IOTA ONESHEET 1 OF 20

SAFETY PRECAUTIONSMANUAL – Before attempting to install or operate the unit, read and familiarize
yourself with all of the safety, installation, and operational instructions in thismanual. This manual contains valuable safety, operational, and troubleshooting
information and should be maintained for future reference.
WARNINGS – For personal safety and to insure correct operation of the unit,
know and follow all warnings. In particular, this instrument produces high voltage
spikes. Do not operate the instrument without a valve attached to the instrument
through the supplied cable. Do not connect or disconnect valve or valve cable
while the instrument is operating.
POWER SOURCES – Use only power sources that are within the specified limits
and which are capable of providing the specified power outputs for this unit.
GROUNDING – Make certain that the power source is properly grounded.
DISASSEMBLY – DO NOT attempt to disassemble the unit beyond what is
described in the User's Manual. Disassembly will expose high voltages that
could cause severe electrical shock.

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TABLE OF CONTENTS
Table of Contents
Section 1 General Information
1.1 Scope
1.2 Purpose of equipment
1.3 Description of instrument
1.4 Specifications
1.5 Equipment supplied
1.6 Accessories required but not supplied
1.7 Optional test equipment
Section 2 Installation
2.1 Unpacking
2.2 Installation
2.3 Driver Settings
2.4 Connections
2.5 Checkout
Section 3 Operation
3.1 Front Panel controls and indicators
3.2 Operating modes
3.2.1 Internal one shot
3.2.2 Internal cycle
3.2.2.1 ON/OFF
3.2.2.2 Frequency
3.2.3 External one shot
3.2.4 External cycle
3.3 Memory save/recall
3.4 Remote operation
3.5 Operational notes and limits
Appendix A Differences Between IOTA ONE® Versions
Appendix B Remote Interface Communications Protocol
LIST OF FIGURES
Figure 1.1 View of front panel with functions labeled
Figure 2.1 View of driver board with labeling of burst timing DIP switch andhold in jumpers
Figure 3.1 Screen shot of the remote software GUI application

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SECTION 1
GENERAL INFORMATION
1.1 SCOPE
This manual describes the operation of the IOTA ONE® valve driver instrument,
Parker part number 060-0010-900. This instrument is similar in operation andperformance to the Parker part number 060-0001-900 instrument, but withelectronic displays, increased timing accuracy, and remote operation capability.
For those users familiar with the older 0001 version, Appendix A describes the
major differences between the two.

1.2 PURPOSE OF EQUIPMENT
The IOTA ONE® is a complete system for driving molecular beam pulsed
sources for laser spectroscopy experiments. Supersonic carrier gas pulses for
Helium, Argon, etc. can be controlled in place of “CW”, thus reducing the sizeand cost of high vacuum systems. Synchronizing the gas pulse with the laser
pulse reduces the pumping size, increases the signal to noise ratio and lowers
the temperature. Molecules are cooled without changing to liquid and therefore,
higher peak intensities can be achieved due to the simpler spectra of cold
molecules. Less sample is used.
The IOTA ONE® can be rack mounted or used on a bench. Pulse duration
ranges in microseconds, milliseconds or minutes can be selected. Both ON
TIME and OFF TIME settings can be changed while running. The instrument iscapable of repetition rates up to 250 Hz; however, the valve may not operatecorrectly at higher rates. The unit can be triggered both internally or externallyand has “one shot” capability. Both input and output logic-level (TTL) signals arethrough the front panel BNC jacks.

1.3 DESCRIPTION OF INSTRUMENT
The front panel of the IOTA ONE® is depicted in Figure 1.1. Following is a
description of the controls, indicators, and connectors on the front panel:

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Timing Error LED

On Indicator LED

Off Indicator LED
MemorySave/Recall

On Time Range
On Time Adjustments

Off Time Range
Off Time
Adjustments

Power Switch/
Pilot Light

Mode Select

Valve Jack

External Trigger
and Indicator

Remote Input

Figure 1.1 View of Front Panel Showing Controls, Indicators, and Connectors“ON-TIME” Section
1. INDICATOR – A red LED that lights whenever the valve is open. Note thatthe human eye may not respond to light pulses that are less than 3 milliseconds.
The LED is actually illuminated a few milliseconds longer than the valve is open
so that it can be seen. Because of persistence of vision, the LED may appear toremain on for high repetition rates.

2. DURATION – A four-digit digital display indicates the “ON” (open) time of thevalve reading from 0001 to 9999. Up and down push-button switches below thedisplay permit the user to increment and decrement the value of each digit. Notethat the display automatically carries over to the next digit(s) when incrementing
past 9 and decrementing past 0.
3.
RANGE – Four-position momentary switch/indicators determine the time
range for the “ON-TIME DURATION” switch: microseconds, milliseconds,
seconds, or minutes.
“OFF-TIME” Section
4. INDICATOR – A red LED that lights whenever the valve is closed. Note thatthe human eye may not respond to light pulses that are less than 3 milliseconds.
The LED, therefore, may appear to be off during short off-time durations.
Likewise, for very high repetition rates, the LED may appear to remain on.
5. DURATION – A four-digit digital display indicates the “OFF” (closed) time ofthe valve reading from 000.0 to 999.9. Up and down push-button switches below
SHEET 5 OF 20

the display permit the user to increment and decrement the value of each digit.
Note that the display automatically carries over to the next digit(s) whenincrementing past 9 and decrementing past 0.
6.
RANGE – Four-position momentary switch/indicators determine the time
range (milliseconds, seconds, or minutes) or selects frequency mode for the“OFF-TIME DURATION” switch.
OTHER CONTROLS, INDICATORS, AND CONNECTORS
7. ERROR – A red LED that lights when the operating parameters are set
outside allowable limits.
8.
START -- This momentary contact push button switch starts action in the
INTERNAL mode by triggering a single pulse (ONE SHOT) or starting a seriesof pulses (CYCLE).
9. STOP - This momentary contact push button switch stops any timing that
may be active and restores the valve to the OFF condition. If the instrument is
operating in a mode that is independent of timing (EXTERNAL CYCLE MODE),
this control will have no effect.
10. INTERNAL/EXTERNAL – These four momentary switch/indicators selectthe operating mode and signal sources for the system.
11.
INPUT (TTL) – This BNC jack allows the unit to be triggered from anexternal source. The input signal should be low (0 volts) for off and high (+5volts) for on.
12.
SIGNAL – This green push button/LED serves two functions. As an
indicator, it illuminates to show a logic high on the external signal source. As acontrol, it serves as an input that is active as a signal source. It is active when
depressed.
13.
OUTPUT (TTL) – A logic high (TTL) output is provided at this BNC jackwhenever the valve driving circuit is active in any operating mode.
14. POWER – A retained action switch to control the AC power to the unit. The
face of this switch will illuminate when depressed if proper AC voltage is present
and the fuses are functional.
15. VALVE – This jack is the connection to the valve through the supplied valve
cable.
16.
RS-232 – This jack is the RS-232 connection for remote monitoring andcontrol.

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17.
SAVE -- This momentary push button saves the current settings of the
instrument to non-volatile memory. Upon power up, the instrument loads themost recent SAVE settings.
18.
RECALL – This momentary push button restores the most recent SAVE
settings to the instrument.
On the rear panel of the IOTA ONE® is a power input module with a standard
IEC detachable cord socket for the AC power cord. In addition this module
contains a drawer above the socket that houses the two 5 X 20 mm AC fuses.
AC power requirements as well as fuse size appear on the rear panel as well as
in section 1.4 (Specifications).

1.4 SPECIFICATIONS
Size: Standard 19-inch relay rack, 3U high by 10” deep excluding handles.
Weight: 11pounds.
Voltage input: 90 – 250 VAC, 47 – 63 Hz,
Power consumption: 160VA max.
Fuses (Qty 2): 5 x 20 mm glass cartridge, 2.0 A, 250 V
Power factor: 0.93 min
Operating temperature: 0 to +40 degrees C
Storage temperature: -20 to +60 degrees C
Humidity: 20 – 90 %, non-condensing
Shock and Vibration: As incurred in bench handling.
Logic-Level (TTL) output: one TTL unit load.
Logic-Level (TTL) input: compatible with standard TTL logic.
Valve Burst: 300 V max
Timing accuracy: 250 nanoseconds or 0.001%, whichever is greater.
Timing uncertainty (with respect to external trigger): 250 nanoseconds.

1.5 EQUIPMENT SUPPLIEDThe IOTA ONE® instrument is supplied with the following:
Power cord
Valve cable
IOTA ONE® remote software for PC
This operator's manual

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1.6 ACCESSORIES REQUIRED BUT NOT SUPPLIED
To operate the IOTA ONE® instrument, a Parker valve must be orderedseparately. No additional equipment is required.
In the event of abnormal operation, the instrument should be put into the handsof a qualified technician to troubleshoot the problem.

1.7 OPTIONAL TEST EQUIPMENT
In order to use the external logic-level (TTL) input, an external pulse generator or
push-button switch will be required. If an automated test setup is to be used, this
input can be exercised directly from a computer-controlled logic source.
In order to use the external logic-level (TTL) output, an oscilloscope or othermonitoring equipment will be required. If an automated test setup is to be used,
this output can be monitored directly through a computer-controlled logic input ora data logging device.
In order to use the remote monitor and control feature, a PC with a COM port will
be required. If an automated test setup is to be used, the remote monitor andcontrol functions can be accessed through an RS-232 port implemented in theautomated equipment. A standard DTE/DCE RS-232 cable is required toconnect the instrument to the remote equipment.

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SECTION 2
INSTALLATION
2.1 UNPACKING
Before unpacking the IOTA ONE® , examine the packing container and notify theshipping carrier of any damage. Unpack the contents of the container carefully
and take inventory of the contents. Save the container and the packing material
in the event that the instrument needs to be returned to the factory for servicing.
The following items should be inventoried:
IOTA ONE® instrument
Power cord
Valve cable
IOTA ONE® remote software for PC
This operator's manual
In addition to these items, a valve will be included in the packing container if one
was ordered with the instrument.

2.2 INSTALLATIONThe IOTA ONE® instrument is designed to operate in a bench-top environment or
mounted in a standard 19” relay rack. Rack mounting flanges with standardspaced holes are provided for rack-mounting. To mount the instrument in a rack,use standard rack hardware. Rear support of the instrument is not required.

2.3 DRIVER SETTINGSThe IOTA ONE® embodies a high performance valve driver that reduces theturn-on time of the valve by applying a short high voltage burst to overcome theinductance inherent in the valve coil. Following the high voltage burst, the driver
reduces the voltage to the valve to a value that is lower than the rated voltage ofthe valve, but is sufficient to hold it open. This reduces valve heating andimproves closing response time. Both the time of the burst and the hold involtage can be set by the user using the following procedure:
2.3.1 Turn the unit off and disconnect the power cord to insure that no
dangerous voltages are present inside the instrument.
2.3.2 Remove the top cover by taking out the two screws on the back panel andsliding the cover to the rear.

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2.3.3 The instrument is factory set for a burst pulse length of 180 microseconds.
To change the burst pulse length, find the 8-position DIP switch as designated on
Figure 2.1. The base (minimum) length is 50 microseconds. Setting one ormore of the DIP switches OFF adds to this base time setting. The values of theswitches are as follows:
Switch #(microseconds)
1
2
3
4
5
6
7
8

Value
100
100
100
80
40
20
10
5

Burst Timing Dip Switch
Hold in Jumper

Pilot light Connector
IRF 8404001

IRF 540

Figure 2.1
Locations of Burst Timing DIP Switch and Hold In Jumper on Driver Board
The standard setting has switches 1, 6, and 7 OFF for a total pulse length of 180
microseconds. This setting has been found to be sufficient to operate most pulse
valves consistently. Valves having an orifice larger than 1.0 mm and/or operating
at higher pressure differentials (greater than 100 PSIG) may require a longer
SHEET 10 OF 20

high voltage pulse to operate correctly. Ideally, the setting should be as short as
possible while still yielding consistent results. The maximum setting should notexceed 320 microseconds.
2.3.4 The holding voltage for the valve is also set on the driver PC board with a
4-position jumper as depicted in Figure 2.1. It is marked for 12-, 20-, 24-, and28-volt valves. The standard factory setting is the 28 volt position. Normally thejumper would be set for the coil voltage of the valve, but some valves meetingthe conditions set forth above may require that the jumper be set for a lower
voltage to prevent the valve from closing at the end of the high voltage pulse.
2.3.5 After making required adjustments to the driver board, replace the cover
before reconnecting it to AC power.
DANGER
Do not attempt to apply power to the instrument with the cover removed, as highvoltages are exposed that could cause severe electrical shock

2.4 CONNECTIONS
Attach one end of the supplied valve cable to the valve and the other end to thefront panel jack labeled “VALVE.” Note that the cable is polarized at both ends
and therefore can only be attached one way.
Once the driver and valve are connected, attach the AC line cord to the rear of
the unit and plug into electrical current with the proper voltage.

DANGER
When the unit is in operation, the driver triggers the valve with a pulse of
approximately 275 volts (Direct Current). DO NOT operate the instrument
without a valve properly attached.

2.5 CHECKOUT
2.5.1 With the instrument connected as in section 2.4, depress the power switch
in the upper right corner of the front panel. The button should illuminate as wellas the panel displays indicating that power is present. If the button and displays
do not illuminate, check that the instrument is connected to a live AC source withthe proper voltage. Once that is verified, disconnect the power and remove thefuse holder tray on the rear panel. Replace the fuses with the correct size andtype as specified in section 1.4. Reconnect the power and repeat this paragraph.

SHEET 11 OF 20

If the power indicator still fails to illuminate, place the instrument into the hands ofa qualified technician to troubleshoot the problem.
2.5.2 Referring to section 1.3 as required, set the instrument to the following
state:ON TIME
0040 Milliseconds
OFF TIME 040.0 Milliseconds
MODE
Internal Cycle
Depress the START button. The ON TIME and OFF TIME indicators should
alternately flash and the valve should emit an audible sound at a 12.5 Hz rate.
Depress the STOP button to shut down the cycling. To more completely verify
the instrument and to familiarize yourself with its operation, refer to section 3.2.

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SECTION 3
OPERATION
3.1 FRONT PANEL CONTROLS AND INDICATORSThe front panel controls, indicators, and connectors of the IOTA ONE® aredescribed in section 1.3 and are depicted in Figure 1.1.

3.2 OPERATING MODES
The IOTA ONE® Pulse Driver unit has four operating modes selected bydepressing one of the four buttons below the START and STOP buttons just rightof center on the front panel. The selected mode will be indicated by the
associated button illuminating.
3.2.1 INTERNAL ONE SHOT – One activating pulse whose length is determinedby the ON TIME section will be directed to the external pulse valve each time the
START button is pressed. Longer pulses may be aborted by pressing the STOP
button. Note that START button debounce circuits are implemented to produce
exactly one pulse in INTERNAL ONE SHOT mode if depressed and released
quickly. To produce a single pulse, the button must be depressed and released
within 400 milliseconds. Holding the button down will produce a repeatedretriggering at 400 millisecond intervals. Timing between successive pulses
cannot be less than 400 milliseconds using this mode. If such timing is required,
INTERNAL CYCLE or one of the EXTERNAL modes can be used. In this mode,
the OFF TIME is not used and the OFF TIME display is dimmed.
3.2.2 INTERNAL CYCLE – A train of pulses will be started when the START
button is pressed and aborted when the STOP button is pressed. There are two
ways to set up the INTERNAL CYCLE mode, ON/OFF and FREQUENCY.
3.2.2.1 INTERNAL CYCLE, ON/OFF – If the OFF TIME RANGE selected ismilliseconds, seconds, or minutes, the ON TIME section determines the open
time of the valve, and the OFF TIME section determines the interval between
valve actuations. The period of of the cycle is the combined times and thefrequency is (1 / period).
3.2.2.2 INTERNAL CYCLE, FREQUENCY – If the OFF TIME RANGE selected
is FREQ, the ON TIME section determines the open time of the valve, and the
OFF TIME section determines the frequency. In this mode of operation, there
may be a small error in the actual frequency due to the granularity of the OFF
timers. The instrument calculates the period and subtracts the ON TIME to
determine the nearest OFF TIME to achieve a frequency close to the frequency
entered.

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3.2.3 EXTERNAL ONE SHOT – When the EXT INPUT TTL is high or the
SIGNAL button is depressed, the OFF TIMER will be triggered. When the OFF
TIMER times out, the ON TIMER will be triggered. If the OFF TIMER is set to000.0 or if FREQ mode is selected, there will be no delay between the trigger
and the ON TIMER trigger. The EXTERNAL input is level triggered, not edge
triggered, so that the trigger pulse width must be less than the OFF TIMER
setting. The START button does not function in this mode; however, the STOP
button can be used to abort the timers after they have been triggered.
3.2.4 EXTERNAL CYCLE – In this mode the valve will open whenever the EXT
INPUT TTL is high or the SIGNAL button is depressed. Likewise, it will close
whenever a logic low is applied to the INPUT jack and the SIGNAL button is notdepressed. The START and STOP buttons do not function and all pulse
parameters are controlled by the external signal source. In this mode, the ON
TIME and OFF TIME functions are not used and the displays are dimmed.

3.3 MEMORY SAVE/RECALLSAVE -- This momentary push button will save the current settings of the
instrument to non-volatile memory. Upon power up, the instrument will load themost recent SAVE settings.
RECALL – This momentary push button will restore the most recent SAVE
settings to the instrument.
The SAVE function can be used to establish a temporary default setting that canbe restored at any time or upon power up.

3.4 REMOTE OPERATIONThe IOTA ONE® has the capability of remote operation over an RS-232 data link.
The protocol for the link is described in Appendix B, and a GUI application for PC
is supplied with the instrument. A Windows® -based PC with a COM port and astandard DB-9 DTE/DCE cable are required to operate the instrument remotelyusing the supplied GUI application. A PC that has no COM port can also be
used with a standard USB/serial interface adapter.
To operate the IOTA ONE® remotely, install the supplied application on the PC
and connect the PC COM port to the RS-232 connector on the instrument with a
DB-9 cable. Launch the application to see the GUI interface, which resembles
the front panel of the instrument, with a few additions. See Figure 3.1 for ascreen shot of the GUI as it should appear.

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Figure 3.1 Screen shot of GUI Application for Remote Operation
The fields in the GUI labeled ON TIME, OFF TIME, MODE, START, STOP,
SAVE, and RESTORE are similar to the same fields on the front panel of the
instrument and are described in section 3. (Note that RESTORE on the GUI isequivalent to the RECALL button on the instrument.) The remaining parts of the
GUI are described below.
The SELECT PORT pull-down menu is used to select the COM port of the PC towhich the instrument is connected. The correct COM port must be selected
before any communications with the instrument can be established.
The GUI can be used to either control the instrument or to monitor it. These twobasic modes are selected with the Radio Buttons in the CONTROL group:
When IOTA ONE is selected, the GUI is in the monitor mode and clicking on the
UPDATE button will update the GUI screen to match the front panel of the
instrument. When REMOTE is selected, the control mode is selected andclicking on the UPDATE button will update the front panel of the instrument tomatch the GUI screen. Note that the START, STOP, SAVE, and RESTORE
buttons are active regardless of which CONTROL button is selected.
The ID push button initiates an Identify command to the instrument. The
instrument will respond with a response string of “{AIWMA091}e”. This commandprovides a means of checking communications integrity.

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The FILE OPERATIONS permit the user to SAVE and LOAD instrument settings
to the PC hard drive. These operations use the GUI display as the source for
SAVE operations and the destination for the LOAD operations, so the following
procedures must be followed to save/load a file from/to the instrument:

SAVE INSTRUMENT SETTINGTO FILELOAD SETTING TO
INSTRUMENT FROM FILE

Select IOTA ONE from the Control group Click on LOAD to get a pop-up window
Click on UPDATE
Select the folder of the file to load
Click on SAVE to get a pop-up window
Select the file to load
Select the desired destination folder
Click on OK
Enter a file name
Select REMOTE from the Control group
Click on OK
Click on UPDATEThe ON time—microseconds and OFF time—microseconds text fields display the
ON and OFF times respectively, calculated from the settings on the GUI display.
These are provided as a reference check and may be useful in determining
granularity errors in FREQ mode.
The Command/Response Strings text field displays the actual strings ofcharacters sent to and received from the instrument. This information can be
useful as a guide when setting up automated testing. For an explanation ofthese strings, refer to Appendix B.

3.5 OPERATIONAL NOTES AND LIMITSThe various modes of the Iota One make use of the ON and OFF timers
differently. When modes are selected that do not make use of a timer, thedisplay for the associated timer is dimmed, indicating that the display has nofunction in that mode. A description of the modes follows:
1. INTERNAL ONE SHOT: ON timer only is used, triggered by START button.
2. INTERNAL CYCLE: ON and OFF timers are used, ON timer is triggered by
START button.
3. EXTERNAL ONE SHOT: ON and OFF timers are used, OFF timer is triggeredby EXT button or positive level on TTL INPUT, ON timer is triggered at the end of
the OFF time.
4. EXTERNAL CYCLE: Neither timer is used, valve driver is actuated by EXT
button or high logic level on TTL INPUT.
EXT button will illuminate whenever it is depressed or whenever a positive signal
is present on the TTL INPUT.
The TTL OUTPUT will have a logic high signal present whenever the valve isdriven (open).

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The UP and DOWN buttons for the digits are debounced with a 300 millisecond
timer. Holding a button down continuously will result in multiple commands,
repeated at 300 millisecond intervals. Each of the two four-digit displays isequipped with logic that automatically carries to and borrows from the digit to its
left when a 0/9 roll-over occurs. This function is carried for successive digits
throughout the display, such that incrementing a 9999 display results in a displayof 0000. Likewise, decrementing a display of 0000 by one results in a display of9999.
The START button debounce circuits are implemented to produce exactly one
pulse in INTERNAL ONE SHOT mode if depressed and released quickly. To
produce a single pulse, the button must be depressed and released within 400
milliseconds. Holding the button down will produce a repeated retriggering at
400 millisecond intervals. Timing between the start of successive pulses cannot
be less than 400 milliseconds using this mode. If such timing is required,
INTERNAL CYCLE or one of the EXTERNAL modes can be used.
The EXTERNAL input is not debounced to permit full use of that input for the
EXTERNAL CYLE mode. In the EXTERNAL ONE SHOT mode, the length of theexternal input has some restrictions for deterministic results:
1. If the OFF time (delay) is not set to zero, the length of the EXTERNAL input
must be less than the OFF time.
2. If the OFF time (delay) is set to zero, the length of the EXTERNAL input mustbe less than the ON time.
When using the EXTERNAL ONE SHOT mode with a manual input and shortpulses, the OFF time should be set for several hundred milliseconds or greater
so that it will serve a debounce function. As long as the input pulse is less thanthe OFF time, the ON time will have no restriction.
The following conditions will cause the ERROR LED on the panel to illuminate:
1. A zero ON time for INTERNAL ONE SHOT, INTERNAL CYCLE, and
EXTERNAL ONE SHOT modes.
2. A zero FREQUENCY input in INTERNAL CYCLE mode.
3. A value of ON time greater than the period when the FREQUENCY range isselected in INTERNAL CYCLE mode.
4. Any set of conditions in INTERNAL CYCLE mode that will result in afrequency greater than 250 pulses per second.
5. A zero off time in INTERNAL CYCLE mode.
The ON TIME indicator is illuminated a few milliseconds longer than the pulse
duration so that extremely short ON times can be seen.

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APPENDIX A
DIFFERENCES BETWEEN IOTA ONE® VERSIONSThe IOTA ONE® valve driver instrument (known today as Parker part number
060-0001-900) was first introduced in the 1980s and has been in production
since its introduction with minor changes. The most notable change was aredesign in the driver board in 1993, but very little has been done to affect theuser interface. In 2015, a revised controller was introduced (Parker part number
060-0010-900), which is similar in operation and performance to the original
instrument, but with electronic displays. This section describes the majordifferences between the two versions of the controller as it affects the user.
Original Version

Electronic Display Version

All mechanical switches for numericalentry assure power up parameters tobe the same as those prior to power
down.

SAVE button must be used to establish
power up conditions.

Microprocessor timing incurs latency in Programmable logic running at a higher
timing and limits timing accuracy.
clock rate has no latency and yields
triggering stability within 250
nanoseconds.
Duty cycle of internal cycle mode islimited to 50%. Two error indicators
are used.

There is no limit on duty cycle. One
error indicator is used with slightly
different criteria. See section 3.3.

STOP button is required to reload timer No reset is required when changing
parameters when changing modes.
modes.
ON TIME indicator does not show short ON TIME indication is extended a few
pulses.
milliseconds to show short pulses.
Numerical entry embodies a featurethat permits borrowing and carrying topreceding digits.
START button and EXT inputs havedebounce circuits that differ fromoriginal version. See section 3.3.
Remote monitor and control capability
are provided, permitting automatedoperation and saving of test setup
parameters to a PC.

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APPENDIX BREMOTE INTERFACE COMMUNICATIONS PROTOCOL
GENERAL
The communications standard is RS-232 interface, compatible with the COM port
on a PC.
BAUD 19200
8 DATA BITS
ONE START BIT
NO FLOW CONTROLONE STOP BITNO PARITY
All communications to the instrument are in the form of a command sent by thehost controller, followed by a response from the IOTA ONE® . All characters inboth the command and the response strings are defined as ASCII printable,
shown as bold characters. The command and response structures are the sameand are shown below.

{@ + command character + data string + } + checksum
The command character is always echoed in the response string. The data
string will differ for the command and response strings. The command
characters and data strings for both command and response are listed under
COMMAND DEFINITIONS below.
The checksum is calculated from ascii values of the string of characters prior tothe checksum as follows:
Subtract 32 from the ascii value of each character and add the results.
Perform modulo 95 on the resultant sum.
Add 32 to the results of the modulo operation.
This is the checksum byte and will always be an ascii printable character.
COMMAND DEFINITIONS
Numbers in parentheses are decimal values of ASCII characters.
(73): Device Identifier "I". The command data field will be null. The response data
field will consist of six ASCII characters. This data field is: “WMA091” This
command has no effect on the operation of the IOTA ONE®.
(70): Full Control "F". The command data field will contain 11 bytes in the orderdefined below. The response data field will be in the same format as thecommand data field. The command will change the operating parameters of the
IOTA ONE® to match those of the command string.
BYTE LIMITS
1(48) – (57)2(48) – (57)SHEET 19 OF 20

MEANINGFirst digit (MSD)of On Time
Second digit of On Time

3
4
5
6
7
8
9
10
11

(48) – (57)(48) – (57)(48) – (51)(48) – (57)(48) – (57)(48) – (57)(48) – (57)(48) – (51)(48) – (51)Third digit of On Time
Fourth digit (LSD) of On Time
Range of On Time, in numerical order as shown on panel
First digit (MSD) of Off Time
Second digit of Off Time
Third digit of Off Time
Fourth digit (LSD)of Off Time
Range of Off Time, in numerical order as shown on panel
Mode, in numerical order as shown on panel.

(71): Start "G". This command performs the same function as the START buttonon the panel of the IOTA ONE®. The command data field will be null. The
response data field will be in the same format as the Full Control command data
field.
(72): Stop "H". This command performs the same function as the STOP buttonon the panel of the IOTA ONE®. The command data field will be null. The
response data field will be in the same format as the Full Control command data
field.
(87): Write to NV "W". This command writes the current operating parameters of
the IOTA ONE® to the non-volatile memory. The command data field will be null.
The response data field will be in the same format as the Full Control commanddata field.
(92): Restore from NV "R". This command recalls the data stored in non-volatilememory to the IOTA ONE®. The command data field will be null. The response
data field will be in the same format as the Full Control command data field.
(83): Status "S". The command data field will be null. The response data field will
be in the same format as the Full Control command data field. This command
has no effect on the operation of the IOTA ONE®.

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