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Microlab 300
Service manual
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Vitalab Microlab 300 Service manual

VITAL SCIENTIFIC N.V.
Micro Series
Service Manual – Micro Series V. 1.00
The contents of this manual with all figures, tables and graphics are intellectual property of Vital Scientific. Unauthorised commercial or non-commercial extracting or copying of contents or use of this manual (in total or in parts) are strictly forbidden unless the editor gives prior written permission.
This manual was written and produced with the utmost care. However, errors cannot be fully excluded. Vital Scientific does not take any responsibility and accepts no liability for incidents of any kind that may occur due to errors contained in this manual.
All product names that are mentioned in this manual are registered trademarks. The manual describes the Micro Series analyser system and its software version 1.0 (August 2001).
The Micro Series is conceptualised, manufactured and tested in accordance with the declaration of con­formity. The declaration is supplied with each device in a separate file.
Please call your local distributor if you need advice or have any questions.
Manufacturer: Vital Scientific N.V.
PO box 100
NL 6950 AC Dieren
The Netherlands
Telephone: +31 313 430 500
Telefax: +31 313 427 807
e-mail: info@vital.nl
Internet: www.vital.nl
Article No.: 6002-310-450
This manual was conceptualised, written and layouted by Scriptor, Dokumentations Service GmbH, Bielefeld, Germany for Vital Scientific.
Service Manual – Micro Series V. 1.00
VITAL SCIENTIFIC N.V.
Table of Contents
Table of Contents
VITAL SCIENTIFIC N.V.
Service Manual – Micro Series V. 1.00
TOC - 1
Table of Contents
1. Safety Precautions and Potential Hazards
1.1 General................................................................................................................................ 1 - 2
1.2 Operator Qualifications........................................................................................................ 1 - 2
1.3 Service Technician Qualifications .......................................................................................1 - 2
1.4 Description of Symbols........................................................................................................ 1 - 2
1.5 Electrical .............................................................................................................................. 1 - 3
1.6 Mechanical........................................................................................................................... 1 - 3
1.7 Lamp.................................................................................................................................... 1 - 3
1.8 Chemical.............................................................................................................................. 1 - 3
1.9 Biohazardous Materials .......................................................................................................1 - 4
Samples .............................................................................................................................1 - 4
Waste Solution and Solid Wastes .......................................................................................1 - 4
Biohazardous Parts .............................................................................................................1 - 4
Reagents .............................................................................................................................1 - 4
1.10 Additional precautions .........................................................................................................1 - 5
Flammables ......................................................................................................................... 1 - 5
Accuracy/Precision of Measured Results............................................................................ 1 - 5
Application ........................................................................................................................... 1 - 5
Operation and Maintenance ................................................................................................ 1 - 5
Installation Requirements .................................................................................................... 1 - 6
Instrument Unused for a Long Period of Time ....................................................................1 - 6
2. Introduction
2.1 System Overview................................................................................................................. 2 - 2
2.2 Using the Service Manual.................................................................................................... 2 - 3
2.3 Repair Policy........................................................................................................................ 2 - 4
2.4 Spare Parts.......................................................................................................................... 2 - 4
2.5 Technical Assistance........................................................................................................... 2 - 4
2.6 Service Training................................................................................................................... 2 - 5
2.7 Field Service Information..................................................................................................... 2 - 5
3. Shipping and Unpacking
3.1 General................................................................................................................................ 3 - 2
3.2 Transport .............................................................................................................................3 - 2
3.3 Storage ................................................................................................................................3 - 2
3.4 Unpacking the Instrument.................................................................................................... 3 - 2
3.5 Contents of Package ...........................................................................................................3 - 3
TOC - 2
Service Manual – Micro Series V. 1.00
VITAL SCIENTIFIC N.V.
Table of Contents
4. Installation Procedures
4.1 General................................................................................................................................ 4 - 2
4.2 Technical Data..................................................................................................................... 4 - 2
4.3 Important Notice Concerning Requirements ....................................................................... 4 - 3
4.3.1 Installation procedures ......................................................................................... 4 - 3
4.3.2 Installation ............................................................................................................ 4 - 4
4.3.3 Line voltage.......................................................................................................... 4 - 4
4.3.4 Turning on the instrument .................................................................................... 4 - 5
4.3.5 Password levels ................................................................................................... 4 - 5
4.3.6 Check lamp alignment ......................................................................................... 4 - 6
4.4 Serial interface (if required) ................................................................................................. 4 - 7
4.4.1 Baud rate.............................................................................................................. 4 - 7
4.4.2 Interface cable connections ................................................................................. 4 - 7
4.4.3 Software requirements ......................................................................................... 4 - 8
5. Physical Description of the Instrument
5.1 Overview.............................................................................................................................. 5 - 2
5.2 Mechanical Design .............................................................................................................. 5 - 2
5.3 Schematic Diagram of System ............................................................................................ 5 - 3
5.4 Optical System .................................................................................................................... 5 - 4
5.5 Fluid System........................................................................................................................ 5 - 5
5.6 Description of Function........................................................................................................ 5 - 7
5.6.1 System organisation and data structure............................................................... 5 - 7
5.6.2 Signal processing................................................................................................. 5 - 7
5.6.3 Temperature control............................................................................................. 5 - 9
5.6.4 Testing and diagnostic routines........................................................................... 5 - 9
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Service Manual – Micro Series V. 1.00
TOC - 3
Table of Contents
6. Technical Information
6.1 Overview.............................................................................................................................. 6 - 2
6.2 Instrument Component Groups ........................................................................................... 6 - 2
6.3 Processor Board.................................................................................................................. 6 - 3
6.3.1 Power supplies, detailed specifications ............................................................... 6 - 4
6.3.2 Microcontroller and logic core .............................................................................. 6 - 5
6.3.3 Signal conversion control ..................................................................................... 6 - 5
6.3.4 Light source control .............................................................................................. 6 - 6
6.3.5 Temperature control ............................................................................................. 6 - 6
6.3.6 Pump control ........................................................................................................ 6 - 6
6.3.7 Valve control ........................................................................................................ 6 - 7
6.3.8 Filterwheel control ................................................................................................ 6 - 7
6.3.9 Sipper interface .................................................................................................... 6 - 7
6.3.10 LCD interface .......................................................................................................6 - 7
6.3.11 Matrix keyboard interface..................................................................................... 6 - 7
6.3.12 PS2 keyboard interface........................................................................................ 6 - 8
6.3.13 Epson M-180 internal printer interface ................................................................. 6 - 8
6.3.14 IEEE1284 external printer interface ..................................................................... 6 - 8
6.3.15 RS232 communication interface .......................................................................... 6 - 8
6.3.16 Display.................................................................................................................. 6 - 8
6.4 Integrated Photometer Board ..............................................................................................6 - 9
6.5 Power Supply.....................................................................................................................6 - 11
6.6 Pump Unit.......................................................................................................................... 6 - 11
6.7 Optical Unit ........................................................................................................................ 6 - 12
6.8 Printer ................................................................................................................................6 - 12
TOC - 4
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Service Manual – Micro Series V. 1.00
Table of Contents
7. Maintenance
7.1 Overview.............................................................................................................................. 7 - 2
7.2 Preventative Maintenance................................................................................................... 7 - 2
7.3 Yearly Maintenance............................................................................................................. 7 - 3
7.4 Maintenance Procedures .................................................................................................... 7 - 4
7.4.1 Cleaning the cover ............................................................................................... 7 - 4
7.4.2 Emptying the fluid system .................................................................................... 7 - 4
7.4.3 Removing covers ................................................................................................. 7 - 5
7.4.4 Cleaning the base plate ....................................................................................... 7 - 5
7.4.5 Cleaning the fluid system..................................................................................... 7 - 6
7.4.6 Mounting IFL filters .............................................................................................. 7 - 8
7.4.7 Removing / replacing the flow cell ....................................................................... 7 - 9
7.4.8 Replacing the lamp ............................................................................................ 7 - 11
7.4.9 Adjusting the lamp ............................................................................................. 7 - 11
7.4.10 Replacing a valve............................................................................................... 7 - 12
7.4.11 Replacing the bellows ........................................................................................ 7 - 13
7.4.12 Replacing tubes ................................................................................................. 7 - 14
7.4.13 Replacing fuses ................................................................................................. 7 - 15
7.4.14 Replacing fuse on power supply (mains) ........................................................... 7 - 16
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8. Tests and Diagnostic Procedures
8.1 Overview.............................................................................................................................. 8 - 2
8.2 Power On Check ................................................................................................................. 8 - 2
8.2.1 RAM test .............................................................................................................. 8 - 2
8.2.2 Non-volatile RAM test .......................................................................................... 8 - 2
8.2.3 FLASH MEMORY test ......................................................................................... 8 - 2
8.2.4 Mechanical reset .................................................................................................. 8 - 3
8.2.5 Filterwheel reset................................................................................................... 8 - 3
8.3 Internal Diagnostics ............................................................................................................. 8 - 4
8.4 Service Level Software........................................................................................................ 8 - 4
8.4.1 Adding filter wavelengths ..................................................................................... 8 - 6
8.4.2 Setting the transport volume ................................................................................ 8 - 6
8.4.3 Defining the number of open channels ................................................................ 8 - 6
8.4.4 Changing the service level password .................................................................. 8 - 7
8.5 Service Maintenance ........................................................................................................... 8 - 8
8.5.1 OPTICAL category settings ................................................................................. 8 - 9
8.5.1.1 Checking the filters ............................................................................................8 - 10
8.5.1.2 Check correct functioning of pump .................................................................... 8 - 11
8.5.2 TEMPERATURE category settings ................................................................... 8 - 12
8.5.2.1 Deactivating the temperature controller............................................................. 8 - 12
8.5.2.2 Setting the sensor offset ....................................................................................8 - 13
8.5.3 LIQUID category settings ................................................................................... 8 - 14
Service Manual – Micro Series V. 1.00
TOC - 5
Table of Contents
9. Troubleshooting
9.1 Overview.............................................................................................................................. 9 - 2
9.1.1 Electronic failures .................................................................................................9 - 3
9.1.2 Processor board ................................................................................................... 9 - 3
9.1.3 Mechanical failures .............................................................................................. 9 - 3
9.2 Error Messages ................................................................................................................... 9 - 4
9.3 Warnings............................................................................................................................ 9 - 13
10. Mechanical Drawings
10.1 Spare parts list................................................................................................................... 10 - 2
System overview ...............................................................................................................10 - 3
MODULE 1A Baseplate.....................................................................................................10 - 4
MODULE 1B Baseplate.....................................................................................................10 - 5
MODULE 2 Display / Processor Board .............................................................................10 - 6
MODULE 3A Pump-unit (housing translucent).................................................................. 10 - 7
MODULE 3B Pump-unit ....................................................................................................10 - 8
MODULE 4A Optical unit................................................................................................... 10 - 9
MODULE 4B Optical unit................................................................................................. 10 - 10
MODULE 4C Optical unit.................................................................................................10 - 11
MODULE 5 Printer unit .................................................................................................... 10 - 12
MODULE 6 Service cover ...............................................................................................10 - 13
MODULE 7A Top cover ...................................................................................................10 - 14
MODULE 7B Top cover ...................................................................................................10 - 14
Appendix
A.1 Target Host Communication................................................................................................A - 2
A.1.1 Serial interface design..........................................................................................A - 2
A.1.1.1 Physical layer ...................................................................................................... A - 3
A.1.2 Packet layer .........................................................................................................A - 4
A.1.2.1 Heartbeat mechanism ......................................................................................... A - 6
A.1.3 Message layer ......................................................................................................A - 8
A.1.4 Application layer ...................................................................................................A - 9
A.1.5 Interface description .............................................................................................A - 9
A.1.5.1 Glossary of terms .................................................................................................A - 9
A.1.5.2 Response classification........................................................................................A - 9
A.1.5.3 HOS-Target events ............................................................................................A - 10
A.2 Routines.............................................................................................................................A - 14
A.3 ID PCB...............................................................................................................................A - 16
A.3.1 Photometer board ..............................................................................................A - 16
A.3.2 Processor board .................................................................................................A - 17
A.4 Electrical Drawings ............................................................................................................A - 18
A.4.1 Functional electronics diagram ..........................................................................A - 19
VITAL SCIENTIFIC N.V.
TOC - 6
Service Manual – Micro Series V. 1.00
Mechanical Drawings 10
10. Mechanical Drawings
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Service Manual – Micro Series V. 1.00
10 - 1
10 Mechanical Drawings
10.1 Spare Parts List
These pages offer you an overview of the ordering numbers annotated to the modular groups as they are required for the Micro Series. Dealers should always consult the latest price list for current ordering information.
Part number Page Part number Page Part number Page
1503-008 10 - 10 3070-479 10 - 13 3380-354 10 - 13
1513-001 (36 mm) 10 - 10 3070-480 10 - 14 3390-042 10 - 11
1513-052 (52 mm) 10 - 7 3073-025 10 - 12 3390-131 10 - 6
1513-052 (75 mm) 10 - 7 3073-105 10 - 12 3750-055 10 - 9
1513-052 (68 mm) 10 - 8 3074-100 10 - 12 3820-406 10 - 14
1513-024 10 - 8 3315-276 10 - 5 4100-347 10 - 7
1573-001 10 - 7 3342-855 10 - 14 4100-750 10 - 10
3002-224 10 - 14 3348-175 10 - 5 4100-752 10 - 7
3002-307 10 - 9 3348-123 10 - 4 4104-118 10 - 10
3004-216 10 - 9 3350-156 10 - 9 4509-217 10 - 10
3029-039 10 - 7 3359-041 10 - 4 4800-300 10 - 3
3059-017 10 - 14 3366-922 10 - 7 4801-142 10 - 11
3066-129 10 - 5 3367-054 10 - 11 4802-422 10 - 13
3066-138 10 - 7 3367-055 10 - 6 6002-313 10 - 12
3066-138 10 - 8 3370-526 10 - 5 6002-320 10 - 10
3066-140 10 - 5 3370-761 10 - 5 6002-321 10 - 10
3066-141 10 - 7 3370-762 10 - 5 6002-322 10 - 11
3066-146 10 - 8 3374-101 10 - 4 6002-326 10 - 7
3066-147 10 - 8 3374-102 10 - 4 6002-332 10 - 8
3067-340 10 - 10 3374-103 10 - 8 6002-333 10 - 7
3067-405 10 - 10 3374-104 10 - 11 6002-333 10 - 8
3067-505 10 - 10 3374-105 10 - 3 6002-341 10 - 6
3067-546 10 - 10 3374-108 10 - 4 6002-342 10 - 8
3067-578 10 - 10 3374-112 10 - 8 6002-344 10 - 4
3067-620 10 - 10 3374-112 10 - 11 6002-345 10 - 11
3070-472 10 - 9 3374-112 10 - 12 6002-339 10 - 14
3070-473 10 - 9 3380-018 10 - 9
10 - 2
3070-477 10 - 9 3380-353 10 - 13
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Service Manual – Micro Series V. 1.00
System Overview
Mechanical Drawings 10
Part number Item Amount
A
B
C
D
4800-300 Lamp cover 1
E
F
3374-105 Cable assy 1
G
Printer-assy 1
Pump assy 1
Display 1
Processor board 1
Optical-unit 1
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Service Manual – Micro Series V. 1.00
10 - 3
10 Mechanical Drawings
MODULE 1A Baseplate
Part number Item Amount
3066-140 Socket 1
A
6002-344 Fan unit inc. connector 1
B
3374-102 Mains cable 1
C
3348-123 Fuse, glass 3 A/250 V fast blow 1
D
3359-041 Power supply 1
E
3374-108 Earth cable 1
F
3374-101 Power dc cable 1
G
10 - 4
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Service Manual – Micro Series V. 1.00
MODULE 1B Baseplate
Part number Item Amount
3315-276 Line filter 1
A
3348-175 Fuse, glass 259 V/1.6 A slow blow 2
B
3370-526 Screw locks, female 4-40 unc 4
C
3370-761 Guard, retainer & filter 1
D
3370-762 Filter foam 1
E
3066-129 Nut 1
F
3066-140 Socket 1
G
Mechanical Drawings 10
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Service Manual – Micro Series V. 1.00
10 - 5
10 Mechanical Drawings
MODULE 2 Display / Processor Board
Part number Item Amount
6002-341 Display inc. connectors 1
A
3390-131 Battery 3.6 V 1
B
3367-055 Processor board 1
C
10 - 6
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Service Manual – Micro Series V. 1.00
MODULE 3A Pump-unit (housing translucent)
Mechanical Drawings 10
Part number Item Amount
6002-333 Valve cable assy 2
A
3366-922 Valve 2
B
1513-052 Tube, PVC 1.5 x 3.5 mm clear (5 m) 2 x 75 mm
C
3066-138 Connector. 10-32 UNF 2
D
4100-752 Cover 1
E
3029-039 O-ring 1
F
4100-347 Bellows 1
G
1513-052 Tube, PVC 1.5 x 3.5 mm clear (5 m) 1 x 52 mm
H
3066-141 Connector 1
I
1573-001 Tube, silicone 0.8 x 2.4 mm (1 m) 1 x 30 mm
J
6002-326 Stepper motor 1
K
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Service Manual – Micro Series V. 1.00
10 - 7
10 Mechanical Drawings
MODULE 3B Pump-unit
Part number Item Amount
3066-147 Male luer connector 1
A
1513-024 Tube, PVC 4 x 8 mm (1 m) 1 x 240 mm
B
3374-103 Pump cable 1
C
6002-342 Pump board assy 1
D
6002-332 Opto assembly 1
E
3066-138 Connector 10-32 UNF 2
F
1513-052 Tube, PVC 1.5 x 3.5 mm clear (5 m) 1 x 68 mm
G
6002-333 Valve cable assy 2
H
3066-146 Socket 1
I
3374-112 Earth strap 1
J
10 - 8
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Service Manual – Micro Series V. 1.00
MODULE 4A Optical unit
Mechanical Drawings 10
Part number Item Amount
3750-055 Spring 2
A
3350-156 Lamp socket 1
B
3004-216 Screw M 3 x 20 2
C
3002-307 Screw M 3 x 8 2
D
3380-018 Halogen lamp 12 V/20 W 1
E
3070-477 Top sipper housing 1
F
3070-472 Sipper housing 1
G
3070-473 Lever 1
H
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Service Manual – Micro Series V. 1.00
10 - 9
10 Mechanical Drawings
MODULE 4B Optical unit
Part number Item Amount
4509-217 Disk 1
A
6002-320 Indicator board assy 1
B
4100-750 Prop 6
C
1513-001 Tube, PVC 2 x 4 mm clear (5 m) 1 x 36 mm
D
4104-118 Pipe 1
E
3067-340 Filter IFL 340 nm 1
F
3067-405 Filter IFL 405 nm 1
G
1503-008 Tube, PTFE 0.7 x 1.6 mm (1 m) 1 x 255 mm
H
3067-505 Filter IFL 505 nm 1
I
6002-321 Opto board assy 1
J
3067-546 Filter IFL 546 nm 1
K
3067-578 Filter IFL 578 nm 1
L
3067-620 Filter IFL 620 nm 1
M
10 - 10
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Service Manual – Micro Series V. 1.00
MODULE 4C Optical unit
Mechanical Drawings 10
Part number Item Amount
3374-112 Earth strap 1
A
3390-042 Peltier element 1
B
6002-345 House assy 1
C
6002-322 Motor unit 1
D
4801-142 Cover 1
E
3367-054 Photometer board 1
F
3374-104 Photometer unit cable 1
G
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Service Manual – Micro Series V. 1.00
10 - 11
10 Mechanical Drawings
MODULE 5 Printer unit
Part number Item Amount
6002-313 Printer 1
A
3074-100 Cable assy 1
B
3073-105 Ink ribbon cassette 1
C
3073-025 Paper roll (indicated) 1
D
3374-112 Earth strap 1
E
10 - 12
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Service Manual – Micro Series V. 1.00
MODULE 6 Service cover
Mechanical Drawings 10
Part number Item Amount
3070-479 Service cover 1
A
3380-354 Grommet 1
B
3380-353 Light tube 1
C
4802-422 Cutter 1
D
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Service Manual – Micro Series V. 1.00
10 - 13
10 Mechanical Drawings
MODULE 7A Top cover
MODULE 7B Top cover
Part number Item Amount
3070-480 Top cover 1
A
3059-017 Window 1
B
3820-406 Display sticker (standard version) 1
C
3342-855 Keyboard 1
D
3002-224 Screw 3 x 8 2
E
6002-339 Keyboard interconn. board 1
F
10 - 14
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Service Manual – Micro Series V. 1.00
Appendix
Appendix
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Service Manual – Micro Series V. 1.00
A - 1
Appendix
A.1
A.1.1 Serial interface design
Target Host Communication
The Target-Host communication for the Micro Series is divided into a number of layers. This chapter offers a description of these layers in the model:
− Serial interface design.
− Physical layer includ ing pi n ass ignments etc.
− Packet layer including packet type field definition.
− Heartbeat mechanism including protocol usage.
− Message layer including header definition.
− Application layer including.
Figure 1 offers an overview of the layers in the model.
Host Target
Appli ca tion Layer
Message Layer
Packet Layer
Physical Layer
Figure 1: Communication Layer Model
Appli ca tion Layer
Message Layer
Packet Layer
Physical Layer
A - 2
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Service Manual – Micro Series V. 1.00
A.1.1.1 Physical layer
The physical layer is used to transfer bytes between target and host. This is achieved by means of an RS232 interface. The target is supplied via a 9-pins DB9 male connector. The connections are shown in the following table:
Pin Signal In/Out
1 DCD In 2Rx In 3Tx Out 4DTR Out 5GND ­6DSR In 7RTS Out 8CTS In 9RI In
Appendix
(from point of view of the Target)
Table 1: Pinning of the Host DB9 male connector Only the Rx and Tx signals are used to transfer bytes between target and host. There will be no
hardware handshaking between target and host. The baud rate is
and no parity bit. In order to connect a PC Host to the target, a simple NULL-modem (crossed Rx/Tx signals) ca-
ble is sufficient. The signal levels comply with the RS232 specification. The cable length between Target and
Host is specified as being less then 10 meters.
fixed at 9600 Baud
. Bytes are transferred with 1 start bit, 8 data bits, 1 stop bit
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Service Manual – Micro Series V. 1.00
A - 3
Appendix
A.1.2 Packet layer
The packet layer offers reliable and error-free packet transfer across the connection. It imple­ments error detection and recovery on packet level, so the message layer is assured that pack­ets sent reach the other side without corruption, and also that incoming packets are not cor­rupted.
A packet consists of a number of bytes. Its format is:
Header (1 byte 0xFF)
The Header byte is defined as hexadecimal value 0xFF. The next field consists of a byte indi­cating the number of bytes in this packet This defines the maximum packet size to 257 bytes. The Data field is at most 253 bytes.
The type field indicates the contents of the packet. This is either:
Type bits Description
000 001
010
011
100
101 Reserved. Do not send a packet with this type. Ignore received packets with this
Length (1 byte)
data
packet containing n bytes of message data in the Data field.
ACK
packet, acknowledging a previously received data packet. The Data field is
empty.
NACK
packet, indicating an error in a previously received data packet. The Data
field is empty.
Heartbeat Request
is empty.
Heartbeat Acknowledge
field is empty.
type.
Type (3 bits)
after
packet, used for communication status polling. The Data field
packet, used for communication status polling. The Data
ID (5 bits)
the length field, including the checksum byte.
Data (n bytes)
Checksum (1 byte)
A - 4
110 Reserved. Do not send a packet with this type. Ignore received packets with this
type.
111 Reserved. Do not send a packet with this type. Ignore received packets with this
type.
Table 2: Packet Type field definition The ID is a modulo 32 number identifying a data packet. This is used on the target side to notice
multiple transmissions of the same data packet. In case of ACK or NACK, the ID field is set to 0. If a packet is a data packet, n bytes of data reside in the data field. The number of bytes of the
data field is calculated as: If it’s an ACK or NACK packet, the Data field is empty. Finally, a checksum byte is added. The checksum is a modulo 256 addition of all packet bytes
following the header byte till the checksum byte, subtracted from 256. Therefore, the sum of all bytes following the header including the checksum byte must be zero.
n = Length - 2
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Appendix
The following tables show the usage of the packet protocol under several conditions:
A: The data packet #0 is received correctly at the target, and the ACK is received correctly at
the host.
B: The data packet #1 is corrupted, so a NACK is returned. The host responds with a retry,
which works correctly.
C:
The host sends a data packet #2, but it never reaches the target. After a time-out period, if still no ACK or NACK has been received, the host does a retry.
D: A data packet #4 is received correctly at the target, which responds with an ACK. However,
the ACK doesn't reach the host or becomes corrupted. After a time-out period, the host responds with a retry of data packet #3. The target receives another data packet #3, which is
sent to higher level software because it already received a correct data packet #3.
not
The receiving is acknowledged to the target, though.
When a value 0xFF within a packet is falsely seen as a packet header, the packet Layer will re­cover from this error by means of the packet timeout or a checksum failure: The receiver ex­pects a number of bytes determined by the byte received after the 0xFF. If the receiver expects too many bytes, a packet timeout will occur after the sender has sent the last byte of the packet. If the receiver expects the exact amount or less bytes than the remaining bytes in the current packet, a checksum failure occurs, and the receiver will wait for the next packet header.
A number of parameters must be determined: Packet time-out: This is the maximum time between the first bytes of a packet (0xFF)
and the last byte of a packet. The receiver starts a timer when the header byte is received. The complete package must be received before expiration of the timer. If the timer expires before packet completion, a packet time-out has occurred and another start-of­packet is awaited. (The bytes received so far are ignored.)
The value chosen for the packet time-out is This mechanism will prevent a system lock-up when the serial con-
nection is lost in the middle of a packet transfer. reported to higher software levels.
Ack/Nack time-out: This is the maximum time that is waited for an ACK or NACK packet
after sending a data packet. If after this time no ACK or NACK is received, a retry is performed. The value chosen for the Ack/Nack time-out is
Packet maximum retries: This is the maximum number of consecutive retries for sending
packets. If this number is exceeded, a communication error is reported to the message layer.
2 seconds
.
1 second.
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Service Manual – Micro Series V. 1.00
The maximum number of packet retries is set to 5.
A - 5
Appendix
A.1.2.1 Heartbeat mechanism
The packet layer on the target will implement a mechanism to detect the availability of a logical connection to a packet layer on a host. It will do so by sending ‘heartbeat request’ packages at a certain time interval (Heartbeat Frequency). A packet layer on the host must respond within a certain timeout (Heartbeat Timeout) with a ‘heartbeat acknowledge’ packet. If the host responds in time, the logical connection is available. If no response is received, or not in time, a logical connection is not available.
The Heartbeat Frequency is set to ‘one heartbeat per seconds’. The Heartbeat Timeout is set to 5 seconds.
A host can use the same mechanism to detect the availability of the target. The host is also allowed to send a ‘heartbeat request’ package to the host in order to detect the
presence of the target. The target will respond with a ‘heartbeat acknowledge’ as soon as it re­ceives a request.
A - 6
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Service Manual – Micro Series V. 1.00
Appendix
Host
Ph ysical Layer
A
B
C
Send Packet
Packet Sent
Send Packet
Packet Sent
Send Packet
Packet Sent
Timeout
Retry
Retry
packet(0)
Ack
packet(1)
NAck
packet(1)
Ack
packet(2)
packet(2)
Ack
Figure 2: Packet Protocol usage (1)
Target
Ph ysical Layer
Incorrect Checksum
Nothing received
Packet Received
Packet Received
Packet Received
Host
Physcial Layer
D
Send Packet
Packet Sent
Nothing received
Timeout
Retry
packet(3)
Ack
packet(3)
Ack
Figure 3: Packet Protocol usage (2)
Target
Physical Layer
Only ACK, do not send to message layer
Packet Received
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Appendix
A.1.3 Message layer
The message layer provides a way for the application layer to send and receive messages of random length. The message layer cuts outgoing messages into packets and sends them across the connection by means of the packet layer. The message layer concatenates incoming packets to form a complete message. This is shown in Figure 4.
Header Data Header Data Header Data
Packet Data
Figure 4: Message to multiple pack e t transf ormation The target is capable of receiving a message that consists of 1 packet maximum. This sets the
maximum message size to 252 bytes. This is sufficient for all the application messages used by the target.
Message
A 1 byte header is added to the message data in a packet before it is sent. This header indi­cates if it is the first packet, an intermediate packet or the last packet of the message. While re­ceiving messages, this information is used to detect start and finish of the message.
Header definition:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved Res erved Reserved Res erved Reserved Reserved Last
packet of message
First packet of message
If a message fits into one packet, this will be both the first and last packet of the message. A packet is an intermediate packet when neither of the two bits is set. The reserved bits must be set to 0 when a packet is sent.
If transmission of one of the packets fails (even after retries), the transfer of the message is aborted and an error reported to the application layer. (The message layer does not perform retries, since a retry-mechanism is available on the packet layer.)
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