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

Model 789A-4 Scan Controller
2
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

Model 789A-4 Scan Controller
3
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

Model 789A-4 Scan Controller
4
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.

Model 789A-4 Scan Controller
5
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.

Model 789A-4 Scan Controller
6
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.

Model 789A-4 Scan Controller
7
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

Model 789A-4 Scan Controller
8
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

Model 789A-4 Scan Controller
9
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

Model 789A-4 Scan Controller
10
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