McPHERSON'S 789A-4 User manual

Model 789A-4
Scan Controller
INSTRUCTION MANUAL
Serial Number: ___________________
7A Stuart Road Chelmsford, Massachusetts 01824
PHONE: [phone]
FAX: [phone]
EMAIL: [e-mail]
WWW: http://www.mcphersoninc.com

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WARNING FOR FIELD RETROFITS
ALWAYS CHECK THE MOTOR’S
DEFAULT DIRECTION BEFORE USE.
Older instruments do not have the “Auto Reverse” feature. Please review
Motor Direction section of this manual for options.
If your 789A-4 Controller is replacing Models 788 to 789A-3
Controllers, or is controlling a non-McPherson instrument, consult
the Motor Direction section located in the 789A-4 Instruction
Manual for motor reversal.
If your system has a single 789A-4 Controller matched to an
instrument, it should be factory configured for correct operation.
If your system has multiple 789A-4 Controllers they will be
labeled for their assigned instruments. Verify each 789A-4
Controller is connected to its assigned monochromator or device.
While there is virtually no chance of damage, connecting the
communication cable(s) to the wrong controller(s) will affect your
data.
Configuration Factory Checked
Signed

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CONTENTS
NOTICE .......................................................................................................................................................................4
IMPORTANT NOTICE..............................................................................................................................................5
1.1 FEATURES............................................................................................................................................................6
1.2 SOFTWARE...........................................................................................................................................................6
INSTALLATION.........................................................................................................................................................7
2.1 FUSE REPLACEMENT............................................................................................................................................7
2.2 CONNECTIONS......................................................................................................................................................7
EXPLANATION OF FRONT PANEL......................................................................................................................9
3.1 FRONT PANEL.......................................................................................................................................................9
SETUP........................................................................................................................................................................10
4.1 COM PORT SET-UP............................................................................................................................................10
4.2 MOTOR DIRECTION.............................................................................................................................................10
4.3 789A-4 GRATING SELECTION .............................................................................................................................11
OPERATION.............................................................................................................................................................13
5.1 POWER UP...........................................................................................................................................................13
5.2 HOMING..............................................................................................................................................................13
5.2A HOMING PROCEDURE ......................................................................................................................................14
5.3 789A-4 COMMAND SUMMARY ..........................................................................................................................15
5.3 789A-4 COMMAND SUMMARY (CONTINUED).....................................................................................................16
5.3 789A-4 COMMAND SUMMARY (CONTINUED).....................................................................................................17
5.4 CALCULATING VELOCITY PARAMETER ..............................................................................................................17
5.5 SAMPLE PROGRAM.............................................................................................................................................18
APPENDIX.................................................................................................................................................................19
WARRANTY AND ASSISTANCE..................................................................................................................................19
WARRANTY EXCEPTIONS .........................................................................................................................................20
RETURNING GOODS..................................................................................................................................................21

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NOTICE
THIS EQUIPMENT HAS BEEN CAREFULLY PACKAGED FOR SHIPMENT, AND THE
TRANSPORTATION CARRIER IS RESPONSIBLE FOR DELIVERY TO YOU IN GOOD
CONDITION.
If the shipment is NOT delivered in good condition and in accordance with quantity shown on the Bill of
Lading or Packing Slip, note the shortage or damage on both the delivery receipt and freight bill, or use
the special form provided by United Parcel Service or the Post Office.
EFFECTIVE JULY 1, 1972 the Interstate Commerce Commission has ruled that Transportation
Companies will not honor any losses or damage claims unless exceptions are noted on the freight bill at
the time of delivery. IT IS THE BUYER’S RESPONSIBILITY TO MAKE A COMPLETE
INSPECTION IMMEDIATELY UPON RECEIPT OF PURCHASED GOODS.
If you accept shipment from the transportation carrier short of what is listed on the Bill of Lading - or in
damaged condition - without having proper notation made by the Carrier, you do so at your own risk.
If bundles or crates are in apparent good order but contents are found to be damaged, call Carrier for
adjuster to view same and have the Transportation Carrier/United Parcel/Post Office mark the freight bill
or packing slip relative to such concealed damage.
MAKE YOUR CLAIM AT ONCE, FOR THE TRANSPORTATION COMPANY/UNITED
PARCEL/POST OFFICE HAVE A LIMITED TIME FOR PRESENTATION OF CLAIMS.
We are willing to assist you in every possible manner in collecting claims for loss or damage on this
shipment, but cannot be responsible for filing or collecting claims or replacing materials. Claims for Loss
or Damage on shipment may not be deducted from our invoice, nor payment of the invoice be withheld
awaiting adjustment of such claims, as WE CANNOT GUARANTEE SAFE DELIVERY.

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IMPORTANT NOTICE
ELECTRICAL EQUIPMENT MAY BE DANGEROUS IF NOT HANDLED WITH CAUTION.
ALL INSTRUMENTS SHOULD BE OPERATED WITH PROPER GROUNDS ON POWER
LINES. ELECTRICAL OR ELECTRICALLY OPERATED COMPONENTS SHOULD NOT BE
EXPOSED OR HANDLED WITHOUT BEING SWITCHED OFF AND DISCONNECTED
FROM THE POWER LINE.
McPHERSON WILL NOT BE RESPONSIBLE FOR ANY DAMAGE CAUSED BY SUCH UNITS
IF INSTRUCTIONS HEREIN ARE NOT FOLLOWED, AND REPAIRS ARE NOT
PERFORMED BY COMPANY-TRAINED OR COMPANY-LICENSED PERSONNEL.

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SECTION 1
INTRODUCTION
The Model 789A-4 scan controller is a high resolution stepper system designed to control and drive
McPherson Spectrometers and a variety of other motor driven devices
Easy to program and operate, this scanning system precisely positions gratings or other devices requiring
accurate control.
1.1 Features
Features include:
No confusing switches or controls.
Limit Switch, Homing & Motor Interlock Systems.
LED’s provide “at a glance” system information.
RS232 communication with USB adapter included.
Standard 36000 Steps/Motor Revolution. Up to 50000 Steps/Motor Revolution available; consult factory.
Universal power input (100 to 240 VAC Operation).
1.2 Software
McPherson Spectrometer Control Software is available at an additional cost.

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SECTION 2
INSTALLATION
2.1 Fuse Replacement
To replace the fuse:
1. Locate and remove the fuse slot cover (see Rear Panel diagram below
2. Replace with the following fuse: 2A/250V, SLO-BLO, 5 x 20mm. This fuse is used throughout the
100 to 240 VAC range.
2.2 Connections
Make all connections as shown in the diagram below.
WARNING!
NEVER ATTEMPT TO DISCONNECT OR RECONNECT ANY
CABLING WHILE POWER IS APPLIED.
FAILURE TO OBSERVE THIS PRECAUTION WILL DAMAGE
THE DRIVER CIRCUITRY AND VOID YOUR WARRANTY!
WARNING
Never attempt to disconnect or re-con-nect
the Stepper motor while the “MOTOR”
switch is in the “ENABLE” mode. Failure to
observe this precaution will damage the
driver circuitry and void your warranty!
Power
Input
RS 232
Port
Limit
Switches
Stepping
Motor
Fuse
Slot
connect

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Refer to the diagram below for correct connections between the 789A-4 and the computer’s
COM Port.
Important!
One USB to RS232 Converter is included with the 789A-4 for newer computers without RS232
COM Ports. Please take the time to read the accompanying literature. Use the supplied CD to
install the converter’s drivers. Your computer’s Device Manager is used to configure the port
settings created by the converter. Further information on using Device Manager can be found in
the computer operating system’s Help files.
789A-4 RS232
Computer COM Port

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SECTION 3
EXPLANATION OF FEATURES
3.1 Front Panel
1
Power Switch
Connects/Disconnects Power to the 789A-4 Controller.
2
Limit Switch
Status
Dual colored LED's for high and low limits. LED will show green if
limit switches are operating normally. LED will show red if limit is
engaged or not connected properly. If both LED’s show red, check the
Limit Cable connections.
3
Home Status
LED
Lights when the “Home” switch is blocked during homing function.
This LED is disabled during normal operation.
4
Scan Status
Lights when motor is in motion.
5
Fault LED
Lights when motor is disconnected or driver circuit failure
2
3
4
5
1

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SECTION 4
Setup
4.1 COM Port Set-Up
Apply power to your computer and select a communication program such as “Hyper-Terminal”.
Set RS232 parameters as follows:
Press the spacebar once. If communications have been established, the 789A-4’s serial interface will send
a “sign on” message (for example: “V2.55”) in response to the spacebar. The message will be a firmware
Rev. number. The 789A-4 Controller is now in “Command Mode” and ready to accept more instructions.
NOTE:
If the sign on message does not appear, check the following:
a) Is the 789A-4 powered?
b) Is the RS232 cable connected to the correct COM Port?
c) Are the RS232 Parameters listed earlier set properly?
d) The most frequent problem is the orientation of the receive (RD) and the transmit (TD) lines
of the RS232 connector. For example, the 789A-4 uses a 25 pin “D-Sub” connector. The
illustration in Section 2 shows the typical connection between the 789A-4 and the computer’s
COM Port.
4.2 Motor Direction
If your 789A-4 was purchased with an instrument or device, the default direction has been factory set.
Important!
If the 789A-4 is part of a retrofit kit, the default direction should always be verified before performing
any scans.
1) If possible, manually rotate the motor at least 3 turns toward the center of the leadscrew’s travel.
Note the wavelength counter reading.
2) Apply power to the 789A-4.
3) Enable communication by sending an ASCII space.
4) Send “+36000” with an ASCII [ENTER]. The wavelength counter should have incremented.
5) If the motor rotated in the wrong direction, change the S1 switch to “CW”.
Baud Rate = 9600
Parity = None
Data Bits = 8
Stop Bits = 1
Flow Control = X ON / X OFF

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4.3 789A-4 Grating Selection
Select the instrument(device) from the table below.
789A-4 Grating Selection Table
Monochromator model
Grating,
g/mm
nm/Motor
Rev.
205, 207, 209, 216.5,218,
219, 213, 235, 2051,
2061, 2062, 2062M3
(S/N 100 & above)
150
32
300
16
600
8
1200
4
1800
2.66
2400
2
3600
1.33
205, 207, 209, 216.5,218,
219, 213, 235, 2051,
2061, 2062, 2062M3
(S/N below 100)
150
40
300
20
600
10
1200
5
1800
3.33
2400
2.5
3600
1.66
2035
(S/N 310 & above)
30
500
75
200
150
100
300
50
600
25
1200
12.5
1800
8.33
2400
6.25
3600
4.16
2035 (Up to S/N 309)
275D, 275
100
120
150
80
300
40
600
20
1200
10
1800
6.66
2400
5
3600
3.33

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Monochromator model
Grating,
g/mm
nm/Motor Rev.
272
570
12.5
1140
25
1710
37.5
2280
50
225, 241 2253M5
150
20
300
10
600
5
1200
2.5
1800
1.66
2400
1.25
3600
0.83
X-RAY CZERNEY-
TURNER
(XCT)
100
12
150
8
300
4
600
2
1200
1
1800
0.66
2400
0.5
3600
0.33
302(1), 270(2)
150
16
300
8
600
4
1200
2
1800
01.33
2400
1
3600
0.66
608 Pre-Disperser
N/A
10
248/310G(3)
ALL
0.1 inch
247
ALL
0.025 inch
Motorized slit
N/A
250 µm Typ.
(Check Factory)
1) 5:1 Gear ratio between motor and lead screw.
2) 3:1 Gear ratio between motor and lead screw.
3) Motor set to 18000 steps/motor revolution.

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SECTION 5
OPERATION
5.1 Power up
Once all connections have been made, place the POWER switch to the “ON” position. The LIMIT
STATUS LED’s will light along with the motor “FAULT” LED. After a few seconds, the “FAULT”
LED should turn off. If the “FAULT” LED stays on, check the motor cable connections. If the motor
connections appear good, contact the factory as soon as possible.
For best results:
1) Follow the setup procedures when operating for the first time.
2) Always perform the Homing Procedure anytime power is disconnected from the 789A-4.
3) Consult the McPherson Spectrometer Software manual.
4) If you are not using the McPherson software, follow the Command Summary starting on the
next page.
(a) After power-up, always send an ASCII [SPACE] before any other command is sent.
(b) Start with simple moves until you are comfortable with the controller.
For advanced users, a supplement is included with this manual. This supplement goes into greater detail about
the communications board. Please keep in mind McPherson does not use every command available. Any
commands used that are not listed in this manual run the risk of unstable operation.
5.2 Homing
Homing should always be done prior to scanning after power up.
Your new monochromator is most likely equipped with a “HOME” position switch. Consult the
instrument’s manual for the home wavelength. Do not attempt to home your instrument if there is no
home switch installed.
The “Home Switch” is disabled for routine scanning due to the LED portion emitting IR light, possibly
causing issues in systems working in the IR. The “Home” switch is enabled by sending the ASCII
command “A8” via the RS232 port to the 789A-4 Controller.
Sending the ASCII command “A24” prepares the controller for the final sequence of the homing
procedure.
The homing procedure consists of several steps:
1) Determining if the current wavelength is above or below the “Home” wavelength.
2) Setting the wavelength to the correct starting position
(approximately 1 to 2 motor revolution below Home).
3) Initiating the final homing sequence.
After the homing procedure has completed, sending the command “A0” disables the “Home” switch.

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5.2a Homing Procedure
1) Apply power to 789A-4 Controller and send ASCII[Spacebar] to initialize the 789A-4 COM port.
2) See the Homing Table below.
Finding Home Position with Home Switch Blocked
Line
Command
Explanation
Notes
1
A8
Enable Home Circuit
2
]
Check Limit Status
If Home Switch is blocked, bit 5 is active- response
= 32 “Home” LED is lit.
3
M+23000
Move at constant
velocity (23 KHz)
For a faster move, enter +3000000.
4
]
Check Limit Status
Send every 0.8 seconds until bit 5 clears.
5
@
Soft Stop
Stop when Homing flag is located.
6
-108000
Back into Home Switch
3 motor revolutions
7
+72000
Go 2 motor revolutions
up
Removes backlash
8
A24
Enable “High
Accuracy” Circuit
8
F1000,0
Find edge of Home Flag
at 1000 steps/sec
Scan will stop when edge is found
9
A0
Disable Home Circuit
Necessary on monochromators with Home Switch
inside optic chamber. Switch uses IR LED.
Finding Home Position with Home Switch Clear
Line
Command
Explanation
Notes
1
A8
Enable Home Circuit
2
]
Check Limit Status
If Home Switch is clear, bit 5 is active- response = 0
“Home” LED is not lit.
3
M-23000
Move at constant
velocity (23 KHz)
For a faster result, enter -3000000.
4
]
Check Limit Status
Send every 0.8 seconds until bit 5 is active
5
@
Soft Stop
Stop when Homing flag is located.
6
-108000
Back further into Home
Switch 3 motor
revolutions
7
+72000
Go 2 motor revolutions
up
Removes backlash
8
A24
Enable “High
Accuracy” Circuit
8
F1000,0
Find edge of Home
Switch at 1000
steps/second
Scan will stop when edge is found
9
A0
Disable Home Circuit
Necessary on monochromators with Home Switch
inside optic chamber. Switch uses IR LED.

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5.3 789A-4 Command Summary
Command
Description
Result(s)
ASCII
DECIMAL
HEX
[SPACE]
32
0x20
Initialize
This command must be entered first after
power-up.
Enables communication with scan controller.
If using a terminal program, pressing the "space
bar" will achieve the same result. The controller will respond with its current firmware version.
[CR]
13
0x0D
Carriage
Return
This command must follow all remaining
commands entered.
If using a terminal program, pressing the "Carriage
Return" or “Enter” key will achieve the same
result.
@
64
0x40
Soft Stop
Causes deceleration to a stop.
^C
3
0x03
Reset
(1) Stops motion.
(2) Sets counter to "0"
(3) Assumes "Idle" state
A0
65, 48
0x41
0x30
Home Switch
Disabled
Default Value
A8
65, 56
0x41
0x38
Home Switch
Enabled
Home Swiched Powered & Ready
A24
65, 50, 52
0x41
0x32
0x34
Home
Accuracy
Circuit
Enabled
Used in final move of a Homing function.
C1
67,49
0x43
0x31
Clear
Erases pre-programmed parameters. Only use when
an unexplainable scanning error has occurred.
F
102
0x66
Find Edge
Used in final phase of Homing. Home switch must
be blocked. Sending “F1000,0” will cause the
motor to move upward at 1000 steps/second until
home switch is cleared.
G
103
0x67
Run Internal
Program
Executes a program stored in non-volatile memory
after entering [G] followed by the program’s
starting address.
I
73
0x49
Starting
Velocity
Starting and stopping speed of scan.

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5.3 789A-4 Command Summary (continued)
Command
Description
Result(s)
ASCII
DECIMAL
HEX
K
75
0x4B
Ramp Slope
Acceleration /deceleration factor. Value less
than 127 will result in both acceleration and
deceleration having the same slope. Entering
2 values will set the acceleration slope to the
first value and the deceleration slope to the
second value. Range = 0-255
P
80
0x50
Enter & Exit
Program Mode
Entering P0 through P1000 sets the 789A-3
into internal program mode. See the manual
supplement for more details.
M
13
0x0D
Move at
constant
velocity
Entering M10000 will cause the motor to
move at 10000 steps/second until hitting a
limit or by sending “@”.
S
83
0x53
Save
Stores parameters to non-volatile memory.
Should be used if parameters had to be re-
entered after "C1" command.
V
86
0x56
Scanning
Velocity
Sets scan speed in steps per second. Range =
36 sps to 60000 sps. (1)
W
87
0x57
Pause
Wait nmilliseconds n= 0 to 65535
Example –W2000 = Pause 2000mS
X
88
0x58
Examine
Parameters
Sends values of "K", "I", and "V" parameters.
Actual values may be slightly different from
entered values. This is due to internal
calibration to system clock oscillator.
]
93
0x5D
Read Limit
Switch Status
0 = No limit encountered.
32 = Home Limit Encountered.
64 = High limit encountered.
128 = Low limit encountered.
+
43
0x2B
Index Scan in
"Up" Direction
+36000 = Scan 36000 steps in upward
direction. This scan usually results in 1 motor
revolution. Max. value = 8388600.
-
45
0x2D
Index Scan in
"Down"
Direction
-36000 = Scan 36000 steps in downward
direction. This scan usually results in 1 motor
revolution. Maximum value = 8388600.
Note 1 = Scanning velocities may not be the exact value entered.

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5.3 789A-4 Command Summary (continued)
Command
DECIMA
L
HEX
Description
Result(s)
^
94
0x5E
Read Moving
Status
0 = No motion detected.
1 = Moving
2 = High in constant velocity.
16 = Slewing - Ramping complete.
5.4 Calculating Velocity Parameter
To calculate motor velocity parameter:
1. Refer to Grating Selection Chart.
2. Locate your Instrument Model and Grating.
3. Note the nM or Å per motor revolution.
Important!
Once you select either nM or Å, you must stay with the your selection throughout the equation!
Remember 1 nM = 10 Å.
4. Unless otherwise stated, the standard motor resolution is 36000 Steps per revolution;
(For example: your instrument is a 2061 with a 1200 G/mm Grating. The nM per
revolution is 4 nM. 4 nM = 36000 motor steps).
5. Divide your desired scan rate by the nM or Å per motor revolution determined earlier.
6. Multiply the result from Step 5 by 36000.
7. Divide the result from Step 6 by 60 to convert from motor steps per minute to pulses per
second.This is the number entered after the “V” (ie: “v12000”).

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5.5 Sample Program
Object:
To scan a Model 207 monochromator with 1200 G/mm grating at a rate of 100
nM/minute over a range of 40 nM, then change direction and slew back to
starting wavelength at a rate of 400 nM/minute.
Program
Line
Command
Description
1
V15000
15,000 steps/sec. (100 nM/min.)
2
+ 360000
40 nM wavelength scan (360,000 steps)
3
W1000
Wait 1000 milliseconds to change velocity
4
V60000
Change V to 60,000 steps/sec. (400 nM/min.)
5
-396000
Change direction and return 396,000 steps
6
+36000
Change direction and increment 36000 steps. These last
two steps eliminate mechanical backlash.

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Appendix
Warranty and Assistance, Warranty Exceptions, and Returning Goods
Warranty and Assistance
McPherson products are warranted to be free from defects in material and workmanship and conform to
the specifications furnished by the company at date of delivery. The company’s obligation under this
warranty is limited to servicing, adjusting, or repairing or replacing any McPherson made part or parts
thereof, returned to the factory or in the field. Shipping or travel expenses to be prepaid by customer both
ways. Items manufactured by McPherson carry a warranty of one year. Purchased items carry the original
manufacturer’s guarantee where available.
McPherson shall not be liable for consequential damages resulting from accidents, alterations, misuse,
improper installation, handling by improperly qualified personnel, operation on low or excessive
voltages, or any use in violation of operating instructions furnished by the company.
If any defect appears upon receipt, the purchaser shall promptly notify the company. No material will be
accepted for repair or replacement without prior authorization from the company. (See instructions for
returning goods on page A-3.) Upon such authorization and in accordance with instructions from the
company, parts, materials or equipment for which repair or replacement is requested shall be returned to
the company for examination, or be examined in the field. Shipping and/or travel charges will be quoted
and must be prepaid by the purchaser. Final determination as to whether a product or part is actually
defective rests with the company.
For parts not subject to warranty or after lapse of warranty period, an estimate of repair charges will be
submitted to the customer before servicing the equipment.
The company reserves the right to make changes or improve its products and will supply such
replacement where available without imposing upon itself the obligation to supply the same in lieu of its
product(s) previously offered and/or manufactured.
This warranty is in lieu of all other obligations or liabilities expressed or declared on the part of the
company. The company neither assumes, nor authorizes any other person to assume for them, other
obligations or liability in connection with the sale of equipment manufactured by McPherson.

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Warranty Exceptions
The warranty will not apply in case of any misuse, neglect of instructions and violations of the policy.
Furthermore, the performance of systems assembled by the customer which incorporate McPherson parts,
supplies or instruments is not covered by this warranty. The following indicate other exceptions to the
one year warranty.
Parts and Supplies —Optics, photomultipliers, MCP PDA, CCD, and other detectors, light sources,
fuses, rubber products (i.e. o-rings, gaskets), quartz capillaries and any other items that can be damaged
by misuse, overexposure and/or are of expendable nature will not be warranted unless received defective
or destroyed by the malfunctioning of warranted components.
Obvious Abuse —Components or assemblies that require replacement or repair due to obvious abuse or
unauthorized repair attempts will not be subject to or considered a warranted item.
This certifies that Model _________________ , S/N __________________ carries a limited warranty of
one year from date of delivery, with above limitations and terms.
This certifies that Model __________________ , S/N _________________ carries a purchased * second
year of limited warranty beginning one year after the original date of delivery, with above limitations and
terms.
______________________________________
*Additional warranties and / or service subject to written quotations and purchase orders.