We currently sell electric infra red heaters that are suitable for warehouses, workshops etc. These are rated up to 230V 6kW 26A, although it is quite rare to be more than 3kW 13A. Mostly these are wired direct to the electric supply via a big switch with a heavy circuit breaker, but we do have a need for an electronic controller in a separate box between the heater and the electric supply that can do three things:
1. Switch the unit on slowly, like turning a dimmer switch. The point is that the current drawn when the heating lamps are cold is very high - this can blow some circuit breakers if you go to full power straight away. A timescale to get to full power of 3 seconds avoids the peak current.
2. Include a digital thermostat (eg via a thermister). This would save power by switching off the heaters when the room temperature is warm enough. Set point adjustment would be via a control knob. A 3 segment LED display would be provided. Normally the display would show the current room temperature, but if you turn the ajustment knob it would switch to displaying the set point and allow adjustment up or down. When the knob is released the setpoint should continue to be displayed for the next 2 seconds, then the room temperature should be displayed again. There should be a build-in offset factor of (say) 2 degrees so if the heater switches off at say 15 degrees it does not switch back on again until the temperature falls below at least 13 degrees (this avoids rapid switching around setpoint).
3. PIR - we would like to add a motion detector, with an adjustable range selection and an adjustable timer selection. The unit would only come on if motion was detected, and would stay on after that for the timer selection period (up to 10 minutes). Sensitivity and range adjustment would work in the same way as temperature, ie if you adjust the relevant control knob the display will switch to showing the setting for the relevant control until the knob has been released for 2 seconds. Then the display goes back to showing the room temperature.
A red LED next to each knob would come on when the knob was rotated, so that it was clear to the user what adjustment was being made.
Three further LEDS would show if the PIR detection was active, and if the temperature was above set point and if (based on the selection below) the unit is supplying power or not.
4. A mode control switch with 5 settings:
0 off
1 controlled by temperature only (ie on if its cold, regardless of people)
2 controlled by motion only (ie on if people present, regardless of temp)
3 controlled by temp and motion (on only if cold AND people present)
4 on (on regardless of temp or people).
If the knob is rotated the display will show the selected mode for 2 seconds (ie 0-4), then revert to the temperature display.
The unit should "remember" the settings so it will restart from last time on power up.
I assume the unit would be implemented via a small microcontroller.
We need to consider the housing that the electronics would go in and would allow the connections to be made. An industrial style is fine.
It might be better for the thermister and PIR to be remote items that connect to the box there are already off the shelf parts that can do what we need.
We probably wont have the resources to test for EMC (radio interference) but we should bear the need to avoid interference during design.
We can discuss whether to rate the unit up to 3kW only, or 4.5kW+. Depends largely on whether higher ratings are harder to do. Likewise single phase only, or three phase.
Hello, We are an Electronic Design House based in Pune, India specializing in Prototype Projects and Design Documentation. We have a strong technical team that specializes in Embedded Hardware , Firmware and PC Based Software. We bring to the table strong design and documentation skills. We can understand the design and document it as per user needs. The engineers are extremely fluent in English and working with them will not be an issue. Development work gets done in India and we have a sales team in West LA. We have an excellent network connectivity, VOIP setup for direct communication with US/European/Middle East clients. We will be able to work on this project. $750 will be charged for hardware and software design and implementation. Hardware components and PCB will be charged seperately. Work will be completed in 60 working days. Please let me know if any other information is required. Regards, Yogesh
$750 USD trong 60 ngày
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14 freelancer chào giá trung bình $586 USD cho công việc này
Hello.
We are an embedded design firm. We design, assemble, and write software for our controllers and clients.
we have several samples at www.TheSiliconHorizon.com. Note our reflow oven controllers which use a PID loop for highly accuracte temp control.
For your application we quote 600, and can be done quicker than 30 days depending on how fast the PCB's get back from china. We have china PCB contact for quality - low cost PCB's. The hardware and PCB costs are not included in our quote as this is dependant on how many units you will want (if you want us to just produce prototypes or what). We can also assemble a large number of units as we have assembly services. Thanks for considering us! -drex
Halo,
here in Zagreb, Promatis Ltd, we have good experience with heaters and high power products. If you like it I can send to your more details about our old projects that can show our references.
Regards
Zdenko pavic
Hello Dear!
I can do this project comfortably within given time as I have 5 years of experience in Microcontroller software/hardware co-design. I am 100% sure that I can deliver what you require.
Thanks
Hi ! I can design you the electronic controller for your heater that meets all of your requirements. It would be a simple, microcontroller-based device that controls the power supply to the heating elements using relays. Hence, power ratings required by you can be easily supported. ( Also there would be absolutely no difficulty with three phase systems. ) The device will also have the necessary tolerance to radio interference. With Regards, ProgramminGuru. (PS : Please provide me with a list of all the off-the-shelf parts that u have mentioned and we might find use for them. )
Long Circle is the only engineering service provider with a presence in Belmont, Massachusetts and Shanghai which provides outsourced product development service - one complete solution for hardware, firmware, software, industrial, and mechanical design, rapid-turn-prototyping, FCC/CE/CCC certificatin, and access to Made-In-China. Please check out our web site for more information.
Hello!
Less than a year ago I have developed a similar device for an industrial furnace. The device controls a 3 phase 12kW resistive heater providing variable power as required 0% to 100% with 1% step settings. The device is equipped with a LCD and a menu system for setting the mode of operation and different parameters. Temperature control is realized by PID algorithm and a programmable time-temperature profile following (the furnace is used for a very sophisticated thermal treatment of high-temperature resistant materials up to 1000 degrees Celsius). The controller is also equipped with non-volatile memory in order to resume operation in case of power supply problems etc. The controller is operated by a single knob regardless of the sophisticated menu system.
Having said that, I'll be happy to design the device that you need.
The price I offer includes design of schematics, PCB layout and software for the device. I can also provide manufacturing of the controllers if you are interested and my price is competitive.
Best regards.