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Control.com member...
Member Information and Posts by BruceD
Originally posted by RLovell on 29 August, 2014 - 1:08 pm
My high school students ask when/how/if abstract topics like polynomials, factoring, rational functions are ever actually used in the Real World. I don't know..maybe you do?
New Replies:
The behaviour of a car's suspension system - in terms of bounce period and damping - are given by...
Topic: Engineering and workplace issues.
from the Forum department...
Customized Control System ExD Enclosure
Originally posted by Rashid on 27 August, 2014 - 12:46 am
We have procured a Customized PLC ExD Enclosure.

New Replies:
Check the certificate number of the enclosure as supplied. If it has a suffix -U, this indicates...
Topic: Engineering and workplace issues.
from the automation department...
Difference Between Full Load and Rated Conditions
Originally posted by winds_977 on 21 August, 2014 - 11:59 am
Confused between the terms full load and rated conditions.
New Replies:
For a pump driven by an electric motor, the rated voltage of the motor is the nominal value of the...
Topic: Engineering and workplace issues.
from the Electrical department...
Generator capacity
Originally posted by Not applicable on 29 June, 2014 - 3:54 am
Calculation of capacity of generator.
New Replies:
Since the rating of a generator is expressed in terms of power, with a base of watts, and you have...
Topic: Power generation equipment control.
from the Forum department...
Different modes of AVR operation
Originally posted by ASHISH on 20 April, 2012 - 1:11 pm
Brush AVR A-30 different modes of operation?
New Replies:
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...
Topic: Power generation equipment control.
from the Forum department...
Excitation system
Originally posted by bing on 10 May, 2009 - 12:50 pm
What is an excitation system is and what role it does play in the start up of a prime mover like a gas turbine
New Replies:
What else happens at the same time? If by "island mode" you mean that your plant is...
Topic: PLCs and related questions.
from the Advice for a newb department...
Modbus "pollsets"
Originally posted by GD on 5 June, 2014 - 6:27 pm
Need advice on creating pollsets in Isagraf
New Replies:
Why do you need to use 3xxxx registers? These are "read-only" as they are set by the...
Originally posted by Alphite on 28 May, 2014 - 4:25 pm
How to control flowrate and pressure with a positive displacement pump.
New Replies:
A positive displacement pump is essentially a constant-flow device, with discharge pressure...
Topic: Power generation equipment control.
from the Electrical Power Engineering department...
Power System Control & Stability
Originally posted by Asif Ferdoush on 22 May, 2014 - 1:31 pm
What happens when power system is subjected to any kind of disturbance?
New Replies:
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...
Topic: Continuous process industries, DCS questions.
from the Maintenance department...
Endress+Hauser Level Transmitter Hunting
Originally posted by Talluri on 21 May, 2014 - 2:59 am
What is the possible cause for Level transmitter hunting?
New Replies:
One possible reason for a level loop being reported as "hunting" is a phenomenon called...
Topic: PLCs and related questions.
from the The Unknown Entity department...
One control variable for two loops
Originally posted by TheController on 15 May, 2014 - 5:21 pm
Can we have one control variable control two different loops?
New Replies:
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...
Originally posted by PT on 6 May, 2014 - 5:23 am
Reading IEEE little endian format data
New Replies:
Are here any values in the system that are in a known range? I'm thinking something like base...
Topic: Engineering and workplace issues.
from the Safety department...
EEx 'd' or IS
Originally posted by MJ on 1 May, 2014 - 6:43 am
What are the criteria in deciding between EEx 'd'/'e' and Intrinsically Safe?
New Replies:
If it's mandatory to use all Zone 0 instrumentation, the Ex ia is your ONLY option - Ex d is not...
Originally posted by Danish on 29 April, 2014 - 4:43 pm
220 KV transmission line safe distance from the Gas vent tower.
New Replies:
The installation standard for Australia and New Zealand AS/NZS 60079.14 (modified from IEC...
Topic: Continuous process industries, DCS questions.
from the Forum department...
Comparing steam flow and feedwater flow
Originally posted by MattQ on 27 April, 2014 - 2:33 pm
Looking to find out how a comparison of feedwater flow and steam flow is made.
New Replies:
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...
Topic: Continuous process industries, DCS questions.
from the Department department...
Do I Understand PID's?
Originally posted by Piedon on 17 April, 2014 - 9:58 pm
Just want to see if I understand these things.
New Replies:
A PID controller output depends on the error between the process variable PV and a target value or...
Topic: Engineering and workplace issues.
from the Proces Control department...
Exe certification
Originally posted by Sumesh on 1 April, 2014 - 3:13 am
Exe certification of a junction box
New Replies:
The best place to ask this question is with the supplier of the equipment, rather than a generic...
Topic: Human-Machine Interface and SCADA.
from the Automation List department...
Android tablet for HMI?
Originally posted by Ken E on 3 June, 2011 - 11:18 am
Using an Android tablet as an all in one PLC.
New Replies:
You need to connect the power supply lines in the USB connection to a high-current source that can...
Topic: Engineering and workplace issues.
from the Forum department...
How to replace my old EX d enclosures
Originally posted by Ibrahim Abdelmohsen on 6 January, 2014 - 6:01 am
When replacing old EX d enclosure, is there any problem to order new EX d enclosure and put the old components on it?
New Replies:
Sorry - but this advice is not correct. Under IEC rules, a bare Ex d enclosure will be certified...
Topic: Information resources, documentation.
from the School department...
Wet Leg Pressure Level Measurement
Originally posted by Jerry on 15 March, 2014 - 8:29 pm
Need assistance on Wet leg pressure level measurement situation
New Replies:
(There is no reason why the seal liquid should have an SG greater than the process fluid - if the...
Topic: Power generation equipment control.
from the Forum department...
Changing Careers looking for advice
Originally posted by surya on 10 February, 2014 - 6:28 am
Please give me some guidelines that i am changing my careers from mechanical stream to instrumentation
New Replies:
As long as he doesn't take the plant with him ......
Topic: PLCs and related questions.
from the Forum department...
Project ideas for getting into automation?
Originally posted by Rhonage on 15 February, 2014 - 9:59 pm
I'm learning from scratch to be an automation engineer. Where should I start?
New Replies:
The essential basic concepts for automation, process control, etc all reduce to one thing -...
Topic: Power generation equipment control.
from the Forum department...
Speed of Synchronous Generator
Originally posted by Muhammad Salman on 26 February, 2010 - 4:08 pm
Why Speed of Synchronous Generator decrease with increasing speed?
New Replies:
There is a fundamental principal in physics which is essential to grasp in control systems analysis...
Topic: Engineering and workplace issues.
from the Electrical department...
Harardous Area Verification Dossier
Originally posted by Biky on 2 February, 2014 - 11:53 pm
Trying to understand Harardous Area Verification Dossier
New Replies:
A good starting point is IEC 60079.14 section 4.2. This lists the requirements for the dossier...
Topic: Engineering and workplace issues.
from the Instrumentation and Control department...
Compensation for level measurement
Originally posted by bhargav purohit on 20 January, 2014 - 8:52 am
compensation in level measurement for temperature
New Replies:
Boiler water is saturated so the temperature and pressure are related - if the pressure is known,...
Topic: Engineering and workplace issues.
from the Instrument department...
Generic pressure transmitter in SIL determination
Originally posted by Ricardo Almarza on 14 August, 2009 - 2:59 pm
Doubts about "generic" instrument
New Replies:
When thinking about this, bare in mind the following ... - any laboratory-based safety...
Topic: Engineering and workplace issues.
from the electrical department...
d.c.machine
Originally posted by electrical on 26 December, 2013 - 7:04 am
doubt about relationship between speed and torque?
New Replies:
Torque is directly proportional to current - but speed is directly proportional to voltage. In a...
Topic: Software, including programming, OS issues, etc.
from the software department...
modbus floating point format
Originally posted by mbusland on 21 December, 2013 - 9:34 pm
Is it mandatory to use IEEE Format for representing floating point in 2 16bit registers?
New Replies:
Nothing wrong - but don't call it floating point because it isn't. What you are proposing is to...
Originally posted by Maryam on 14 December, 2013 - 9:51 am
Hi
I am searching about different ways to produce electricity by water.
New Replies:
Power available in watts is the product of pressure drop in Pa and the volumetric flow in m^3/s. 10...
Topic: Application Questions and Problems
from the Forum department...
Android touch panels
Originally posted by dex on 13 June, 2013 - 8:52 am
Best Android touch panels with IP protection
New Replies:
Samsung Tab 10.1 and Asus/Google Nexus 7 both do - I'm using them as masters to control some stuff...
Topic: Information resources, documentation.
from the Forum department...
Route to enter the industry
Originally posted by Jimmy on 5 June, 2013 - 5:06 pm
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..
New Replies:
Debugging communications is a good example of what I meant by getting two systems to talk to each...
Topic: PLCs and related questions.
from the Forum department...
Why 250mA fuse for 4-20mA analog input?
Originally posted by Mohamad Ashour on 9 May, 2013 - 5:31 pm
Why 250mA fuse for 4-20mA analog input?
New Replies:
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...
Topic: Power generation equipment control.
from the Forum department...
Magnetizing Current
Originally posted by Noel Brady on 3 May, 2013 - 1:26 pm
Power factor in electrical generation systems
New Replies:
In an electric motor, the torque is developed by the interaction between the stator current and a...
Topic: Information resources, documentation.
from the Forum department...
Steam flow through valve
Originally posted by engineer on 24 April, 2013 - 10:45 am
Steam flow through a valve
New Replies:
It depends on the valve characteristic - for a typical large turbine, the curve of flow vs opening...
Originally posted by praveen on 7 April, 2013 - 3:35 pm
Temperature compensation for density variation of air in hydrostatic measurement
New Replies:
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...
Topic: Engineering and workplace issues.
from the Forum department...
Junction Boxes for zone 0
Originally posted by Ibrahim Abdelmohsen on 27 March, 2013 - 7:16 am
what is the minimum requirements for junction box in zone 0?
New Replies:
The only requirements in IEC60079.11 relating to enclosure design refer to Ingress Protection. As...
Topic: Information resources, documentation.
from the Department of Redundancy department...
Variety of jobs in automation
Originally posted by MC on 14 March, 2013 - 10:30 am
Learning about different aspects of automation and gaps in learning
New Replies:
Profibus is a very minor technique in a very large field - I am also 66+ and have never come...
Topic: Engineering and workplace issues.
from the Forum department...
Implementing PID Controller with C++
Originally posted by tvlas on 6 March, 2013 - 3:28 am
Question about how a PID Controller might be implemented in C++. How to go from continuous to discrete signal in C++?
New Replies:
First you need to take samples of the value to be controlled at finite intervals - the calculation...
Topic: Engineering and workplace issues.
from the Forum department...
Intrinsically safe barrier required?
Originally posted by Jordan on 21 February, 2013 - 6:22 pm
When are IS barriers required?
New Replies:
You always need some sort of energy limiter (barrier or isolator) between powered equipment and a...
Topic: Application Questions and Problems
from the Placing the blame. department...
Risk assessment responsibility
Originally posted by Tom Bullock on 19 February, 2013 - 10:34 am
Who is responsible for risk?
New Replies:
Only the final end-user can do a full risk assessment, taking into account things like the...
Topic: PLCs and related questions.
from the Forum department...
Error of proportional only controller
Originally posted by Asad Khan on 10 February, 2013 - 10:23 am
Error of proportional only controller
New Replies:
A mathematical model of the controller is very easy - the output is proportional to the offset. In...
Topic: Power generation equipment control.
from the Forum department...
Synchronous Generator Voltage
Originally posted by Rudy on 12 February, 2013 - 11:50 am
AC generator voltage,excitation current, voltage drop and power flow
New Replies:
> 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,...
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