Arroyo Instruments ComboPak 685 Series User Manual Download

Page: 23 / 52

685 Series

ComboPak

User’s Manua

l · Page 23

Using the Laser Driver

Laser Control Modes

The

ComboPak

offers five laser control modes:

Io (ACC)

Io HiBW (ACC)

(AMC)

Po (APC)

, and

Vf (AVC)

Changing the control mode can only be done through the computer interface,

either through

Arroyo Control

, or by sending the

appropriate LASER:MODE

command.

and

Io HiBW

modes (referred to collectively as ACC, or automatic current

control modes) are used to drive a specific current through the laser diode.

When in this mode, the set point will be in milliamps, and the

ComboPak

will

drive the desired current through the laser diode as long as the voltage at the

chosen set point does not exceed the voltage limit. In

mode, you will be

limited to less than a 10 Hz bandwidth. To modulate above that rate, use the

HiBW

, which is a high bandwidth current mode supporting modulation. For

improved noise performance in high bandwidth mode, the analog filter can be

enabled, see

Analog Filter

below for more details.

mode (also referred to as AMC, or automatic monitor photodiode control,

mode) is used to control the laser diode using the monitor diode feedback. You

select the target monitor diode current, and the

ComboPak

will drive exactly

enough forward current through the laser diode to generate the selected monitor

diode current. Only low frequency modulation (10Hz or less) is possible in

mode due to the feedback latencies of the photodiode itself.

mode (also referred to as APC, or automatic power control, mode) is simply

mode with a mathematical constant applied to the set point, providing a

convenient way of operating in milliwatts. Using the

PD Resp

factor (in

A/mW),

set point is internally converted to an equivalent

set point by the driver,

which is then used to control the photodiode feedback. For example, if the

Resp

factor was 10, then a set point of 1mW would be the same as a set point of

mode (also referred to as AVC, or automatic voltage control, mode) is used to

control the voltage driven through the device. Unlike ACC mode, AVC mode

allows the current to drive to whatever current is necessary to achieve the

voltage set point, so long as it does not exceed the current limit. As with

mode, only low frequency modulation (10Hz or less) is possible in

mode.

Summary of Contents for ComboPak 685 Series

Page 1: ......

Page 2: ... Control Modes 23 Using the Laser Limits 24 Analog Modulation 24 Compensating for Voltage Loss 25 Using the Temperature Controller 29 TEC Control Modes 29 Using the TEC Limits 29 Selecting the Fixture 29 Working With Thermistors 30 External Fan Control 31 Resistive Heaters and Heat Cool Only Modes 32 Gain Control and the PID Loop 32 Using the AutoTune Function 33 Compensating for TEC Cable Resista...

Page 3: ...ications that do not have a computer interface The ComboPak offers all the features you would expect from a modern precision laser controller including Laser driver o 10ppm current stability o 100mA to 2A current ranges o Comprehensive laser protection circuitry including hardware voltage and current limits o External analog modulation o Power mode control both in photodiode current AMC or compute...

Page 4: ...installation 1600 10K 10kΩ Thermistor Accurate to 0 2 C 1200 NULL RS 232 NULL Cable 2m 1201 USB Cable 3m Safety Terms and Symbols The following safety related terms are used in this manual Warnings noted by the WARNING heading explain dangers that could result in physical injury or death Cautions noted by the CAUTION heading explain conditions that could result in damage to the instrument other eq...

Page 5: ... Please see the Service section later in this manual for instructions on how to obtain service for this instrument WARNING To avoid electrical shock ensure a 3 prong power cord is used and is plugged into a earth grounded receptacle Failure to do so can result in severe injury or death WARNING Potentially lethal voltages exist within this instrument This instrument is intended for use by qualified...

Page 6: ...ents of your laser and TEC In the Laser tab o Current limit set just above the maximum operating current of your laser o Voltage limit set 0 5V above the maximum laser voltage In the TEC tab o ITE current limit set to the maximum TEC current o Temperature low limit 5 degrees below the lowest operating point o Temperature high limit 5 degrees above the highest operating point o Gain start with 5 or...

Page 7: ...s to find the ideal value and for even finer control you can set the Gain to PID and directly set the PID control values Continue reading for more detailed operating and installation instructions Installation Installation of the ComboPak is very straightforward as the quick start section above illustrated This section will provide additional details and considerations for installing your ComboPak ...

Page 8: ...e used with LaserPak and TECPak instruments in a mixed use configuration Warm up and Environmental Considerations In order to achieve the highest level of accuracy the ComboPak should be powered on for at least one hour prior to taking measurements In addition ensure that the unit is not operating outside the operational temperature range or humidity conditions CAUTION Do not operate the unit abov...

Page 9: ...Control Modes section below the unit offers five control modes Io ACC Io HiBW ACC Im AMC Po APC and Vf AVC Change this setting to select a new mode Io ACC LAS MODE Io limit This setting controls the maximum amount of forward current that can be delivered to the laser diode This limit is implemented in hardware for immediate response For more information about limits see Using the Laser Limits belo...

Page 10: ...rt from monitor photodiode current into optical power The value is in terms of microamps per milliwatt μA mW such that power photodiode current divided by the factor 0 00μA mW LAS CALPD Tol Time Tolerance time is the amount of time in seconds that the measured value current voltage etc must be within the set point the tolerance for the unit to be considered in tolerance In Io modes the tolerance i...

Page 11: ...ond more quickly to the difference between the set point and the actual temperature while a lower value will cause it to respond more slowly Select PID for direct access to the PID parameters Read more on setting gain below 30 TEC GAIN PID P The proportional term of the PID loop Will only be available if Gain is set to PID 1 TEC P PID I The integral term of the PID loop Will only be available if G...

Page 12: ...h Lim R High Lim is the sensor high limit If operating in R Mode and the actual sensor measurement exceeds this value the output will be turned off R limits are not monitored in Ite Mode Limit monitoring can also be disabled in software see TEC ENAB OUTOFF command 45kΩ TEC LIM RHI Tol Time Tolerance time is the amount of time in seconds that the actual temperature must be within the set point temp...

Page 13: ...inutes to delay turning off the fan after the TEC output has been turned off See the External Fan Control section below for more information 5 minutes TEC FAN Cable R The resistance of the cable and connectors in ohms This setting allows for accurate voltage measurement at the TEC by removing the voltage loss of the cable 0 0080Ω TEC CABLER T Rate Selects a desired temperature ramp rate in degrees...

Page 14: ...iption Factory Default Computer Command Terminal Mode Terminal mode simply echoes any characters received over the serial or USB interfaces No TERMINAL Msg Term This controls the output message termination and can be set to CR LF CR LF or None CR LF TERM ...

Page 15: ...cable is required for both the TEC and Laser outputs Arroyo Instruments carries cables specifically designed for these applications both with a DB connector on the device end or with a bare wire pigtail for terminating the connection into a custom mount or device Function DB to DB p n DB to Pigtail p n Laser 1220B 1221B TEC 1260B 1261B CAUTION The interlock connections must be kept isolated from a...

Page 16: ...2 Interlock 3 Earth Ground 4 Laser Cathode Voltage Sense 5 Laser Cathode 6 Photodiode PD Cathode 7 Photodiode PD Anode 8 Laser Anode Voltage Sense 9 Laser Anode Shell Earth Ground Laser Output Connector DB 9 Female Arroyo Instruments has followed industry conventions for laser DB 9 connections and is compatible with pin outs from other vendors such as ILX and Newport However care should still be t...

Page 17: ... Description 1 2 9 TE 3 4 10 TE 5 6 Earth Ground 7 Sensor 8 Sensor 11 Fan 12 Fan 13 thru 15 Reserved no connect Shell Earth Ground TEC Output Connector DB 15 Female ComboPak IPC and Control Connectors LEDs Input Power Connector IPC The Input Power Connector IPC accept a IEC 60320 C13 power cord the same type of power cord used with most computers ...

Page 18: ... as the auxiliary power supply The modulation input provides a separate negative ground reference pin 6 which should only be used with the modulation signal The control interface is described in detail in the Using the Control Interface section below Modulation Input The modulation input is made on pins 5 and 6 of the Control I O connector and accepts a 0 10V input signal for analog set point cont...

Page 19: ...on potential wiring issue is the first item where the laser has the anode or cathode connected to earth ground and one of the signals on the Control I O is also earth grounded such as the modulation source or the digital I O pins This causes a ground path through the laser module that at a minimum can disrupt proper operation of the ComboPak or at worst damage your laser In situations like this yo...

Page 20: ...Properties dialog appears choose the Hardware tab then click on the Device Manager button When the Device Manager appears click on the plus sign to the left of Ports The port identified as a USB Serial Port is the ComboPak In the event you have multiple Arroyo Instruments products plugged in simultaneously you will need to experiment to see which instrument was assigned to which port Arroyo Contro...

Page 21: ...he driver will always respond by turning the output off and generating an E 537 error message in an overload condition Lower current models 1 Amp and below have no risk of thermal overload For the TEC section the ComboPak will automatically protect itself by lowering the TEC current until it is no longer in an overload condition This may lower the deliverable power to your TEC but it will prevent ...

Page 22: ... s Manual 0 1 2 3 4 0 0 0 5 1 0 1 5 2 0 2 5 3 0 TEC Voltage Volts TEC Current Amps TEC Safe Operating Range for 685 ComboPak Operating Zone Any combination of current and voltage that lie in this zone is acceptable Non Operating Zone ...

Page 23: ...or photodiode control mode is used to control the laser diode using the monitor diode feedback You select the target monitor diode current and the ComboPak will drive exactly enough forward current through the laser diode to generate the selected monitor diode current Only low frequency modulation 10Hz or less is possible in Im mode due to the feedback latencies of the photodiode itself Po mode al...

Page 24: ...e second to trigger when these conditions occur and therefore should not be relied on to provide fast protection of the laser diode Analog Modulation The instrument supports external analog modulation using the modulation pins on the analog interface connector Modulation rates vary by model so see your model s specification for the maximum modulation rates Only Io HiBW mode supports high speed mod...

Page 25: ...pensating for Voltage Loss All cables and connectors have a small but measurable resistance When driving current through them this resistance causes a voltage loss in the cable and if not compensated for will result in errors in laser or LED voltage measurement In many cases this is not a problem as highly accurate voltage measurement are typically not required and the error can be ignored However...

Page 26: ...rated Once the warning is generated it will not be generated again until the output is turned off and back on Using remote voltage sense is very simple First connect pin 4 of the Laser Output DB 9 to the laser cathode and pin 8 to the laser anode then in the menu set Vf Sense to Remote LASER VSENSE 1 Indicated voltage will now be the remote diode voltage When using remote voltage sense any Cable R...

Page 27: ...divide the set point by 1000 before using it in this equation Short the Connection at the End of the Cable A second method which does not require a DMM and can be done with just the ComboPak itself is to short the anode and cathode wires at the end of the cable nearest the laser diode drive current through the cable and note the measured laser voltage LASER LDV The resistance is found using a simp...

Page 28: ... for Vf Limit is always the voltage at the connector except when using remote voltage sense see above This means that the Vf Limit must take into account all the voltage required including the cable loss i e the voltage measured if the Cable R value were zero 2 Cable R is ignored in Vf mode This means that the set point and measured voltage are always the voltages at the connector and Cable R is n...

Page 29: ... for your sensor Using the TEC Limits The ComboPak supports three different types of limits temperature sensor and TEC current There is both a temperature high and temperature low limit and if the actual temperature exceeds either of these limits the output will be shut off Likewise both high and low limits exist for the sensor R limits and the output will be shut off if the sensor measurement exc...

Page 30: ... thermistor works by translating temperature into resistance with resistance decreasing as temperature increases hence the negative coefficient Here is a typical response curve of a thermistor Typical Resistance vs Temperature Graph As can be seen on the graph the resistance of the thermistor drops very quickly In the typical control range 0 C to 40 C 10K thermistors offer good sensitivity to chan...

Page 31: ...stor A 1 12924x10 3 B 2 34108x10 4 C 0 87755x10 7 You can change the coefficients using the TEC CONST command External Fan Control The ComboPak has a built in user adjustable 4 12V DC power supply designed to provide up to 250mA to an external fan such as those built into the 200 and 240 Series Series LaserMounts When using the ComboPak with mounts that require a fan no additional external power s...

Page 32: ...olers as resistive heaters will heat regardless of the direction of current To change the cooling mode use the TEC HEATCOOL command Gain Control and the PID Loop The ComboPak supports a fully configurable PID loop allowing full customization of the PID control parameters To simplify control eight standard gain settings are defined and many applications can achieve acceptable performance with these...

Page 33: ...not necessarily the ideal PID parameters and improvements may be possible by further refining the results manually Before starting the AutoTune function it is best to begin from ambient conditions either with the TEC off and the mount stabilized at ambient or the TEC on and the set point around ambient temperature 23 C While this starting point is not required it can produce better results AutoTun...

Page 34: ...to stabilize with the new P and D parameters The second step begins which is the determination of the I term This completes around 200 seconds into the test and then the output stabilizes with the calculated set of PID parameters for the remaining portion of the graph If the AutoTune process fails the instrument will generate an E 436 AutoTune Failed error message and turn the output off Any of th...

Page 35: ...oltage measurement The safest method of calculating cable resistance is to short the ITE and ITE connections making sure whatever you are using to short the terminals is not itself adding resistance to the circuit Use short heavy gauge wires preferably soldered onto the terminals to minimize any resistance the short might add Place the short as close to the Peltier as is reasonable A simple approa...

Page 36: ... wish to calibrate 2 Enable user calibration editing using the TEC USERCAL EDIT or LASER USERCAL EDIT command 3 Update the user calibration data using the TEC USERCAL PUT or LASER USERCAL PUT command The above is a very abbreviated list of commands See the LASER USERCAL and TEC USERCAL commands in the Computer Interfacing Manual for more detail For each set point or measurement there is a correspo...

Page 37: ...need to adjust the offset value for the high range Io set point which is index 2 Considering that you need to raise the set point by 1 4mA then index should be adjusted to 1 4mA The command would look like LASER USERCAL PUT 2 1 1 4 This will compensate the set point by increasing it 1 4mA and bring it closer to 300 0mA The measurement adjustment is similar but in this case you need to adjust index...

Page 38: ... set point calibration you would have the following two calculations Slope 300 100 298 6 101 5 200 197 1 1 0147 slightly rounded Offset 100 1 0147 101 5 2 9934 You can validate your calculations by applying the formula to one or both of the data points to confirm the compensation is correct Consider the 300mA set point if we apply the values just calculated we should get a compensation that increa...

Page 39: ...ate the laser current to within 0 1mA then your meter would have an accuracy of 0 025mA or better Using lower accuracy meters could actually degrade the accuracy of the instrument rather than improve it Considerations for Calibrating the Laser Current For current calibration many meters have poor current measurement performance A alternate approach is to measure the voltage across a known resistor...

Page 40: ... Accuracy set μA 0 05 1 Stability ppm time 200 24 hours Temperature Coeff ppm C 200 PD Bias V 2 5V fixed LASER VOLTAGE Range V 0 10 0 3 5 Resolution V 0 001 Accuracy set V 0 05 0 005 Stability ppm time 50 1 hour Temperature Coeff ppm C 100 EXTERNAL MODULATION Input Range 0 10V 10kΩ Modulation Bandwidth kHz 150 100 100 100 MEASUREMENT LASER CURRENT Resolution mA 0 005 0 02 0 05 0 1 Accuracy set mA ...

Page 41: ...S CURRENT Resolution mA 10 Accuracy mA 40 GENERAL Laser Connector DB 9 female TEC Connector DB 15 female Fan Supply 4 12V 350mA max Computer Interface USB 2 0 Full Speed Type B Power 50 60 Hz 90 240V 60W Size H x W x D inches mm 2 6 66 x 4 5 114 3 x 8 5 215 excluding connectors Operating Temperature 10 C to 40 C Humidity 70 relative humidity non condensing Storage Temperature 20 C to 60 C 1 Softwa...

Page 42: ...Page 42 685 Series ComboPak User s Manual Mechanical Drawings ...

Page 43: ...o parse the message the data was in an invalid format USB Serial only E 204 Suffix not valid An invalid number base suffix radix was encountered when parsing a number USB Serial only E 217 Recall bin failed A storage bin recall failed because an invalid bin number specified or nothing in bin E 218 Save bin failed A save to a storage bin failed likely due to an invalid bin number E 220 Script save ...

Page 44: ...was turned off E 416 Cal failed An error occurred during calibration that caused the calibration to fail The unit is no longer in calibration mode E 419 TEC not stable The TEC is considered stable if the temperature has changed less than 0 02 C for more than 20 seconds E 433 Not a TEC The TEC CHAN command attempted to select a non TEC channel E 434 ITE limit exceeds cable rating The cable plugged ...

Page 45: ...in the OUTOFF register was set E 508 TEC off disabled output The laser output was turned off because the TEC was off and the corresponding bit in the OUTOFF register was set E 509 Laser short circuit disabled output The laser output was turned off because a short condition was detected and the corresponding bit in the OUTOFF register was set E 510 Laser out of tolerance disabled output The laser o...

Page 46: ...ails E 538 Internal sensor limit output off The auxiliary sensor resistance value exceeds the limits output turned off E 539 Internal temperature limit output off The auxiliary temperature exceeds the limits output turned off I 700 User save successful User save to bin successful I 701 User recall successful User recall of bin successful I 703 Laser usercal reset The user calibration constants for...

Page 47: ... thru E 997 Hardware specific error occurred A hardware error was detected Contact factory for support in diagnosing this problem E 998 Command not supported A command was recognized but not supported by the ComboPak E 999 Non specific error A non specific error was encountered ...

Page 48: ...ating as specified on the unit as replacements If after replacing the fuse it continues to blow immediately discontinue use of the instrument and contact your local Arroyo Instruments representative or the factory for support Service Service and repair for the ComboPak can be obtained by contacting the distributor from where you purchased the instrument or directly from Arroyo Instruments A comple...

Page 49: ...ght prepaid to the indicated service facility Repairs will be made and the instrument returned freight prepaid Repaired products are warranted for the balance of the original warranty period or 90 days whichever first occurs Limitation of Warranty The above warranties do not apply to products which have been repaired or modified without Arroyo Instruments written approval or products subjected to ...

Page 50: ...1326 1 2013 Immunity EN 61000 4 2 2009 Electrostatic Discharge EN 61000 4 3 2010 Radiated Immunity EN 61000 4 4 2012 Electrical Fast Transients Burst EN 61000 4 5 2014 Surges EN 61000 4 6 2014 Conducted Immunity EN 61000 4 11 2004 Supply Dips and Variations Under 2014 35 EU In accordance with EN 61010 1 2010 This Certificate is the Manufacturer s Declaration which states that the 685 Series ComboP...

Page 51: ...urrent emissions In accordance with EN 61326 1 2013 Immunity EN 61000 4 2 2009 Electrostatic Discharge EN 61000 4 3 2010 Radiated Immunity EN 61000 4 4 2012 Electrical Fast Transients Burst EN 61000 4 5 2014 Surges EN 61000 4 6 2014 Conducted Immunity EN 61000 4 11 2004 Supply Dips and Variations Under Electrical Equipment Safety Regulations 2016 In accordance with EN 61010 1 2010 This Certificate...

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