TEM PhaseLock User manual

PhaseLockManual
TEM Messtechnik GmbH
December 8, 2022
TEM Messtechnik GmbH
Grosser Hillen 38
D-30559 Hannover
Tel: [phone]
Fax: [phone]
E-mail: mailto:[e-mail]
URL: http://www.TEM-Messtechnik.de

PhaseLockManual
Contents
1 Product description 5
1.1 General......................................... 5
1.2 Functionalcomponents ................................ 5
2 Safety Instructions 7
3 Scope of delivery 9
3.1 Mandatorycomponents ................................ 9
3.2 Components for standard (MCPC) configuration . . . . . . . . . . . . . . . . . . . 9
3.3 Optionalparts ..................................... 9
3.4 Alternativeparts.................................... 9
4 Brief description of the control elements 10
4.1 Frontpanelelements.................................. 10
4.2 Rearpanelelements .................................. 13
4.3 Touchscreen...................................... 15
4.3.1 Displaysettings ................................ 15
5 Installation 16
5.1 Placement ....................................... 16
5.2 MainsConnection ................................... 16
5.3 Alternative DC power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.4 ConnectiontoPC ................................... 16
6 Getting started 17
6.1 Overview........................................ 17
6.2 Using the PC visualization software “Kangoo” . . . . . . . . . . . . . . . . . . . . 17
6.3 Inputsignalconnections................................ 18
6.4 Output signal connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.5 Outputsignalrange .................................. 21
6.6 Switchthedeviceon.................................. 22
6.7 InputSignalMonitor.................................. 22
6.8 InputSignalAdjustment................................ 24
6.9 Outputsignalcheck .................................. 25
6.9.1 Check and adjustment of the actuator at output B (HV out 2) . . . . . . . 25
6.9.2 Check of the actuator at output A (HV out 1) . . . . . . . . . . . . . . . . 26
6.10 Taking the PID regulator A into operation . . . . . . . . . . . . . . . . . . . . . . 27
6.11 Optimizing the PID regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.12 Taking the PID regulator B into operation . . . . . . . . . . . . . . . . . . . . . . 30
6.13 Loss of input signal and hold mode . . . . . . . . . . . . . . . . . . . . . . . . . . 32
6.14Automaticsearchmode ................................ 32
7 Operation 35
CONTENTS 3 / 60

PhaseLockManual
8 Detailed description 37
8.1 FrequencyMixer.................................... 37
8.2 Signalmonitor ..................................... 38
8.2.1 Analog monitor signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
8.2.2 TTLoutput .................................. 39
9 Software Installation 39
9.1 Installation of the Kangoo Software . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.2 Installation of LabView Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.3 InstallingtheUSBDrivers............................... 41
9.4 UpgradingtheFirmware................................ 42
10 Communication interface 43
10.1Communicationsyntax................................. 43
10.2Variables........................................ 45
10.3Inputsettings ..................................... 45
10.4 Quadrature signal analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
10.5Monitorsettings .................................... 46
10.6 Regulator (servo loop) settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.7Outputsettings .................................... 48
10.8 ”Search for signal” settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
10.9Stepresponsesettings................................. 48
10.10Scansettings...................................... 49
10.11Triggersettings .................................... 50
10.12Motordriversettings.................................. 51
10.13Ditherlocksettings .................................. 52
10.14Measurementsettings ................................. 53
10.15Systeminformation .................................. 53
11 Electrical Specifications 54
11.1TechnicalData..................................... 54
11.2MainsPowerCable................................... 55
11.3HD-15Connector ................................... 55
12 Delivery Content 56
13 Customer Service 56
4 / 60 CONTENTS

PhaseLockManual
1 Product description
1.1 General
PhaseLock is a general electronic device for the set-up of a phase-locked loop (PLL). It synchronizes
the pulse train of a laser with an electronic reference clock or with another laser (see figure 1).
PhaseLock comprises a phase comparator unit for two periodic RF (radio frequency) input signals
and two PID controllers as well as a logic section that eases the locking and re-locking. High voltage
amplifiers for PZT actuators and a micro stepping motor driver are available as add-ons.
PhaseLock well applies for:
 Stabilization of the repetition frequency and pulse timing of pulsed lasers
 Control of the pulse envelope phase (carrier offset frequency) of femtosecond lasers
 Stabilization of frequency or phase of electronic oscillators
Phase locking of the optical frequency of continuous-wave (cw) lasers was reportedly accomplished
successfully.
1.2 Functional components
PhaseLock combines all components required or beneficial for this purpose in a user-friendly compact
device:
 multi cycle phase comparator
 input section for signal conditioning
 independent PID regulators, adapted especially to resonant systems like piezo-driven optical
components
 output amplifier, user-selectable as high-voltage amplifier for piezo actuators, or as low-voltage
amplifier generating a control signal for external amplifier sections
 logic section for automatic recognition of successful locking
Figure 1: PhaseLock principle of operation
1 PRODUCT DESCRIPTION 5 / 60

PhaseLockManual
The PhaseLock block diagram is shown in Figures 2 and 3, which gives a first overview on the
function blocks, the relation of the function blocks to each other, the switching options, as well as
the inputs and outputs of PhaseLock.
AVR32 core
user interface
system bus
PID regulator A
P,I,D
DAC
Signal Processor
AVR32 System Control
offset
gain
USB
output A
set
point
PID regulator B
P,I,D
DAC
output B
HV out 1
HV out 2
HV Amplifier
-10 ... 10V
-10 ... 10V
0 ... 150V
0 ... 150V
input
phase,
cycle
counter
signals &
supply
Frequency Mixer
2
3
1
monitor
monitor 2
monitor 1
trigger out
90°
shift
RFLO
X
Y
Pin 1: Input X (-1V...1V)
Pin 2: Input Y (-1V...1V)
ADCs
Figure 2: Schematic block diagram of PhaseLock digital device with MCPC option
6 / 60 1 PRODUCT DESCRIPTION

PhaseLockManual
AVR32 core
user interface
system bus
PID regulator A
P,I,D
DAC
Signal Processor
AVR32 System Control
offset
gain
USB
output A
set
point
PID regulator B
P,I,D
DAC
output B
HV out 1
HV out 2
HV Amplifier
-10 ... 10V
-10 ... 10V
0 ... 150V
0 ... 150V
input
phase,
cycle
counter
signals &
supply
Frequency Mixer
2
3
1
monitor
monitor 2
monitor 1
trigger out
RFLO
ADC
Pin 1: Input (-1V...1V)
Figure 3: Schematic block diagram of PhaseLock digital device without MCPC option
2 Safety Instructions
Before operating the PhaseLock, please read this user guide carefully in order to avoid any damage
of the device or connected equipment as well as any injury to persons.
CAUTION! The PhaseLock device is intended for laboratory use only. The PhaseLock device
should be operated by trained personnel.
CAUTION! The PhaseLock device is used with lasers emitting visible or invisible radiation. Do
not stare into the laser beam! Take precautions to avoid exposure of direct or reflected laser radiation.
CAUTION! The user is responsible for keeping the legal rules concerning laser safety that apply in
their country. In Germany, this is the “Unfallverhtungsvorschrift BGV B2” of the “Berufsgenossen-
schaft der Feinmechanik und Elektrotechnik”.
CAUTION! Use only the supplied power adapter and plugs or the corresponding ones for your
country, as only this guarantees safe operation and grounding of the device.
CAUTION! The PhaseLock is intended for indoor operation with a temperature range of +10◦C
to +40◦C. Do not subject to heat, direct sunlight or the influence of other electric devices. Protect
from humidity, dust, aggressive liquids and vapors.
2 SAFETY INSTRUCTIONS 7 / 60

PhaseLockManual
CAUTION! The PhaseLock should be opened by trained technical personnel only. Before opening
the housing, the device must be disconnected from the supply voltage, for example by pulling the
power plug.
Please keep this manual within easy reach to refer to if needed. Give your PhaseLock to third parties
only with this manual.
8 / 60 2 SAFETY INSTRUCTIONS

PhaseLockManual
3 Scope of delivery
Please check first of all if you obtained all the parts listed below. If not, please check your ordering
form and refer to the manufacturer or distributor.
We recommend to keep the packaging material for future storage and transportation.
3.1 Mandatory components
 PhaseLock electronics in desktop or 19” rack case
 Country specific power cord
 USB A – B cable
 USB memory stick containing PC software
 This manual
3.2 Components for standard (MCPC) configuration
The following parts come with the PhaseLock electronics for use with pulsed lasers (standard appli-
cation). They are omitted for optical phase stabilization of cw lasers.
 RF mixer unit
 15-pole cable with high density Sub-D connectors (male – female)
3.3 Optional parts
Upon explicit order, the following components are integral parts of the PhaseLock electronics
 High voltage amplifier for PZT actuators
 Driver for a stepping motor
3.4 Alternative parts
The low voltage supplied version of PhaseLock comes with an external AC-to-DC converter power
supply (mains adapter) 12W DC, min. 30W.
3 SCOPE OF DELIVERY 9 / 60

PhaseLockManual
4 Brief description of the control elements
4.1 Front panel elements
reset
prgm
vol
A
B
output Boutput A
PhaseLock
input
monitor 1 monitor 2trigger out
digital
locked
in clip
searching
out clip
7
12
11
14
9
810
13
16
15
1
2
3
4
5
6
Figure 4: Front panel elements
Nr. Description
1 4.3” TFT touch screen
2 Loudspeaker volume potentiometer
3 Programmer button. Only used for flashing firmware to the microcontroller.
4 Reset button. Resets the microcontroller.
5 Rotary knob B. To change the digital place when editing a numerical value, turn the wheel while keeping
it pressed.
6 Rotary knob A. To change the digital place when editing a numerical value, turn the wheel while keeping
it pressed.
7 LED “locked”. Turns on whenever the error signal of all enabled regulators is within a small range
8 LED “input clip”. Indicates a large input signal (above +0.9 V or below -0.9V on input a, b or above
+9 V or below -9V on input c, d)
9 LED “searching”. Turns on when one of the regulators is searching for a valid lock point
10 LED “out clip”. Turns on when one of the regulators reaches the limit of its output range
11 “input” HD15 Socket. Feedback measurement input for the mixer product quadrature signal (not used
if mixer is installed in device case)
12 “trigger out” BNC plug
13 “monitor 1” BNC plug. Can be used for observation of internal signals
14 “monitor 2” BNC plug. Can be used for observation of internal signals
15 “output A” BNC plug. Regulator output signal (low voltage: -10V...+10V). For HV amp output see
rear side
16 ”output B” BNC plug. Regulator output signal (low voltage: -10V...+10V). For HV amp output see
rear side.
10 / 60 4 BRIEF DESCRIPTION OF THE CONTROL ELEMENTS

PhaseLockManual
vol
Rx
A
prgmreset
USB B
Tx
AVR32 System Control
3
4
5
6 8
7
1
2
on
off
power
Supply
2
1
HV out 1
HV out 2
HV Amplifier
power down
overheat
2
13
out clip
search
in clip
locked
input
Signal
Processor
monitor 1
trigger
monitor 2
output A
output B
2 4
3
1
Mixer
local oscillator
50 Ω
optical input
850 ... 1650 nm
Figure 5: Front panel elements 19” rack case
Nr. Description
Module: “Supply”
1 Power on LED
2 Primary power switch (another primary power switch and the fuse holder are located on the rear side!)
Module: “Mixer”
This module contains the mixer electronics. The contruction and the front panel elements may vary
depending on the mixer architecture and application requirements. For more details, please refer to
chapter “Mixer”. In standard configuration, the mixer electronics are located in a separate case.
Module: “Signal Processor”
1 Status indicator LEDs:
 LED “locked”. Turns on whenever the error signal of all enabled regulators is within a small
range
 LED “input clip”. Indicates a large input signal (above 95%)
 LED “searching”. Turns on when one of the regulators is searching for a valid lock point
 LED “out clip”. Turns on when one of the regulators reaches the limit of the output range
2 “PD input” HD15 Socket. Feedback measurement input
3 Output BNC plugs:
 “monitor 1” BNC plug. Can be used for observation of internal signals.
 “monitor 2” BNC plug. Can be used for observation of internal signals.
 “output A” BNC plug. Regulator output signal (low voltage: -10V...+10V). For HV amp output
see module “HV Amplifier”.
 ”output B” BNC plug. Regulator output signal (low voltage: -10V...+10V). For HV amp output
see module “HV Amplifier”.
4 “trigger out” BNC plug
Module: “HV Amplifier (optional)”
4 BRIEF DESCRIPTION OF THE CONTROL ELEMENTS 11 / 60

PhaseLockManual
1 “overheat” red LED: if the HV amp stage is overheated, this red LED is on, and the output voltage is
switched off
2 “power down” red LED: this LED is on, when the amplifier voltage is disabled due to overheating or
overcurrent
3 HV output BNC plugs (HV out 1 and HV out 2) for e.g. piezo actuators
Module: “AVR32 System Control”
1 USB connector
2 USB data transmit (green) / USB data receive (red) LEDs
3 Reset button. Resets the microcontroller.
4 Programmer button. Only used for flashing firmware on the microcontroller.
5 Loudspeaker volume potentiometer
6 Rotary knob A
7 Rotary knob B
8 4.3” TFT touch screen
12 / 60 4 BRIEF DESCRIPTION OF THE CONTROL ELEMENTS

PhaseLockManual
4.2 Rear panel elements
Before opening
disconnect mains
power
USB
TEM Messtechnik GmbH
Grosser Hillen 38
30559 Hannover, Germany
www.TEM-Messtechnik.de
HV ready
HV enable
AC 115 V
3.15 A T
AC 230 V
1.6 A T
50-60 Hz
LAN
overheat
power down
HIGH VOLTAGE
CAUTION do not cover
HV out 1HV out 2
230V
12345678 9 10 11 12
Figure 6: Rear panel elements (standard and HV version)
Nr. Description
1 (only with HV option) “HV enable” green LED: The voltage from the HV supply has been applied to
the amplifier stage
2 (only with HV option) “HV ready” green LED: HV supply module is powered on
3 “power” green LED: Power-on indicator
4 AC power socket with primary switch and fuse holder
5 USB connector
6 (only with HV option) bicolor LED: output voltage indicator for HV out 2(green: actual output voltage
high, red: actual output voltage low)
7 (only with HV option) high voltage output channel 2 BNC jack (corresponding to output B signal)
8 (optional) Ethernet LAN connector (RJ-45)
9 (only with HV option) bicolor LED: output voltage indicator for HV out 1(green: actual output voltage
high, red: actual output voltage low)
10 (only with HV option) high voltage output channel 1 BNC jack (corresponding to output A signal)
11 “power down” red LED: This LED is lit when the amplifier voltage is disabled due to overheating or
overcurrent
12 “overheat” red LED: Lit, if the HV amp stage is overheated and the output voltage is switched off.
4 BRIEF DESCRIPTION OF THE CONTROL ELEMENTS 13 / 60

PhaseLockManual
power
USB
TEM Messtechnik GmbH
Grosser Hillen 38
30559 Hannover, Germany
www.TEM-Messtechnik.de LAN
DC 9...36V
aux
overheatpower down
HIGH VOLTAGE
CAUTION
do not cover
HV out 1
HV out 2
1234567 8 9 10 11
Figure 7: Rear panel elements (DC12V version)
Nr. Description
1 “aux” HD15 Socket. Auxiliary connector for special functions.
2 “power” green LED: power on indicator
3 5.5 x 2.5 mm DC power supply plug (voltage range 9...36 V)
4 USB connector
5 (only with HV option) bicolor LED: output voltage indicator for HV out 2 (green: actual output voltage
high, red: actual output voltage low)
6 (only with HV option) high voltage output channel 2 BNC jack (corresponding to output B signal)
7 (optional) Ethernet LAN connector (RJ-45)
8 (only with HV option) bicolor LED: output voltage indicator for HV out 1(green: actual output voltage
high, red: actual output voltage low)
9 (only with HV option) high voltage output channel 1 BNC jack (corresponding to output A signal)
10 “power down” red LED: This LED is lit when the amplifier voltage is disabled due to overheating or
overcurrent
11 “overheat” red LED: Lit, if the HV amp stage is overheated and the output voltage is switched off.
14 / 60 4 BRIEF DESCRIPTION OF THE CONTROL ELEMENTS

PhaseLockManual
4.3 Touch screen
4.3.1 Display settings
To adjust display settings like LED backlight brightness or screensaver settings go to (menu →
miscellaneous →display settings)
Backlight brightness
The brightness of the LED backlight can be adjusted in 10 steps e.g. to avoid bright display illumi-
nation in dark rooms.
Screensaver
When displaying a static image for long periods of time the LCD displays can create a permanent
ghost-like image. A static picture burns into the display and degrades the image quality. To prevent
this burn-in effect the display becomes white after an adjustable delay time. You can return to the
menu by touching the display.
4 BRIEF DESCRIPTION OF THE CONTROL ELEMENTS 15 / 60

PhaseLockManual
5 Installation
5.1 Placement
Place PhaseLock suitably, taking into account the safety warnings in chapter 2.
5.2 Mains Connection
PhaseLock has an IEC power socket at the rear side (unless otherwise ordered, see section 5.3). Use
the delivered power cord for connection to the AC mains. If country-specific cables are required use
high quality power cords, fitting to the local power supply outlets. PhaseLock accepts AC power
supply in a wide voltage range (100. . . 240V AC). The primary mains switch and the fuse holder are
located next to the IEC socket at the rear side. For fuse rating, see label next to the holder.
5.3 Alternative DC power supply
Upon special order, PhaseLock may be equipped with a DC supply socket instead of the AC power
supply. In that case, use the AC-to-DC converter power supply (”mains adapter”) delivered with
the PhaseLock. Alternatively, any other standard DC power supply with voltage from 12. . . 24 V
and minimum 30 W power rating may be used. The connector must have 5.5mm outer and 2.5mm
inner diameter, plus pole at the inner contact. Please note that no primary switch nor a fuse holder
are present for the DC supply. The device will start up right after the connection has been made.
5.4 Connection to PC
PhaseLock can work completely as a stand-alone device. However, you might find it helpful to use
the ”Kangoo” software for visualization and set up of parameters. If you wish to connect PhaseLock
to a PC, use the delivered USB cable. For software and driver installation refer to section 9.
16 / 60 5 INSTALLATION

PhaseLockManual
6 Getting started
6.1 Overview
The following sections describe how to take PhaseLock into operation from the beginning, step by
step. These chapters can be used for becoming acquainted with PhaseLock, as well as for function
testing of the device. It is strongly recommended to read through chapter 4 on page 10 first. A
detailed description will follow later in this manual. Please have a 2-channel oscilloscope with at
least 10 MHz input bandwidth at hand. An analog oscilloscope is a good choice, but if you use a
digital one, make sure the sampling rate is at least 10 MHz to avoid aliasing effects. Start with the
PhaseLock installed according to section 5 and switched off.
6.2 Using the PC visualization software “Kangoo”
Even though the PhaseLock device can work completely as a stand-alone device, it is very helpful
and strongly recommended to use “Kangoo” for visualization and set-up of parameters. If you wish
to operate PhaseLock by the frontpanel touch screen, just proceed with section 6.3. All explanations
will be given for software and front panel operation, as far as both are available.
If ”Kangoo” has not yet been installed on your computer, please follow the instructions in chapter
9 on software and driver installation.
Connect the PhaseLock to the PC by means of a standard USB (A-B) cable. (Please avoid cables
longer than three meters, especially if strong electromagnetic fields are present in your environment).
The device will appear as “TEM uC Virtual Com Port” in the device manager of your computer.
Figure 8: COM Port in the device manager (left) and corresponding COM port settings in Kangoo (right)
Start the Kangoo software and type F5 (or go to Communication →COM parameters) to open the
interface dialog (compare fig. 8). Click to “check!” in the COM Parameters windows to search for
available COM ports. The COM number of PhaseLock should appear in the drop down list next to
6 GETTING STARTED 17 / 60

PhaseLockManual
the button. The port settings like baud rate, data bits und parity settings are important for “real”
COM ports e.g. RS-232. They will be ignored for USB connections.
To test the communication click ”show COM window” in the dialog. Click into the window named
”COM-Terminal” and press ‘ENTER‘. The device should answer with ”no command. . . ” (compare
fig. 9).
Figure 9: COM Terminal window
Later on, you may use this terminal window to learn how to control your device by simple ASCII
commands. Just try and enter ”hello” followed by the ’ENTER’ key . . .
6.3 Input signal connections
PhaseLock requires two high-frequency input signals: First, the photo diode signal representing the
laser’s pulse train (preferably bandpass filtered). Second, a sinusoidal reference frequency signal
(named ”LO” = local oscillator). This may be a synchrotron clock, an RF signal from a synthesizer
or another laser, e.g.. The mixer unit converts the high frequency input signals into a low-frequency
signal (so-called intermediate signal) containing the information about the frequency and phase
difference of the input signals. Operation of the PhaseLock requires the LO frequency to equal the
repetition frequency of the laser or an integer multiple thereof (a harmonic of the pulse signal):
fLO =n∗frep, n = 1,2,3, ... (1)
Example: If the laser repetition frequency can be adjusted in the range 80.00. . . 80.10 MHz, the LO
frequency should be chosen fLO =80.05 MHz or fLO =160.1 MHz or fLO =240.15 and so on.
Set the LO signal to an amplitude of approximately 1Vpp. (The mixer circuit accepts LO signals in
a power range of 0...7 dBm at 50Ω, corresponding to 0.3...1.5Vpp.) Connect the LO signal to the
SMA connector ”LO in” located at the face side of the mixer, see figure 10.
18 / 60 6 GETTING STARTED

PhaseLockManual
(delay in)
(delay out)
RF
LO
fLO
n·fREP
(sinusoid 0...7dBm)
Amplified photo diode
+ optional bandpass filter
Reference oscillator
Optional delay cable
(see text)
Figure 10: Frequency mixer module and its RF connections
Connect the photodiode signal to the SMA connector ”RF” located at the face side of the mixer,
see figure 10. Please make sure that the bandwidth of the photodiode is at least as high as the
chosen LO frequency. If higher harmonics are used (n >= 2), we recommend to insert a suitable
bandpass filter between the photodiode and the mixer. The purpose of the filter is to suppress all
but the nth harmonic in photodiode signal.
All SMA connectors have an impedance of 50Ω. Please make sure that both signal sources (photo-
diode and local oscillator) as well as the interconnecting cables are matched to this impedance.
Note that the MCPC version of the mixer contains a delay cable the length of which is matched to
a certain LO frequency that was defined upon order. That frequency value is noted on the face side
of the mixer. (If you ordered a mixer for a wide frequency range, the delay cable must be chosen
according to the LO frequency. In this case connect the appropriate cable to the SMA connectors
”delay in” and ”delay out” located at the face side of the mixer, see figure 10. Please refer to
chapter 8.1 for details on this topic.)
The intermediate signal is transferred to the signal processor via the 15-pole Sub-D connector. Con-
nect the frequency mixer to the 15-pole ”input” connector of the PhaseLock device (see figure 11).
Please note that the amplitude of the signals inside the mixer is adjusted remotely by the PhaseLock
’s signal processor. Therefore, this connection must be made before power up.
During the installation process, several signals in the signal path must be checked for their shape
and size. For this end, connect an oscilloscope to the BNC jacks “monitor 1, 2” on the front panel
- see figure 11). (The location of the monitor BNC connectors on 19” rack case are shown in figure
5.) Set the input sensitivity of the oscilloscope channels to 2 V/div and remove / switch off any
50 Ω matching resistor!
MCPC option only: If possible, switch the oscilloscope to the X–Y display mode.
6.4 Output signal connections
PhaseLock has up to three outputs to control the laser: two voltage outputs (”output A” and
”output B” on the front panel) and one optional motor driver accessible from the rear side. If a high
voltage amplifier is installed, amplified copies of the output A and output B voltages are available
6 GETTING STARTED 19 / 60

PhaseLockManual
CHX:2V= CHY:2V=
20kS/s
X Y
1MW1MW
(delay in)
(delay out)
RF
LO
fLO
n·fREP
(sinusoid 0...7dBm)
Amplified photo diode
+ optional bandpass filter
Reference oscillator
Oscilloscope
Figure 11: PhaseLock input and monitor wiring scheme
20 / 60 6 GETTING STARTED