Sherwood Scientific 860 User manual

860 89 001 Issue 1 22nd September 2008 ECN 536
G:\DOCUMENT CONTROL\Manuals\Autosampler\860\86089001 M860 Service Manual Issue 1.doc
Model 860
AUTOSAMPLER
Service Manual
Sherwood Scientific Ltd
1 The Paddocks
Cherry Hinton Road
Cambridge
CB1 8DH
Tel. [phone]
Fax. + 44 (0)1223 243300
Email: [e-mail]
www.sherwood-scientific.com
Copyright©September 2008

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860 89 001 Issue 1 22nd September 2008 ECN 536 2
Contents
1 General
1.1 Introduction ……………………………………………………. 3
Principles of Operation …………………………………………... 3
Use with a Diluter …………………………………………… 3
Use without a Diluter ………………………………………….. 3
Use with M410 and BlueNotes Software …………….. 3
2 Instrument Description
2.1 General Description …………………………………………… 4
2.2 Connecting the Power Supply …………………………………. 7
2.3 Fitting the SafetyCover …………………………………………… 7
2.4 Setting the Sampling Method ………………………………….. 8
3 Technical Details
3.1 Technical Specification ……………………………………………. 9
3.2 Operating Sequences ……………………………………………. 10
At Power On ……………………………………………………… 10
After Pressing Run ……………………………………………. 10
After Pressing Stop ……………………………………………. 10
3.3 Circuit Description ……………………………………………. 11
Switch PCB ……………………………………………………… 11
Carriage PCB ……………………………………………………… 11
Main PCB ……………………………………………………… 11
3.4 Programming the Microprocessor ………………………… 11
3.5 Fault Conditions ……………………………………………. 12
Initialisation Error ……………………………………………. 12
Movement Error ……………………………………………. 12
Missing Vial ……………………………………………………… 12
Safety Cover ……………………………………………………… 12
Sample Probe Not Central in Vial ………………………… 12
4 Maintenance
4.1 Installing the Sample Probe ………………………………… 13
4.2 Carousel Alignment ………………………………………….. 14
4.3 Setting the Correct Position of the Probe Carrier Assembly ... 15
4.4 Setting the Bottle Sensor Shaft Position ……………………….. 16
4.5 Adjusting the Safety Cover Sensor ……………………….. 17
4.6 Adjusting the Carriage Sensor …………………………………. 20
4.7 Replacing the Main PCB …………………………………. 24
4.8 Replacing the Carriage PCB …………………………………. 27
4.9 Replacing the Switch PCB …………………………………. 36
5 Spares
5.1 Ordering Information ………………………………………….. 42
5.2 Spare Parts ……………………………………………………. 42

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1 GENERAL
1.1 Introduction
Principles of Operation
The Model 860 Autosampler has been designed to work primarily with the Sherwood
Scientific Model 420 and Model 425 Flame Photometers, but can also be used with the
Model 410 Flame Photometer when using the BlueNotes for 410 Software. It can also
be used in conjunction with the Model 805 Continuous Flow Diluter.
For the ‘Blank’ and ‘Calibration’ sequences, the Model 860 responds to signals from the
M420/M425 Flame Photometer and moves automatically to the appropriate vial. Once the
Measure button has been pressed, the Model 860 automatically moves from sample to
sample sending a signal to the Flame Photometer as indicated below.
Use with a Diluter (normally used for clinical samples)
The M860 remembers the position of each Blank, Calibration and Measurement sample
and sends a signal to the M420/M425 Flame Photometer as that sample enters the
Diluter.
The Diluter, via the sampling tubing draws the sample through the Autosampler Probe,
mixes the sample with the diluent and fills the Weir Cup on the Flame Photometer from
which the Flame Photometer aspirates the sample and then measures and displays the
result.
Use without a Diluter
When used without a Diluter, the M860 positions the Autosampler Probe into each Blank,
Calibration and Measurement Sample and the M420/M425 Flame Photometer itself
draws the liquid into the Nebuliser for aspiration into the flame. The M860 sends a signal
to the Flame Photometer immediately the Autosampler Probe descends into the sample
to initiate the measurement.
Use with M410 and BlueNotes
BlueNotesBlueNotes
BlueNotes for 410 Software
Refer to the operator manual of the BlueNotes for M410 for details of connection, set-up
and use with an M410 Flame Photometer.

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2 INSTRUMENT DESCRIPTION
2.1 General Description
Familiarisaton
Fig. 1 - Rear View of Connectors and Dip Switches
Fig. 2 - Top View: Run / Stop Keys
Not
Used
Power
socket
Power
On/Off
switch
Not
Used
I/O for
Model
420/425
Method
DIP
switches
Run Method Key
Stop Method
Clear Fault Key

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Fig. 3 - Status LED’s
Fig. 4 - Autosampler Probe and Safety Cover
Indicates Fault
when flashing
Indic
ates
Ready
or waiting for
Flame
Photometer
when flashing
Indicates
Sampling
Auto sampler
Probe
Plastic Safety
Cover

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The main components of the Model 860 system are shown in the diagram below. The
positions of the Diluter and adapter Plate, which is necessary if the Diluter is to be used,
are also shown.
Fig. 5 - Layout of Autosampler System
(Diluter)
(Adapter
Plate)
Locating
Lug
Auto sampler
Base
Sample
Carousel
Safety cover
Auto sampler
Probe
Auto
sampler
Tower

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2.2 Connecting the Power Supply
Please ensure that you have the Autosampler connected correctly onto the Model
420/425 before connecting it to the power supply.
The electrical connection to the external power supply is made at rear of the instrument,
see Figure 1.
The universal external power supply will operate from an input supply in the range 90V to
240V a.c., 50Hz or 60Hz. Please ensure that the mains supply you are using is suitable.
The mains power cable (not supplied), constructed to British Standard 1363, should be
connected to the IEC socket on the External Power Supply.
A good ground (earth) connection is essential for satisfactory operation of the power
supply and the safety of the user. The mains plug must only be inserted into a socket
outlet provided with an earth contact. This protective action must not be negated by the
use of an extension cable without a protective conductor.
WARNING: Any interruption of the protective conductor inside or outside
the power supply is likely to make the unit dangerous.
2.3 Fitting the Safety Cover
Align the slot in the front of the Safety Cover over the Autosampler Probe and at the
same time locate the Metal Pin on the right hand bottom end of the Safety Cover into the
slot in the front of the instrument housing. Push the top of the Safety Cover onto the
rounded top cover. This is a snug push fit.
Note: The right hand top edge should be flush with the housing to ensure that the
magnetic sensor functions correctly.

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2.4 Setting the Sampling Method
The sampling method is determined by the Model 420/425, the M860 takes signals in
sequence during the Blanking and Calibration phase of the M420/M425 start-up.
Once the M420/M425 is in the Run mode, the Model 860 controls the sequence by a time
delay. The Basic time delay is 30 seconds; this delay can be modified by the setting of
the row of eight DIP switches located at the rear of the unit, (see Figure 1). The DIP
switches are read by the software immediately before each sample. However, it is
recommended that they are set-up before the unit is powered on and not changed in
between samples. Set them up as follows:
Method Parameter
DIP S/W No.
Description
Initial Position:
-
Sampling Delay Time = 30
seconds
All Switches OFF
All Switches in Upper p
osition
1,2,3
For each switch in the ON
(lower) position: - add a 2
second time increment.
4,5,6
For each switch in the ON
(lower) position: - subtract a 2
second time increment.
7
Switch to ON (lower) position
for use without a Diluter.
Auto
-
run
8
Automatically run each sample.
i.e. do not wait for READY
signal.
(Note: except first sample).
Include a 10 second delay
between samples.

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3 TECHNICAL DETAILS
3.1 Technical Specification
Sampling Tray
The Autosampler carousel will handle 40 samples plus a Blank and Calibration Standard
vial.
Vial Volumes
Sample Vials: 2ml
Blank and Standard Vial: 14ml
Sample Volumes
Without Diluter Minimum 1.5ml
With Diluter Minimum 200µl
Sampling Speed
30 seconds per sample ±6 seconds in 2 second steps.
(set via the DIP switches: see Figure 1)
Power Requirements
External power supply
Mains: 90V ±10%, 50/60Hz to 230V ±10%, 50/60Hz.
Output: 32V, 1.56A, 50W.
Size (with Diluter)
Height 380mm
(535mm mounted on Diluter)
Width 235mm
Depth 210mm
Weight
Net weight 4.40 Kg
Packed weight 6.8 Kg
Packed Dimensions 530mm x 360mm x 320mm

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3.2 Operating Sequences
At Power On
When the instrument is first switched on it will perform a self test. The first check is for the
presence of the Safety Cover. A Hall sensor mounted on the Switch PCB inside the top of
the Tower checks for the magnetic field from the magnet in the top right-hand edge of the
Safety Cover. If the magnet cannot be detected the instrument will not progress any
further and an error is indicated by a flashing ‘Status’ LED. To adjust the sensor, follow
the instructions in Section 4.5.
The next check is for the correct starting position of the Carriage. The Carriage will make
small movements up and down aligning the Hall sensor mounted on the back of the
Carriage PCB with the magnet mounted at the top of the Motor Plate. If the magnet
cannot be detected an error is indicated by the ‘Sampling’ LED illuminating. To adjust the
sensor, follow the instructions in Section 4.6.
Assuming the Carousel is near its correct position, it will make small side to side
movements. Unless it is grossly out of position in which case it will motor round to the
start position. The Hall sensor mounted on the Tower Base is looking for the magnetic
field from the magnet on the underside of the Carousel. If the magnet cannot be detected
then an error is indicated by the ‘Ready’ LED illuminating and the ‘Status’ LED flashing.
Should the gap in the Carousel not be central about the Sample Probe, adjust the Sensor
position as described in Section 4.2.
Finally the motor will run to pull the Probe Carrier in towards the body of the instrument,
its start position.
The ‘Ready’ LED will illuminate to indicate a successful initialisation.
After pressing Run
The Carriage will make small up and down movements followed by the Probe Carrier
being pulled inwards, then the Carousel will move side to side.
Once a measurement is initiated the Carriage moves down and the Bottle Sense Shaft is
displaced, moving its magnet away from the Hall Sensor. If this does not happen an error
is indicated by the ‘Sampling’ LED illuminating. For details on adjusting the height of the
Bottle Sense Shaft refer to Section 4.4.
After each measurement when the Carriage lifts the Sample Probe out of a vial, the
instrument checks for the Hall sensor to be triggered by the magnet at the top of the
movement to ensure the Probe and Bottle Sensor are clear of the vials before allowing
the Carousel to rotate.
After pressing Stop
The Carriage will move up to clear the sample vials, the Carousel will rotate to the start
position and the Probe Carrier will be pulled in.

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3.3 Circuit Description
Switch PCB
This contains the two control switches and the Hall sensor for the Safety Cover. It
connects to the Main PCB via a ribbon cable.
Carriage PCB
This contains the three LED’s, the Hall sensor for the Bottle Sensor and connections for
the Probe Carrier motor and position resolver. It connects to the Main PCB via a ribbon
cable.
Main PCB
This contains connections to all the motors, the Switch PCB and the Carriage PCB. Plus
the control DIP switches and the input/output connectors.
Control of the instrument is via a firmware programme from the microprocessor. The
firmware can be updated via the RS232 socket.
3.4 Updating the Firmware
The microprocessor fitted to the M860 has a feature which allows the firmware to be
updated via the RS232 communications port, eliminating the need to remove the
microprocessor.
It requires that the Atmel Flip Utility be downloaded from the Atmel website to your
pc/laptop. www.atmel.com/dyn/products/tools_cad.asp?tool_id=2767 or search for Atmel
Flip. This is a free download.
Download Atmel Flip 2.4.6 or later and start the application.
Connect the M860 to the RS232 port of your computer using the Null Modem Cable
(00109003) supplied with the M860. Move the two DIP switches located at the bottom
right-hand side on the front of the M860 to the down position and switch on the
instrument.
On the Flip utility select the device type AT89C51ED2.
DEVICE> SELECT.
Set the communications to RS232.
SETTINGS> COMMUNICATIONS.
Load the new firmware obtained from your Sherwood distributor.
FILE> LOAD HEX FILE.
When the update is completed, switch off the M860 and return the two DIP switches to
the original up position.

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3.5 Fault Conditions
If an instrument fault occurs or the safety cover is removed during operation, all
movements will stop immediately and the ‘READY’, ‘STATUS’ and ‘SAMPLING’ LED’s
will illuminate according to the fault condition as follows:-
If an error occurs then either, press the ‘STOP/CLEAR’ key on the top of the instrument
which will attempt a re-initialization, or switch the instrument off and correct the cause of
the error before switching back on again.
Initialisation Error
This may be due to the Carriage Assembly vertical movement, see Section 4.6 or the
Probe Carrier horizontal position, Section 4.3.
Movement Error
This can be either vertical or horizontal. Check the Carriage Sensor, Section 4.6 for
vertical movement errors and Section 4.3 for horizontal movement errors of the Probe
Carrier.
Missing Vial
If all the vials are present and correctly seated, first check that the foot of the Vial Sensor
is not twisted out of position and is at the correct height. See Section 4.4.
If the error persists, check the alignment of the Carousel. After initialization the cut-out in
the Carousel should be central about the Sample Probe. Refer to Section 4.2.
Safety Cover
If the Safety Cover is correctly and firmly in place, check that the magnet is present. This
is a small disc in the top right-hand edge of the Safety Cover. If it is present then the
sensor inside the towermay require adjustment. See Section 4.5.
Sample Probe Not Central in the Vial
Adjust the Carousel position sensor to re-align the probe as described in Section 4.2.
READY SAMPLING STATUS
Initialization Error ON OFF Flashing
Movement Error OFF ON
Missing Blank or
Standard Vial OFF OFF Flashing
Safety cover off, OFF OFF Flashing
System error ON ON
Front DIP Switches
Down ON ON ON

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4 MAINTENANCE
4.1 Installing the Sample Probe
1: Switch off the mains power and disconnect the instrument from the Power Supply
Unit.
2: Remove the Safety Cover.
3: Unscrew the M3 x 3mm Socket Screw in the front of the Probe Carrier Assembly,
as shown in Fig. 6.
4: Remove the Probe and install the new one into the Probe Carrier Assembly.
5: Replace the M3 x 3mm Socket Screw and position the bottom of the Probe level
with the top of the Vial Sensor foot, then tighten the screw.
NOTE: Do Not over tighten.
6: Replace the Safety Cover on the front of the Tower Cover.
Fig. 6

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4.2 Carousel Alignment
1: Switch off the mains power and disconnect the instrument from the Power Supply
Unit.
2: Carefully lift the Carousel up over the Tower.
3: Adjust the position of the Carousel Sensor by loosening the two screws shown in
Fig. 7. Then move the Sensor in the direction required to adjust the Carousel
position on start-up.
The Sensor is moved backwards to adjust the Carousel Anticlockwise and forwards to
adjust the Carousel Clockwise.
NOTE: It may be necessary to adjust the Sensor a few times to achieve the correct
position.
5: Replace the Carousel and re-connect the power. Switch on the instrument and
observe the Carousel position. Adjust the Sensor again if necessary to align the
Carousel centrally.
Fig. 7

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4.3 Setting the Correct Position of the Probe Carrier Assembly
1: Lower the Carousel Assembly down over the Tower and locate it over the Drive
Base with the Teeth engaging in the Toothed Belt.
Note: It does not matter which position the Carousel is in.
2: Remove the Safety Cover.
3: Remove the two Guide Pins from the Carriage Body, as shown in Fig. 8.
4: Push down the right-hand Dip Switch on the front of the Main PCB; this is
accessed through the front of the Base Cover on the bottom right-hand side.
5: Replace the Safety Cover, and then turn the Power on.
6: Remove the Safety Cover and install the Probe Carrier Assembly onto the 7 Start
Screw to within 0.5mm from the face of Carriage Body, as shown in Fig. 8.
7: Replace the two Guide Pins so that they are flush with the end of the 7 Start
Screw, as shown in Fig. 8.
8: Replace the Safety Cover and move the right-hand Dip Switch on front of the
Main PCB to the up position.
9: Turn the Power off, then turn the Power back on, and then turn the Power off
again.
10: Push down the right-hand Dip Switch on the front of the Main PCB.
11: Turn the Power on.
12: Adjust the position of the Probe Carrier Assembly using the buttons on the top of
the instrument. Holding down whichever button to obtain the 0.5mm gap from the
face of the Carriage Body.
13: Move the right-hand Dip Switch on the front of the Main PCB back to the up
position.
The set up is now complete.
Fig. 8

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4.4 Setting the Bottle Sensor Shaft Position
1: Disconnect the M860 from the mains supply.
2: Remove the Safety Cover.
3: Remove the Plastic Cover from the Carriage Body, Note: This is only attached
using double sided tape, see Fig. 9.
4: The Bottle Sense Shaft and Sensor Block will now be exposed. Check the correct
distance of 43mm from the bottom of the Carriage Body to the bottom of Bottle
Sensor Block, as shown below. If this is incorrect, release the grub screw in the
Sensor Block and adjust the height. Remember to keep the Sensor Block and the
Bottle Block square to each other.
5: Check for free movement of the Shaft by pushing the Shaft up into the Carriage
Body.
6: Refit the Plastic Cover to the Carriage Body, and then re-attach the Safety
Cover.
7: The M860 is now ready for use.
Fig. 9

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4.5 Adjusting the Safety Cover Sensor
1:Disconnect the mains supply from the Autosampler and remove the Safety
Cover.
2: Using a sharp tool, remove the Switch Label as shown in Fig. 10.
Fig. 10
3: Remove the Screw in the top of the Tower Cover as shown in Fig. 11.
Fig. 11

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4: Lift the Cover off of the Tower as shown below in Fig. 12.
Fig. 12
5: Slide the Tower Wrapper upwards to remove it from the Frame Assembly, see
Fig. 13.
Fig. 13

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6: Gently push the Sensor outwards about 2mm as shown in Fig. 14. This will
enable the Sensor to register the magnet in the Safety Cover more positively.
7: To re-assemble the Autosampler follow steps 1 to 5 in reverse.
Fig. 14

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4.6 Adjusting the Carriage Sensor
1: Disconnect the mains supply from the Autosampler and remove the Safety
Cover.
2: Using a sharp tool, remove the Switch label as shown in Fig. 10.
Fig. 10
3: Remove the Screw in the top of the Tower Cover as shown in Fig. 11.
Fig. 11