57 lines
2.2 KiB
Markdown
57 lines
2.2 KiB
Markdown
---
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title: "Saike 858D++ - First Block Diagram"
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date: 2018-07-10T10:45:00+02:00
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author: eNBeWe
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type: post
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categories:
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- Allgemein
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- Bastelkram
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tags:
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- 858D
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- DIY
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- Arduino
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---
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After a short break, here is the first part about the redesign of the Saike 858D rework station ([Overview][1]).
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Let's talk about a rough block diagram for the new design.
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<!--more-->
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[](/posts/images/858D/Concept-New-Design_V1-big.png)
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Let's have a look at the general structure and first follow the path of the power supplies.
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Twe build a mains powered device so we start with that at the top left.
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The mains power is fed into the heater control circuit as well as a 24V switch mode power supply,
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which I will use to replace the transformer.
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The 24V power supply is connected to the fan control circuit and another switch mode supply,
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this time providing a 5V rail.
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The 5V supply is used for an Arduino board,
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which will be plugged on the main PCB. I have not yet decided which model I want to use,
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but it will probably be one of the Pro Micro or Nano boards I have lying around.
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Additionally, the 5V supply is used for the other logic level components,
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like the display and the sensors.
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The Arduino is connected to the heater and fan control circuits,
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both regulated through some form of PWM.
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The heater control will use more or less the same design as the original,
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regulating the heater through a optocoupled triac.
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The fan control will use regular PWM to switch a power mosfet that
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can in turn regulate the fan supply.
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Additionally, there will be a form of monitoring of the fan speed.
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I am currently pondering which way I want to go there.
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The display will be replaced by two 7-segment displays with 4 digits each.
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The displays are controlled by a MAX7219 IC,
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which is connected to the Arduino through SPI.
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The sensor inputs from the handle sensor and the thermocouple
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are fed into the Arduino directly and are used in the control loop.
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That's about it. There is still some uncertainty about some desin points,
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but I am feeling confident that this should, at least roughly, work.
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[1]: {{<relref "2018-06-20-Reverse-Engineer-a-Saike-858D.md">}}
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