
from the Forum department...Temperature compensation for level sensing technique
Temperature compensation for density variation of air in hydrostatic measurement
It also undergoes a fairly rapid change in temperature if the machine is filled with cold water and...
FWIW ... I recently dismantled a discarded washing machine, mainly to get at the motor for use...
from the Forum department...Junction Boxes for zone 0
what is the minimum requirements for junction box in zone 0?
The only requirements in IEC60079.11 relating to enclosure design refer to Ingress Protection. As...
from the Department of Redundancy department...Variety of jobs in automation
Learning about different aspects of automation and gaps in learning
Profibus is a very minor technique in a very large field - I am also 66+ and have never come...
from the Forum department...Implementing PID Controller with C++
Question about how a PID Controller might be implemented in C++. How to go from continuous to discrete signal in C++?
First you need to take samples of the value to be controlled at finite intervals - the calculation...
from the Forum department...Intrinsically safe barrier required?
When are IS barriers required?
You always need some sort of energy limiter (barrier or isolator) between powered equipment and a...
from the Placing the blame. department...Risk assessment responsibility
Who is responsible for risk?
Only the final end-user can do a full risk assessment, taking into account things like the...
from the Forum department...Error of proportional only controller
Error of proportional only controller
A mathematical model of the controller is very easy - the output is proportional to the offset. In...
from the Forum department...Synchronous Generator Voltage
AC generator voltage,excitation current, voltage drop and power flow
> But this makes me think that the VARS out of the generator could be controlled by the...
Now you've got me thinking ... You're on the right track with your mental model. Unfortunately,...
There is a phenomenon in electrical systems called reactance. This applies to AC-only systems, and...
In 1750 Issac Newton became discouraged when he fell up a flight of