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Tuesday, June 25, 2019

Sequential Timer Design

I’m working on a small electronics project but don’t know too much about designing circuits so I figure I would ask someone who knows and this seems like the place. Ok,

What I’m looking for is the following: I need a circuit that when the switch is pressed it will close the circuit and in an adjustable amount of time via adjustment knob: I’m not sure what the name of the adjustment component is called but its: (A small box shaped component that can be adjusted using a small screw driver. In a circular clockwise motion to speed up the time and counter-clockwise to slow it down) a solenoid will actuate and move in the forwards direction....

 See entire thread here Two Stage Sequential Timer - del90004

Two Stage Sequential Timer
Mail from RH  USA 2004

This is an example of a cascaded or sequential timer, here two CD4541 are forming a two stage timer. You can add more in a chain, but better to use a microprocessor or Microcontroller for such a purpose.

The circuit is a two stage sequential timer with auto reset. It can turn a Solenoid On/Off after a Sequence of delays that are preset. This is also a basic example of timer usage in automation.

All Timers are 1 - 30 Secs Analog with Presets to adjust with a screwdriver. The Switch, Solenoids and Power supply has to be via terminal blocks or plug-jacks. The PCB may be upto six Square Inches for standard DIP components but with SMD it may be smaller.


Monday, June 24, 2019

Timer and Counter for RTD System

Thank you for your assistance. My answers are by your questions.

Hope this helps. This unit is more for troubleshooting a air flow problem. If the counter shows many 130 Degrees detected or alarm is going off several times a higher priced system for a forced air flow will be needed. Currently no way to detect heat increases going around vent so client doesn't want to purchase forced air flow system. This is a safety device so client can decide on this cheaper system to monitor or a more expensive permanent fix. I will need a PCB setup after I can test the circuit in test environment.

Mail from NV 2004

The temperature in a pipe is monitored with four RTD Pt-100 Sensors, The type of probe could be Extruder RTD probes with Bayonet or Compression Fitting, Get it from Omega. The temperature at four points are measured by Temperature Module and compared with one setpoint 0-200 deg C, an alarm output LED out-a goes ON when the measured temperature exceeds the common setpoint.

Timer and Counter Modules - del90002

Timer and Counter Modules
Pan and Zoom the Circuit for detailed Study here - Timer Counter for RTD

a. do you need individual setpoints for all the four points you measure ? - NO

b. is the temperature deg C or deg F, centigrade or Fahrenheit ? - 130 F

c. do you need a relay output when the LED goes ON to turn off the heater ? NO

d. the time taken to measure 4 points will be 4 seconds is that fast enough ? YES

e. do you need a display of the measured temperature as shown above ? NO

The Analog Timer Module can be set from 0- 30 minutes. If out-a remains high even after set time a out-b alarm goes on with a relay output, the relay contacts can be used to turn off a heater or sound a buzzer.

a. do you want to use a digital timer instead ? - I'm open. Trying to keep costs down

b. do you need a solid state relay output ? - Used like a smoke detector. Alarm to notify client to check air flow. This is in case the air flow stops.

Mail from NV 2004

Saturday, June 22, 2019

Temperature with Timer Triggers Counter

I'm looking at an idea for a circuit design; The idea is to sense a temp of 130 degrees and then light an LED and start a timer delay. The delay would be 3 min, after the delay if the temp is still above 130 sound alarm.

With the LED I would like to drive a counter display to show how many times the temp was sensed. I would like powered by 120vac and a 9 volt battery backup for counter circuit.

If you can assist please let me know.

Mail from NV USA 2004

The circuit you require is possible, what is the time frame within which you require it ? You also need to tell the resolution you require is it 130 or 130.0 and counter upto 9999 ? what are the controls you want and the outputs required if any.

I can design above with simple analog-digital based circuits, microcontroller based designs will
take much more time but can be upgraded easily.

Four Channel Temperature Alarm

Reply from delabs

Temperature with Timer Triggers Counter
Pan and Zoom the Circuit for detailed Study here - Pt-100 RTD Four Point Alarm

130 1%, at least 0-999...

a reset for counter and I would like the temp sensor to have 4 sensors so I could surrond a pipe and any sensor would trigger circuit. The unit would be mounted about 6-8 inches away from sensors. Thinks a probe type sensor so it can protrude from a plastic tube that wil be sheped to meet pipe or vent design.

I might not need AC if the circuit can be powered from 9 VDC battery like a Smoke detector.

Mail from NV