Hitachi RAS-35FH6 - Interface Circuit Used for the Indoor and Outdoor Microcomputers to Communicate with each Other

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Fig. 3-1 shows the interface circuit used for the indoor and outdoor microcomputers to communicate

with each other.

Fig. 3-1

Control P.W.B.

Main Page

Table of Contents1
Specifications1
Room Air Conditioner1
Technical Information1
Service Manual1
Safety During Repair Work2
Working Standards for Preventing Breakage of Semiconductors3
Grounding of the Working Table4
Grounding a Soldering Iron4
Specifications6
- Safety Precaution7
- Precautions During Installation7
- Precautions During Shifting or Maintenance7
How to Use7
- Name and Function of each Part8
- Indoor Unit8
- Outdoor Unit8
- Indoor Unit Indications8
- Automatic Operation9
- Remote Controller9
- Auto Restart Control9
- Various Functions9
- Heating Operation10
- Dehumidifying Operation10
- Defrosting10
- Dehumidifying Function10
- Cooling Operation11
- Fan Operation11
- Fan Speed (Auto)11
- How to Set the Timer12
- How to Cancel Reservation12
- Time12
- Off-Timer12
- How to Set the Sleep Timer13
- Adjusting the Air Deflectors13
- How to Exchange the Batteries in the Remote Controller13
- Cleaning of Front Panel14
- Maintenance at Beginning of Long off Period14
- Air Filter14
- Maintenance14
- Information15
- Regular Inspection15
- After Sales Service and Warranty15
- Capabilities15
Construction and Dimensional Diagram17
- Construction and Dimensional Diagram18
- Main Electric Components for Outdoor Unit19
- Thermostat19
- Fan Motor19
Main Parts Component19
- Compressor Motor20
- Compressor Motor Specifications20
- Front Side of Outdoor Unit20
Wiring Diagram21
Circuit Diagram22
Block Diagram24
Basic Mode25
- Mode Data File26
- Basic Cooling Operation27
- Thermo Judgment27
- Compressor Speed27
- Cooling Sleep Operation28
- Cooling Defrost28
- Dehumidifying Sleep Operation28
- Basic Heating Operation29
- Setting Defrosting Inhibit Period30
- Heating Sleep Operation30
- Reversing Valve Defrosting30
Refrigerating Cycle Diagram31
Reset Circuit32
Description of Main Circuit Operation32
- Receiver Circuit33
- Buzzer Circuit33
- Buzzer Operation33
- Microcomputer Output Signals34
- Auto Sweep Motor Circuit34
- Auto Sweep Motor Drive Circuit34
- Initial Setting Circuit (IC401)35
- Power Supply35
- Fan Motor Drive Circuit36
- Model RAC-35YH637
- Power Circuit38
- Indoor/Outdoor Interface Circuit40
- Interface Circuit Used for the Indoor and Outdoor Microcomputers to Communicate with each Other41
- Voltages Waveforms of Indoor / Outdoor Microcomputers (Outdoor to Indoor Communications)42
- Voltages Waveforms of Indoor / Outdoor Microcomputers (Indoor to Outdoor Communications)42
- Serial Communications Format During Normal Communications43
- Serial Communications Data44
- IPM (Intelligent Power Module)45
- Intelligent Power Module and Its Peripheral Circuit45
- Switching Order of Power Module46
- Voltage Waveform at each Point46
- Power Module Circuit47
- IPM Drive Circuit48
- Power Circuit for P.W.B.49
- Check Points50
- Microcpomputer's Peripheral Circuits51
- Overload Control Circuit (OVL Control Circuit)51
- Is Ovl52
- ID Ovl52
- Rotation Speed Control52
- Start Current Control53
- Waveform at each Point54
- Temperature Detection Circuit55
- Reversing Valve Control Circuit56
- Electric Expansion Valve Control Circuit57
- Outdoor DC Fan Motor Control Circuit58
- Service Call Questions and Answers60
- Cooling Mode60
- Dehumidifying Mode60
- Heating Mode60
- Infrared Remote Control61
- Auto Operation61
- RAC-35YH6 Precautions for Checking63
Trouble Shooting63
- Discharge, Procedure and Power Shut off Method for Power Circuit64
- Discharge Procedure64
- Structure of an Indoor Unit Electric Parts (RAS-35FH6)65
- Removing Electrical Parts65
- Removing Control P.W.B.65
- Removing the Indicating P.W.B.65
- Other Cautions66
- The Support Function of Failure Diagnosis67
- Troubleshooting When Timer Lamp Blinks68
- Self-Diagnosis Lighting Mode68
- Remove the Compressor Connector70
Outdoor Unit70
- Checking the Indoor/Outdoor Unit Electrical Parts and Refrigerating71
- Checking the Indoor Unit Electrical Parts72
- Checking the Remote Controller75
- Removing the P.w.b.s76
- Checking the Outdoor Unit Electrical Parts78
- How to Change the Shift Value for Setting Temperature85
- Procedure85
- Checking the Refrigerating Cycle86
- How to Operate Using the Service Switch the Outdoor Unit87
- How to Operate the Outdoor Unit Independently87
- IPM (Intelligent Power Module) Diagnosis88
- Control P.W.B. and Indicating P.W.B.90
- Front Panel90
- Front Cover90
Procedure for Disassembly and Reassembly90
- Outdoor Unit RAC-35YH691
- Tangential Air Flow Fan and Fan Motor91
- Electrical Parts91
- Indoor Unit Exploded View92
Parts List and Diagram92
Outdoor Unit Exploded View94

Hitachi RAS-35FH6 - Interface Circuit Used for the Indoor and Outdoor Microcomputers to Communicate with each Other

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