Meinberg SyncBox PTP User Manual

Technical Information

Operating Instructions

SyncBox PTPv2
AHS/DHS

Impressum

Meinberg Funkuhren GmbH & Co. KG
Auf der Landwehr 22
D-31812 Bad Pyrmont

Telefon: [phone] / 9309-0
Telefax: +49 (0) 52 81 / 9309-30

Internet: http://www.meinberg.de
E-Mail: [e-mail]

Bad Pyrmont, den 17. Mai 2010

Table of Contents

Quick Start Guide.......................................................................................................... 5

PTPv2 Slave with high accuracy Oscillator...................................................................6

The Modular System SyncBox...................................................................................... 6

PTP Status LEDs „MST“ und „SLV“....................................................................7

User defined outputs OUT0, OUT1.......................................................................7

Modulated Time Code (IRIG)................................................................................8

Capture Inputs CAP0, CAP1................................................................................. 8

RS232 TERM.........................................................................................................8

Precision Time Protocol (PTP) / IEEE1588v2.............................................................. 9

General Information.............................................................................................10

Functionality in Master Systems.......................................................................... 11

Functionality in Slave Systems............................................................................11

The WEB interface...................................................................................................... 12

Configuration: Main Menu...................................................................................... 13

Configuration: Ethernet........................................................................................... 14

IPv4 addresses and DHCP................................................................................... 14

Configuration: Local................................................................................................15

Configuration: Statistics...........................................................................................16

Statistical Information..........................................................................................16

Configuration: Manual.............................................................................................17

Configuration: PTP.................................................................................................. 18

The Command Line Interface...................................................................................... 20

CLI Ethernet.............................................................................................................21

CLI PTP parameters.................................................................................................22

Attachment: Technical Information.............................................................................23

Technical Specifications.......................................................................................... 23

Front Panel connectors.............................................................................................23

Safety instructions for building-in equipment......................................................... 24

CE-Label.................................................................................................................. 24

Power supply............................................................................................................25

Third party software.................................................................................................26

Operating System GNU/Linux.............................................................................26

Samba...................................................................................................................26

Network Time Protocol Version 4 (NTP)............................................................27

mini_httpd............................................................................................................ 27

GNU General Public License (GPL)....................................................................28

Quick Start Guide

One minute after power up you can connect via a null modem cable a serial
terminal from your PC. While booting the system the green „RDY“ LED is blinking
and switch on permanently if system is ready. You can use e.g. the standard
Hyperterminal program shipped with your Windows operating system. Configure
your terminal program with 38400 Baud, 8 Data bits, no parity and 1 Stop bit. The
terminal emulation have to set to VT100 (press RETURN for first connection):

The login name is always „root“. The password is “timeserver” by factory settings.

Type in the command „setup“ to enter the configuration program. All further settings
can be done with this program:

Choose the „Ethernet“ button to set up the network configuration. To get the time
of an external PTP IEEE1588 grandmaster you have to configure the SyncBox with
an unique IP address and the default gateway. The „MST“ and „SLV“ LEDs reflect
incoming and outgoing PTP packets: the „SLV“ LED will flash green if a valid PTP
packet will receive from an external PTP IEEE1588 grandmaster; the „MST“ LED
will flash if the SyncBox will send a PTP packet to the PTP network. While normal
operation of the SyncBox the „SLV“ LED should be flashing every 2 seconds.

After this all further settings can be done via network interface, either by using a
WEB browser or a Telnet Session.

The outputs of the SyncBox (10MHz, PPS and IRIG) will be enabled if the system
has been synchronized by an external PTP grandmaster once and the internal
oscillator (OCXO HQ) has warmed up. When outputs will be enabled can be set up in
the PTP configuration. The SyncBox will start with a non valid time until it it
synchronized by an external PTP IEEE1588 grandmaster once.

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PTPv2 Slave with high accuracy Oscillator

The SyncBox provides a high precision time base (OCXO HQ) with multiple
outputs for 10MHz, PPS and IRIG via TCP/IP network, synchronized by a PTP
IEEE1588 grandmaster reference clock. The SyncBox act as a PTP slave with high
precision oscillator to produce different timing and frequency outputs. SyncBox is a
set of equipment composed of a PTP IEEE1588 Time Stamp Unit (TSU) and a power
supply, all installed in a metal DIN rail mounted chassis and ready to operate. Two
user configurable outputs for 1 PPS, 10 MHz and unmodulated time code (IRIG) can
be set up next to a modulated time code (IRIG) output. Also two capture inputs are
integrated to get high precision time stamps of external events. A simplified LINUX
operating system is installed on the single-board computers flash disk. After the
network connection has been established the timeserver can also be configured and
monitored remotely from a workstation via TELNET or SSH. An integrated HTTP
server enables access to the SyncBox by using an ordinary WEB browser.

The Modular System SyncBox

The SyncBox is a set of equipment composed of a PTP IEEE1588 Time Stamp
Unit (TSU) and a power supply unit, all installed in a metal rail mount case and ready
to operate. The interfaces provided by the SyncBox are accessible via connectors in
the front panel of the case. Details of the components are described below.

Front View SYNCBOX/AHS

SyncBox has one PTP IEEE1588 network interface. The outputs of the SyncBox
(10MHz, PPS and IRIG) will be enabled if the System has been synchronized by an
external PTP grandmaster once and the internal oscillator (OCXO HQ) has warmed
up. The SyncBox will start with a non valid time until it it synchronized by an
external PTP IEEE1588 gradmaster once. Next to PTP IEEE1588 a the Linux system
supports a number of further network protocols: HTTP(S), SSH and Telnet. Because
of this remote configuration or status requests can come from any WEB browser.

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Changes in the receiver status, errors or other important events are logged on the local
Linux system.

PTP Status LEDs „MST“ und „SLV“

To get the time from a PTP IEEE1588 grandmaster clock a valid IPv4 address and
the gateway have to be set up on the ethernet port. The state of the PTP on the
SyncBox will be reflect by the LEDs „MST“ and „SLV“. the „SLV“ LED will flash
green if a valid PTP paket will receive from an external PTP IEEE1588 grandmaster;
the „MST“ LED will flash if the SyncBox will send a PTP paket to the PTP network.
While normal operation of the SyncBox the „SLV“ LED should be flashing every 2
seconds.

User defined outputs OUT0, OUT1

Both outputs OUT0 and OUT1 can be set to 10 MHz, 1 PPS or unmodulated Time
Code (IRIG) each. The default configuration is:

OUT0: 10 MHz

OUT1: 1 PPS

To change configuration of outputs open a Telnet or SSH session to the SyncBox
and edit the file /mnt/flash/config/ptp/tsu_conf. The type of Time Code will be set for
both outputs and also for the unmodulated output.

# Time Code Types for IRIG Mode:
# 0: B002_B122
# 1: B003_B123
# 2: A002_A132
# 3: A003_A133
# 4: AFNOR
# 5: IEEE1344
# 6: B220_1344
# 7: B222
# 8: B223

IRIG Mode: 4

# Output Modes:
# 0 : Idle
# 1 : 1PPS
# 2 : 10MHz
# 3 : IRIG

OUT0 Mode: 2
OUT1 Mode: 1

OUT0 inverted: 0
OUT1 inverted: 0

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OUT0 active: 1
OUT1 active: 1

When outputs will be enabled can be set up in this file. By default all outputs will be
enabled after booting the SyncBox (LED „ENB“ will flash green). Be aware that the
time of the SyncBox is not valid after reboot until the internal PTP has not
synchronized by an external PTP grandmaster. To enable outputs when the internal
PTP has synchronized and the OCXO HQ has been fine adjusted you have to set the
parameter „OCXO HQ control:“ to „1“. It could take several hours to do the fine
adjusting of the OCXO HQ.

Modulated Time Code (IRIG)

This output will provide a modulated Time Code (IRIG). The type of Time Code is
the same as the outputs OUT0 and OUT1.

Capture Inputs CAP0, CAP1

Two time capture inputs called User Capture 0 and 1 are provided at the front panel
(CAP0 and CAP1) to measure asynchronous time events. A falling TTL slope at one
of these inputs lets the microprocessor save the current real time in its capture buffer.
Before every capture the ports have to be enabled by software. This could be done by
a command from Telnet or SSh session on the SyncBox. The command „show_ucap“
will cyclic enable the capture ports and print the time in nano seconds and the channel
number.

RS232 TERM

To connect a serial terminal use the left RS232 connector in the front panel. Via the
serial terminal connection it possible to configure the SyncBox parameters with the
command line interface. You have to use a NULL-MODEM cable connecting to your
PC or Laptop computer. You can use e.g. the standard Hyperterminal program
shipped with your Windows operating system. Configure your terminal program with
38400 Baud, 8 Databits, no parity and 1 Stopbit. The terminal emulation have to set
to VT100. After connecting to the SYNCBOX there will be displayed the following
message (press RETURN for first connection; default user: root password:
timeserver).

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9

Precision Time Protocol (PTP) / IEEE1588v2

PTP/IEEE1588 is a time synchronization protocol that offers sub-microsecond
accuracy over a standard ethernet connection. This level of accuracy can be reached
by adding a so-called hardware time stamping unit to the network ports that are used
for PTP time synchronization. The time stamping unit captures the exact time when a
PTP synchronization packet is sent or received. These time stamps are taken into
account in order to compensate transfer delays introduced by the ethernet network.

In PTP networks there is only one active source of time, the so-called Grandmaster
Clock. If two or more Grandmaster Clocks exist in one network, a algorithm defined
in the standard is used to find out which one is the „best“ source of time. This „Best
Master Clock“ algorithm has to be implemented on every PTP/IEEE1588 compliant
system and therefore all clients („Slave Clocks“) will select the same Grandmaster.
The other, not selected Grandmaster Clocks will „step back“ and enter passive mode,
meaning that they do not send out synchronization packets as long as that is done by
the selected master.

The installed network infrastructure components play a big role in a PTP network and
directly influence the level of accuracy that can be reached on the clients.
Asymmetric network connections degrade the accuracy, therefore classic layer 2 and 3
ethernet switches with their store and forward technology are not suitable for
PTP/IEEE1588 networks and should be avoided. Simple ethernet hubs, at least the
ones with fixed pass-through times, are no problem. In large networks special
switches with built-in PTP/IEEE1588 functionality help to maintain a good level of
accuracy even over several subnets and longer distances. These components act as so­called „Boundary Clocks“, they compensate their internal packet processing times by
using time stamping units on each port. They synchronize to the Grandmaster Clock
and in turn act as a Grandmaster to the other subnets they are connected to.

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