Elex Quna

RTD and Connections - Mini 3W 4-20mA transmiter

2009-03-02T05:50:00.000+05:30

I´ve been looking at the mini-three wire 4-20mA transmiter and it is everything I need to try a new way of measuring the temperature. It is great but there are a few questions about it I hope you can answer them:

- What is the meaning of RYIN and RXIN?
- You say that it is a three wire circuit but I can only seen two points of connection for the PT100. Is it because the signal conditioner of the three wire PT100 isn´t drawing?
- The OUTPUT connector is where I can find the 4-20 mA?

I hope there is no problem to answer these quetions to me, I would be really pleased if you can do it and I´d appreciate it.

Many thanks and hope to hear soon from you.

Mail from AD - Spain

All the transmitter circuits can be seen here. Industrial Process Control Circuits

As this circuit was popular i have made a separate page for it. Mini RTD Pt-100 Three Wire Transmitter

A ex-customer of mine, (ex because i don't manufacture now.) wanted a low cost transmitter, so i made this.

What is the meaning of RYIN and RXIN? - Connect it to any two wire RTD

For RTD read more RTD Omega - RTD Intro

You say that it is a three wire circuit ....

+V .... -V .....OUTPUT ...... on the left are the three wires.

+V and -V is the Supply. OUTPUT is a Current Sink Directly Proportional to Temperature on RTD.

In the Costlier 2 Wire systems, Current Drawn by Transmitter is Directly Proportional to Temperature on RTD. Two wire systems can be just looped, 3 Wire like mine has to be wired, more wire.

The OUTPUT actually drinks 4-20mA prop to Temp. Put a Ammeter (fused) in 0.2A range in Series with a 50 Ohm Resistor. Black Lead of ammeter to this OUTPUT. Red Lead to one end of 50 Ohm. The other End of 50 E to +V.

delabs

Thank you for your quick answer. I think I´ve got it. Although there is another question that has come up to me while reading your email. +V and -V is the supply I apply to the PT100? I am applying 24DCV so I suppose the +V is the 24V and -V is the ground, isn´t it?

Reply from AD - Spain

YES - +V is the 24V and -V is the ground, anything above 12V will work.

The 24 V should be applied to +V and -V only. Not to RTD Directly. RTD Directly Connected to 24V will BURN the RTD.

RTD is a Thin Platinum Film or Wire of 100 Ohms worth. The Resistance varies with temperature.

A 1mA ONLY Constant Current is sent thru the RTD to measure the Voltage across it. From the measured voltage 100mV for the 100 Ohms is subtracted using opamps.

The balance mV is Directly Proportional to Temperature. This mV is converted to 4-20 mA. 4-20 mA is a Strong Signal for Current Loop Transmission.

4mA is 0% 12mA is 50% and 20mA is 100% of the range you calibrated.

delabs

Related Reading

Electro tech online - Design Forum

2009-02-18T10:16:00.000+05:30

Electro tech online - Design Forum

Electronic Projects Design/Ideas/Reviews
Are you building an electronic project or want to? Maybe you need some assistance? Come and submit your electronic questions here and let our exprienced members find a solution.

Micro Controllers
Discuss all aspects of micro controllers - building them, coding them, etc. All controllers are welcome - PIC, BASIC, Z8 Encore!, etc.

Battery Management and Supply Design

2008-11-22T18:20:00.000+05:30

Continued from uC Board is Misbehaving on Brown Out

Read articles in the link you provided, thanks for that!

As you have have pointed out, my circuit is not driving any motor or such loads...but it is driving a WIRELESS MODULE which draws about 165mA to 240mA from my circuit during transmission[for 4 sec] and normally it takes upto 114mA. After a time-out of 1min, I put my uC P89V51RD2 to powerdown mode[200uA in this state].

My other problem is that my batteries get supercharged upto 5.8V, and as per spec's of most IC' they are bound to operate faithfully upto 5.25[max 5.5v], so how do I solve this issue? I want that my boards get only 5.25v even if my battery is having voltages 5.25+, without increasing my existing current consumption to noticeable value.

Moreover I'm in need of a cutt-off circuit which will take away the load from my batteries when my battery has reached 4.00V, & the charger charges my battery independently. Do you have any thing which will suite my purpose?

Mail from MO

Have two supplies, the one for uC can be a small Ni-Cad battery charged by a diode by the bigger battery which supplies the 200mA for RF drivers.

So when the big battery is loaded and the supply dips the shock is not felt by uC. or isolate it by SMPS and isolate the grounds. The ground return current of RF module 200mA must be lifting the ground of uC or some Logic.

Start by trying to locate the problem, first power RF and uC boards with isolated lines from two lab-test 10A power supplies. If both are in same board, cut tracks and power them separately. The grounds should meet at point the two sections interface.

If that works without problem, you know it is related to supply, now step-by-step go back to the battery and charger you have built keeping isolation intact. Look for spikes-glitches on power lines of uF when RF module active. Check if that is close to or leaking RF to uC circuits.

The battery charger circuit should limit voltage and current to battery specs. If you are not using a charger chip then while testing make sure the charger has a regulator or use LM317 to clamp voltage to 5.6 or 5.5 as per your design.

There are charger chips from maxim, national for battery charge management. If you have a need for extra voltage the you have to use SMPS boost switcher. which may take the low battery 4 to 8 which can be regulated to 5 using 7805.

This may be getting bit complex, first try to find what is the problem, it may be just the board design.

delabs

Binary ASK modem - Power line Modem

2008-11-21T21:44:00.000+05:30

Want hlp in dsigning of a binary ASK modem or Power Line Modem.

Mail from AM UK

Study these links ....

delabs

How to Connect RTD to transmitter

2008-11-16T11:20:00.000+05:30

Can you explain me were i have to conect the three cables of the PT100 in the Circuit RTD-Pt-100-Transmitter Circuit?

RTD PT100 Transmitter and Multiplexer

Comment from CV of Spain

You have a three wire RTD there are even 4 wire RTD, This circuit can be used for both.

In the 3W RTD you have two wires coming from the same point (zero ohms between them) the third wire will be 100 ohms from these two. From the two wires that are at same point take one wire and give 1mA from Q3 + OUT. The other wire of the pair connect to input +..... input - can be connected to the 100E end.

Learn more

delabs

So imagine that I have three wires one white and two blacks.

One black to +OUT 1ma
Other black to input-

And waht about the withe one that is the one that give me arround 100ohms??

Reply from CV

Black 1 - +Out 1mA
Black 2 - +Input
--------------
White goes to -Input

See NI Developer Zone - RTD Connections

delabs

Leakage of SSR driving AC Solenoid

2008-09-18T09:15:00.000+05:30

message: I have a 115vac ssr powering a solenoid only pulling a 160ma. upon activation 115vac is applied, but upon deactivation 78vac is still present. I'm told I need a bleeder resistor, but no one knows exactly what size? Can you help?

Mail from GH USA

When a solenoid draws 160mA, you dont need a bleeder. That itself is a bleeder. The leakage of the ssr is very less, it is mainly the current thru the snubber caps.

The SSR cannot leak so much, Is the solenoid a simple coil solenoid or has circuitry? A coil solenoid is also a bleeder for the 1 or 2mA max AC current from caps.

If the solenoid has some control circuit then you may need a bleeder, put a 100K 250V 1W. It also could be a defective SSR or a NC (normally closed) SSR with improper control signal.

Check if control and load circuits are isolated too, make careful measurements across the ssr. Tell me if you still are in doubt,

delabs

Sourcing the SP646 Solid State Relay

2008-08-19T20:48:00.000+05:30

I have a customer that call out a Solid State relay and i cannot find any information on it. Can you help? It is a SP-646. I need a quote on 60 and 120 pieces.

Mail from PG US

Have a look at this, is this what you want. SP646 1 Form A Solid State Relay. contact them if the specs are right, ssousa.com -contact

Description

The SP646 is a bi-directional, single-pole, single-throw, normally open multipurpose relay. The circuit is composed of one LED on the input side which activates an optically coupled IC on the output - controlling the firing angle of two back-to-back SCRs. This circuit assures no false triggering under most adverse conditions, and a tight zero-volt window not exceeding 5V.

Features

Inverse parallel SCR output
High transient immunity
400V blocking voltage
1.2A maximum continuous current
Low input control current
High input-to-output isolation
Solid state reliability
Zero-volt switching

Applications

Programmable controls, Valve control, Solenoids, Remote switching, Home appliances, Metering equipment, Heating elements, Gas pump control circuitry,

The SP646 Data Sheet includes the Complete Overview, Electrical Characteristics, and Schematic Diagrams.

Even if you dont find the same number, Digikey or Mouser may have an Equivalent. Just match the Electrical Specs and PCB Footprint, pitch etc.

mouser - digikey - jameco see list here Components Suppliers

delabs

Three Phase AC SSR for 1 HP Motor

2008-08-19T16:33:00.000+05:30

I need to build a three phase AC(in 120V)-AC(out 440V) solid state relay to turn on or off a small(1hp) three phase AC motor. Do you have any idea?

Can I use three MOC3043 and three TIC236E triacs of course with all opto LEDs in series?

Mail from FJP Brazil

See my SSR Circuits , Solid State Relays or SSR Choose a DC Control and AC Load SSR, That is what you seem to indicate.

1 hp = 745.699872 watts

Let triac have 10 A and 600V AC ratings, BTA12600 But now BTA12600 is obsolete, adapt to what is available in your country.

MOC3043 is fine, isolation must be good, take care. Use a Heatsink.

ON-OFF Control inputs can be parallel not series.

On this page you can see a 3 phase SSR i built. Three-Phase-SSR.

delabs

Hypersonic Speakers - Acoustic Heterodyning

2008-08-19T08:50:00.000+05:30

i have been searching for any technical help regarding my project, hypersonic speakers,but my efforts were in vain. hypersonic speakers are instresting to work upon. kindly guide if if you have any knowledge regarding the topic

Mail from GA

See these links ...

Hypersonic Sound: Sound From Thin Air - Mix two signals in a nonlinear medium and you'll end up with four - two at the original frequencies....

Hypersonic Sound speakers are like Invisible headphones.

Sound technology turns the way you hear on its ear - Woody Norris, inventor of ultrasound technology,

Acoustical Society of America Lay Paper on Hypersonic Sound: -

HyperSonic Sound HSS from American Technology Corporation employs ultrasonics to create audible sound in the air. It works by using harmless ultrasonic tones that we can't hear

delabs

Thanks for your reply for hypersonic speakers , but sir i am unable to have any positive feed backs as far as its making is concerned, i have contacted hypersonic industries also in this context, but they want me to buy a unit. i will see what i can do. thank you once again for your help.

Reply from GA

I dont know if this idea is good for college projects, but you can buy a Hypersonic Speaker and demonstrate an application in automation.

delabs

Search Forums and FAQ Resources

2008-08-12T09:41:00.000+05:30

You may find Answers to your Questions below, Use below Resources, you can then contact me too,. Start a New Topic.

Lead Acid Batteries FAQ

2008-08-07T21:50:00.000+05:30

Some Questions, Searches about Batteries Answers Below, My Collection of Website Resources.

delabs

Te Lead Acid Batteries are used in Automobiles and UPS - Uninterrupted Power Supplies. Battery Banks and Arrays are used in Home and Industrial Power Systems with Solar and Wind power charging too. Chargers & Charging -- Battery Management

These batteries have survived many other types, for rugged high power usage, even beyond 100Kva. It is all the more important for us, to learn how to use them properly. Intelligent charge controllers and charge-discharge cycle regulating managers, will ensure a long lifespan for optimum cost-effective usage of this Electro-Chemical Wonder.

Digital Counter - 4029 and 4511

2008-06-24T12:19:00.000+05:30

I just about the circuit you made. what kind of IC is 4029N & 4511N? Is it a diver/decoder? I tried to research on the datasheet but it cannot give exact specification...

Mail from JT from Philippines

4029 is a Preset Dec-hex, up-dn, Counter - and 4511 is a 7-Segment Display decoder. Learn more see ....

Word doc and exe attachments i don't open. send a jpeg photo or rtf or pdf or prepare your doc online Google Docs. please also tell me which page or circuit is this question about. any other doubts feel free to ask. Is it this ... Simple Digital Counter - doc00021

delabs

yes, .thanx for the links..i'll try to go over with the theory..so where can we purchase those items if ever we need it?

Reply from JT

It depends on which country you are in see this page Components Materials

delabs

Halogen bulb lamp dimmer circuit

2008-06-19T16:15:00.000+05:30

Can someone provide me a (simple) schematic for a dimmer that would control 12 VAC about 80 watts. This would be used to control a lamp with halogen bulbs.

Anonymous in Hobby Hound

Here is a listing study them and choose, try out, learn and then build the one right for you.

delabs

Bioamp for muscle signals - EMG

2008-06-18T13:24:00.000+05:30

message: I'm working an a bioamp for muscle signals. This is the base design, but it does not work. Basically what I want to do is a circuit that amplifies my muscle signals and is able to run a small dc motor when I flex a muscle. Any help? Thanks

Mail from JX US

Study these links and send me a feedback ....

delabs

SCADA System - Project Idea

2008-06-12T21:45:00.000+05:30

Hello Sir, I am a student of Electronics and Instrumentation Branch from BP. I am doing my training at ..... where i have been assigned a project to implement SCADA System using Microcontroller.

Right now,i have a good knowledge of PSOC and AVR microcontrollers but since i am new to this technology,i am not getting how i should proceed for the project.i would be greatful to you if you can provide some information about the previous projects students have done in you organization regarding scada implementation.

Mail from MG India

A "SCADA System" may consist of a Human using a Computer with Special Software Overseeing a Process Control System made of many sensors, transmitters, autonomous controllers and actuators made of motor drives and heaters.

Some of these elements may send data to the computer which may Analyze and Indicate the condition of process or progress. The Human Operator can then fine tune the parameters of his system or study and record process cycles for quality and yield.

You discuss this with your mentor and then build a part of it, or implement a part of it in an existing system. A whole SCADA system is too big a project, but a simulated or demo software interface project can be made.

Try seaching at Google Scholar also study links below.

This will be posted to Elex Quna, comment on that post to continue. Any other doubt post as a comment, I will Answer it.

delabs

Using LEDs with Battery Power

2008-05-08T14:28:00.000+05:30

What are LEDs ? How can we use them for Long Battery Life

Mail from AD

If LED flashes at 5-10 K Hz at even 50% Duty Cycle. It may save some power and improve life. So it is just an idea, it may not solve the problem. The idea was to improve battery life and give uniform light for annunciators. It may not be good for flashlights.

delabs

LF353 - Wide Bandwidth Dual JFET

2008-05-08T10:52:00.000+05:30

LF353 - Wide Bandwidth Dual JFET

These devices are low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage (BI-FET II™ technology). They require low supply current yet maintain a large gain bandwidth product and fast slew rate. In addition, well matched high voltage JFET input devices provide very low input bias and offset currents.

(Google Talk Transcript - Year 2006 )

TF (12:16:46 PM): i need a clarification on OpAmp
delabs (12:16:57 PM): ok tell me
TF (12:20:55 PM): what parameter should I check to know the frequency response of an Opamp
TF (12:20:55 PM): the thing is i am reading about a perfect rectifier
TF (12:20:55 PM): so i am trying to find out how to get its maximum frequency
delabs (12:21:14 PM): ok
delabs (12:22:02 PM): you mean precision rectifier
TF (12:48:56 PM): are u there sir
delabs (12:49:17 PM): national.com/mpf/LF/LF353.html
delabs (12:49:03 PM): These devices are low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage. They require low supply current yet maintain a large gain bandwidth product and fast slew rate. In addition, well matched high voltage JFET input devices provide very low input bias and offset currents. The LF353 is pin compatible with the standard LM1558 allowing designers to immediately upgrade the overall performance of existing LM1558 and LM358 designs. These amplifiers may be used in applications such as high speed integrators, fast D/A converters, sample and hold circuits and many other circuits requiring low input offset voltage, low input bias current, high input impedance, high slew rate and wide bandwidth.
delabs (12:50:16 PM): Characteristics of Operational Amplifiers
TF (12:52:03 PM): checking
TF (12:52:26 PM): i think slew rate would be the parameter
delabs (12:52:42 PM): great, you got it

(Links modified as educatorscorner.com has moved here Agilent - Educator's Corner, use search 'slew')

Insulation Resistance Analyzer Required

2008-03-31T21:22:00.001+05:30

Please quote for Insulation Resistance Analyzer DRT101
with regards...

Mail from AT India

delabs is a website for education of engineers and hobbyists . The photos and documents are products that i used to make years back. I do not manufacture now. The circuits and photos are to give ideas for youngsters and entrepreneurs.

Please search India Mart , that will help. I just found one Motwane Insulation Tester - D2K

delabs

If anyone wants to quote a Insulation tester to AT, start by commenting on this post with an OpenID.

Logic Analyzer on Computer

2008-03-23T15:36:00.001+05:30

The following was submitted on March 8th, 2008 at 06:47AM (CST).
HiQFormMail version 1.5.1 - delabs.net - paysource

Subject: delabs Schematic Source Request.
Circuit: del20006.pdf
Title: Test circuit for Logic Analyzer
Message: I am a retired hobbyist.

Mail from JL USA

Sorry for the late reply, Can you explain in detail your doubt or problem. Meanwhile Have a look at these circuits

delabs

I am interested in obtaining a copy of the file "Logic.zip" referred to in the article. PC-Based Logic Analyzer (below). The link to the file is not available. The file contains the software for the circuit described.

Reply from JL

If anyone wants to interact with JL, start by commenting on this post with an OpenID.

These books may help learn Interfacing Your Designs to a PC.

Parallel Port Complete: Programming, Interfacing & Using the PC'S Parallel Printer Port by Jan Axelson

USB Complete: Everything You Need to Develop Custom USB Peripherals (Complete Guides series) by Jan Axelson

Room Temperature Monitor and Alarm

2008-03-17T12:28:00.000+05:30

I am required to design an electronic system that monitors the temperature between(22-24 degrees Celsius). Given are power supply, Analogue subsystems and digital subsystems. the accuracy of the digital control circuit is limited by the accuracy of the temperature sensors. A green LED is lit to indicate correct temp range.

A red LED indicates out of range temperature and in sustained events( where this indicates out of range temp which is counted, displayed and timed) a large LED is lit. In a event where the sustained event exceeds 6 days an alarm is sounded to indicate a possibility of a system failure.

Now I need help on how to come up with the correct circuit diagrams which can work , how to simulate and to get the project done, please help, even direct me to books on the project or other sites please...

Mail from AM South Africa

First acquire the room temperature as an analog value. This requires a sensor for the range you indicated a Semiconductor sensor like LM335 will do fine.

Now monitor and generate Logic outputs for temperatures out of range using a Window Comparator. Then for the timed events you need a Timer circuit. And a Logic to set off the Alarm or Annunciator.

All this can also be done by a PIC circuit if you can write some code. I have given some pages to see, study them, that will be sufficient

delabs

Orcad Spice Simulation CD4060

2008-03-16T20:48:00.000+05:30

I found your web site today. I am looking for the CD4060 spice model for Orcad Capture. My Orcad version is the 9.2 (complete but without CD4060 !!)

I saw on your web pages a design using this component. How can I have the CD4060 model (to use it in simulation) ?

Mail from EG France

Have a look at these links.

PSPICE 9.1 student version - electronics-lab.com-downloads-013
see the database library files.

"The Orcad demonstration package includes several libraries for circuit layout, but only the EVAL.LIB has SPICE models as well. This library includes a range ...."

Please study all links above and tell me if it solves your problem, Look and study each link above. If you have a problem still, then i will search again or find a solution

Also try out and use Cadsoft Eagle.

delabs

Application for 8051 mcu project

2008-03-12T16:56:00.001+05:30

Unique Application for 8051 mcu project ?

Post by J9

Look at this place

8052.com - The Online 8052 Resource
Atmel Products - Microcontrollers - 8051
8051 Microcontroller and rentron.
The best place is PJRC: Electronic Projects
Amazing place here Build Your Own Microcontroller Projects at Thailand.
8051 Sourcecode
SDCC - Small Device C Compiler
Circuit Cellar Ink 151
Sam's 8051 Page
Microcontroller Beginner Kit

delabs

This is an answer of mine to an old post - 2006

How does RTD Work

2008-03-12T13:42:00.001+05:30

How Resistance temperature detector works?

Post by JG

The most popular RTD is PT-100, Platinum 100 Ohms, As all Metals have a Temperature Coefficient of Resistance. The Resistance of RTD increases with rise in temperature.

Even Copper wire can be used, but you need to have a very thin and long wire to make usable measurements.

delabs

This is an answer of mine to an old post - 2006

Build RFID transmitter and receiver

2008-03-11T21:05:00.001+05:30

Guide on how to build my own RFID transmitter and receiver?

Post by C1

You will find them here ...

delabs

This is an answer of mine to an old post - Tuesday 27 June 2006 22:34

Continuity Tester

2008-02-27T19:09:00.001+05:30

Question - continuity tester circuit