Meinberg FDM511 User Manual

Technical Information

Operating Instructions

FDM511

Impressum

Meinberg Funkuhren GmbH & Co. KG
Lange Wand 9
D-31812 Bad Pyrmont

Phone: [phone] / 9309-0
Fax: [phone] / 9309-30

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

May 29, 2009

Table of Contents

Impressum ............................................................................................ 2

Features of the Frequency Deviation Monitor FDM511 ....................... 5

Functional Principle..................................................................... 5

The Front Panel Layout............................................................... 6

LED PL Time .................................................................... 6

LED REF Time ................................................................. 6

LED Fail ............................................................................ 6

LED Overflow................................................................... 6

Push Buttons ...................................................................... 6

Display............................................................................... 6

Analog Outputs ........................................................................... 7

Serial COM Ports ........................................................................ 7

EEPROM .................................................................................... 7

Installation ............................................................................................ 7

Power Supply .............................................................................. 7

Input Signals................................................................................ 7

Powering Up the System ............................................................. 8

The Menus in Detail ............................................................................. 8

Menu Frequency ......................................................................... 8

Menu Frequency Deviation ......................................................... 9

Menu REF Time ......................................................................... 9

Menu PL Time ............................................................................ 9

Menu Time Deviation ................................................................. 9

Menu SETUP............................................................................ 10

Menu Nominal Frequency......................................................... 10

Menu Time Deviation Init ......................................................... 11

Menu COM Parameter .............................................................. 11

Menu Output String................................................................... 12

Menu Analog Outputs ............................................................... 12

Menu Error Bits......................................................................... 13

Menu Serial Number ................................................................. 13

Serial Output Strings ........................................................................... 14

Standard FDM String ................................................................ 14

Short FDM String...................................................................... 15

Time Deviation Preset String..................................................... 15

Areva FDM String .................................................................... 16

Over Range Condition .............................................................. 16

Time Deviation Preset ............................................................... 17

Firmware Updates .............................................................................. 18

CE Label ............................................................................................ 18

Technical Specifications FDM511 ..................................................... 20

Time Strings .............................................................................. 21

Format of the Meinberg Standard Time String................. 21

Format of the Uni Erlangen Time String.......................... 22

Rear Connector Pin Descriptions .............................................. 24

Rear Connector Pin Descriptions .............................................. 25

Features of the Frequency Deviation Monitor FDM511

The module FDM511 was designed to calculate and monitor the frequency in 50/60Hz
power line networks. A preconnected reference is necessary that provides a high
accuracy 10MHz clock, a serial time string and a PPS (pulse per second). In addition to
the frequency, the time is calculated that would be displayed by a clock using the mains
frequency as its timekeeping reference (PLT = Power Line Time). The accumulated
differece between the drifting power line time PLT and the high accuracy reference time
REF is called the time deviation (TD). Because the time deviation has the long-term
accuracy of the reference, it is suitable to supervise the frequency stability. The time
deviation can be read out either via serial interface or via one of the two integrated analog
outputs for further evaluation or regulation.

Functional Principle

The power line frequency to be monitored is applied via the rear VG edge connector
(optional: via a mains socket in the frontpanel) of the FDM511, then filtered and
transformed. After that the sine-wave signal is converted into a TTL signal using a
schmitt trigger. The rising edge of this TTL signal is used to start/stop a counter that is
clocked by the high accuracy 10MHz pulse of the reference. Due to this, the period
length of the mains frequency is measured with a resolution of 100ns and read out by the
micro controller of the FDM511. The values are averaged over a period of one second
and then the frequency is calculated with a resolution of 1mHz.

Calculation of the power line time PLT occurs by counting the periods of the mains
frequency. Depending on the nominal frequency, the PLT seconds are incremented after
counting 50 or 60 periods. To initialize the PLT, it is necessary to get the exact time via
the serial interface (REF) and the pulse per second (PPS) from the preconnected
reference. The time deviation TD is calculated once per second and is limited to ±100
seconds.

5

The Front Panel Layout

The 61mm wide front panel contains four LED indicators, two push buttons and a 8-digit
alphanumerical LED display.

LED PL Time

This LED toggles once per second when the mains
frequency is detected correctly. It stops toggling as
soon as the mains frequency fails.

LED REF Time

This LED toggles once per second corresponding to
the pulse per second of the reference. It stops togg­ling as soon as the PPS is not applied any longer.

LED Fail

This LED is switched on whenever a correct
operation of the module is not ensured and the
results are useless. Loss of the PPS, the mains
frequency or the serial time string can cause this.
The reason for the fault can be found out by reading
the Error-Bits.

LED Overflow

This LED is switched on whenever one of the measurements exceeds its limits:

- Time Deviation is more than ±100 seconds

- Frequency is below 45Hz or above 65Hz

- Analog Output exceeds ±2,5V

The LED is switched off again as soon as all values are back within their limits.

Push Buttons

Measurement and status information can be selected to be shown on the display using the
two push buttons. The Menu button is used to skip to several sub menus while the Set
button is used to select the corresponding item and display its content. In the setup menu
the push buttons are also used to change the configuration of the FDM511 or to enter
parameters.

Display

The 8-digit alphanumerical LED display shows the measurements of the FDM511 like
frequency and time deviation. Furthermore, in the setup menu the display is used to show
configuration parameters and status information.

6

Analog Outputs

FDM511 provides two analog outputs for longtime-recording. These outputs have a
range of -2.5V ... +2.5V, divided in 65536 steps. Either the frequency deviation or the
time deviation can be selected for monitoring via one of these analog outputs.

Serial COM Ports

The frequency deviation monitor provides two serial RS-232 interfaces, COM0 and
COM1. Both ports are able to spread the calculated measurements of the FDM511 once
per second, the format of the string can be selected. In addition, COM0 is used for some
serial commands sent to the module, e.g. for setting a time deviation preset value.
Firmware updates are also possible using this port. The serial input of COM1 is used to
read in the time information of the preconnected reference.

EEPROM

The non-volatile EEPROM is used to store the settings of the FDM511. This ensures a
proper restart without any new configuration after the module was switched off for a
certain time. The two push bottons in the front panel and the LED display are used to set
the parameters (see "Menu SETUP").

Installation

Power Supply

FDM511 needs a single supply voltage of +5V/150mA. As soon as the power supply
and the requested input signals are applied, the module starts operation.

Input Signals

The following input signals, provided by a preconnected reference, are necessary for
operation of the frequency deviation monitor FDM511:

a) 10MHz oscillator clock, TTL level, rear edge connector pin Z12
b) pulse per second, TTL level (active-high), rear edge connector pin D6
c) time string, RS-232, rear edge connector pin B10 (RxD1)

A GPS receiver GPS170 or a DCF77 radio clock PZF511 can be used as a reference, for
example.

7

Powering Up the System

If all the input signals, the power supply and the power line to be monitored have been
connected to the FDM511, the system is ready to operate. The "Fail"-LED as well as the
"Overflow"-LED are switched on after power up reset. FDM511 waits for the incoming
serial time string via COM1 to initialize the internal system time (REF time). When this is
done, the PL time is also initialized with the REF time and consequently, the time
deviation TD is set to +00.000s. From now on the REF time is incremented with the PPS
applied while the PL time is incremented by a certain number of recorded mains
frequency periods (50 or 60). The "PL" and "REF"-LEDs start toggling once per
second, corresponding to their time base. The Fail LED is switched off.

The Menus in Detail

After power-up, the type of the module and the firmware revision is displayed for a short
time. Successively, the following items appear before the display begins to shows the
mains frequency automatically:

Knowledge of the firmware revision is helpful whenever technical support from
Meinberg is needed. The Menu button is used to skip to the menus described in the
following. The corresponding content of the menu is displayed after selection is done
with the Set button.

Menu Frequency

The actual calculated mains frequency is displayed with a resolution of 0.001Hz. This is
the default content of the display after powering-up the module.

8

Menu Frequency Deviation

This menu, choosen with the Set button, shows the deviation of the mains frequency
from the nominal frequency (50 of 60Hz). The frequency deviation is a signed value
with the same resolution and accuracy of the mains frequency.

Menu REF Time

The time, provided by the reference, is shown in this menu.

Menu PL Time

The power line time is displayed when this menu is selected. The PL time is set to the
REF time after a power-up reset and thereafter is clocked with the mains frequency as its
timekeeping reference. Therefore, time jumps, like changeover in daylight saving or leap
seconds, will not be executed!

Menu Time Deviation

The time deviation is the difference between the exact REF time and the drifting PL time.
The displayed value is signed, has a resolution of 1ms and is limited to its maximum of
±99.999s. If this limit is exceeded, an error bit is set (see "Error Bits") and the
"Overflow"-LED is switched on. The time deviation is set to +00.000s after power-up
reset, but can be set to any preset value via the Setup Menu "TD Init". The long-term
accuracy of the time deviation is equal to the pulse per second from the reference.

9

Menu SETUP

The setup menu allows the configuration of the FDM511. To avoid the erroneous
change of these parameters, it is not possible to skip to the submenus by pressing the
Menu button. Rather than before, the setup submenus will be released not before the Set
button is pressed for at least one second and the character '*' appears behind the text
"SETUP".

Thereafter, the Menu button is used to show all available setup submenus that can be
entered for configuration with the Set button as descibed before. Successively the
following setup menus appear when pressing Menu.

Menu Nominal Frequency

The frequency deviation monitor FDM511 is suitable for 50Hz power networks and for
60Hz networks as well. Selection is made in this submenu.

After entering the menu with the Set button, the currently stored parameter is shown. To
change the nominal frequency, the Set button must be pushed once. The content of the
display starts flashing and can be altered by pressing Set again. When the designated
parameter appears, the configuration is stored and the submenu is left by pressing the
Menu button for at least one second. Menu must be pressed again to skip to the next
menu.

10

Menu Time Deviation Init

After power-up, the PL time is reset to the REF time and therefore the time deviation is
set to +00.000s. However, if a different start value is required because of any reason, a
time deviation preset value in the rage between -99.999s and +99.999s can be entered in
this menu. The PL time is calculated according to the new value of the time deviation.

After pressing the Set button once, the actual time deviation is displayed. The first digit
of the time deviation value starts flashing when the Set button is pressed once more. This
digit can be changed by using the Set button again. After the first digit has been changed
successfully, the Mode button is to press shortly to skip to the next digit that can be
changed in the same manner. After all digits are set and the designated value for the time
deviation is entered, the configuration is stored and the submenu is left by pressing the
Menu button for at least one second. FDM511 calculates the corresponding PL time, this
causes the "Fail"-LED to be switched on for a short time before normal operation is
started again. Menu must be pressed again to skip to the next menu.

Menu COM Parameter

The two setup menus PAR.COM0 and PAR.COM1 allow the configuration of the serial
RS232 ports COM0 and COM1.

Changing the COM Port parameters occurs by using the buttons Menu and Set, as
described already. The following settings are possible:

Baudrate: 0.6 / 1.2 / 2.4 / 4.8 / 9.6 and 19.2 kBaud

Framing: 7N2 / 7E1 / 7E2 / 8N1 / 8N2 / 8E1 / 7O2 and 8O1

Note: Make sure that the configuration of COM1 corresponds with the COM parameters
of the preconnected reference clock! This is mandatory, because the input of COM1 is
used to read in the REF time. The output sends a serial output string once per second, this
applies for COM1 as well as for COM0. The format can be selected in the next sub
menu.

11

Menu Output String

The two setup menus Str.COM0 and Str.COM1 allow the selection of the serial output
strings for COM0 and COM1.

Selection is done with the push buttons Menu and Set. The following strings are
available:

- Standard FDM String

- Short FDM String

- AREVA String

The format of the output strings is described in chapter "Serial Output Strings".

Menu Analog Outputs

FDM511 provides two independent analog outputs, A1 and A2. These outputs have a
voltage range of -2.5V to +2.5V, divided in 65536 steps. The value that causes a full
scale deflection of the corresponding analog output, can be defined in this menus (A1
Max. and A2 Max.). Either the frequency deviation or the time deviation can be selected
for monitoring via one of these analog outputs.

The following values can be defined for a full scale deflection:

Frequency Deviation:

- 500mHz (which corresponds with a frequency deviation of 0,2mHz/mV)

- 5Hz (which corresponds with a frequency deviation of 2mHz/mV)

Time Deviation:

- 10s (which corresponds with a time deviation of 4ms/mV)

- 100s (which corresponds with a time deviation of 40ms/mV)

If the full scale deflection of ±2,5V is reached while the corresponding value raises
forward, error bits are set (see "Error Bits") and the "Overflow"-LED is switched on.

The values of the two analog outputs can also be red out via the serial port COM0 by
sending the character 'A' (ASCII code 41h). FDM511 sends a string in the following
format:

A1:XXXX_A2:XXXX<CR><LF>

The values are given in hex code (0000h ... FFFFh). The initial state is 8000h.

12

Menu Error Bits

FDM511 recognizes fail and overflow events and sets or clears eight error bits
accordingly. These bits are shown in this menu. Reading this bits, the user is able to
understand why the "Fail"-LED or the "Overflow"-LED is switched on.

Each error bit represents a certain source of fault that occurs during the normal operation.
The format of the displayed bits is: X
following meaning:

X8: A2 Overflow, analog output 2 has reached its full scale deflection
X7: A1 Overflow, analog output 1 has reached its full scale deflection
X6: Time Deviation Overflow, the time deviation exceeds ±99.999s
X5: Frequency Overflow, the frequency deviation exceeds ±9.999Hz or

the frequency is < 45Hz or > 65Hz

X4: REF Free, no pulse per second (PPS) from the reference
X3: PL Free, no power line detected (PL time runs free)
X2: No Time String, no serial time string from the reference
X1: No PL Init, the PL time has not been initialized (yet)

X

X

X

X

X

X

8

7

6

5

4

X1. The single bits have the

3

2

The "Fail"-LED is on whenever one of the error bits X1 to X4 is set whereas the
"Overflow"-LED is switched on by one of the error bits X5 to X8 .

The error bits can be red out via the serial port COM0 by sending the character 'E'
(ASCII code 45h). The format of the return string is:

ERROR:X

X

X

X

X

X

X

8

7

6

5

4

X1<CR><LF>

3

2

Menu Serial Number

The serial number of the FDM511 is displayed in this menu. This number may be helpful
to know if the user asks Meinberg for support. The most significant eight digits of the
serial number are displayed first, after pressing the Set button the next digits are shown.

The serial number and the firmware revision of the FDM511 can be red out by sending
the three characters "SN!" via COM0 to the module that returns the following string:

SN: 041110000990 REV:01.00/01<CR><LF>

13

Serial Output Strings

Several output strings are available with the FDM511. Selection is made in the setup
menu "Str.COM0" and "Str.COM1". The format of the output strings as well as related
input strings or commands are described in the following.

Standard FDM String

The STANDARD string is a sequence of 62 ASCII characters containing the frequency
F, the frequency deviation FD, the REF time, the power line time PLT and the time
deviation TD, each item seperated by a space character. The string is send out at the
beginning of every new REF time second and ends with the characters Carriage-Return
(ASCII code 0Dh) and Line-Feed (ASCII code 0Ah). The letters displayed in italics are
replaced by the calculated values whereas the other characters are part of the string:

F:49.984_FD:-00.016_REF:15:03:30_PLT:15:03:30.378_TD:+00.378<CR><LF>

The meaning of the several values is described below:

F:49.984 The measured power line frequency with a resolution of 1mHz

FD:-00.016 The frequency deviation between calculated and nominal frequency,

with sign character (+/-), resolution: 1mHz, maximum: ±09.999Hz

REF:15:03:30 The reference time from the preconnected clock,

(hours:minutes:seconds)

PLT:15:03:30.378 The power line time, based on the mains frequency,

(hours:minutes:seconds.milliseconds)
Time jumps, like changeover in daylight saving or leap seconds,
will not be executed by the PL time!

TD:+00.378 The time deviation between REF time and PL time,

with sign character (+/-), resolution: 1ms, maximum: ±99.999s

14

Short FDM String

The SHORT string is a sequence of 23 ASCII characters containing simply information
about frequency deviation FD and time deviation TD, seperated by a space character.
The string is send out at the beginning of every new REF time second and ends with the
characters Carriage-Return (ASCII code 0Dh) and Line-Feed (ASCII code 0Ah). The
letters displayed in italics are replaced by the calculated values whereas the other
characters are part of the string:

FD:-00.016_TD:+00.378<CR><LF>

The meaning of the several values is described below:

FD:-00.016 The frequency deviation between calculated and nominal frequency,

with sign character (+/-), resolution: 1mHz, maximum: ±09.999Hz

TD:+00.378 The time deviation between REF time and PL time,

with sign character (+/-), resolution: 1ms, maximum: ±99.999s

Time Deviation Preset String

The time deviation TD can be preset to a value between -99.999s and +99.999s. This
can be done in the setup menu "Time Deviation Init" and also via the serial interface
COM0. Sending the following string to the FDM511 causes the module to set the time
deviation and the PL time is recalculated according to this new value:

TD:+05.873<CR><LF>

This serial method can be used to reset the time deviation back to +00.000s. This is also
caused by pulling down the /Reset input (see rear VG-Edge connector pin assignment)
or by a power-up reset.

Note: The described time deviation preset method is available via COM0, only, and not
with COM1! Furthermore, the output string STANDARD or SHORT has to be choosen
for COM0.

15

Areva FDM String

The AREVA string is a sequence of 71 ASCII characters containing the frequency F,
the frequency deviation FD, the time deviation TD, the power line time PLT and the
reference time REF (preceded by the 3 digit day-of-the year), each item seperated by the
characters Carriage-Return (ASCII code 0Dh) and Line-Feed (ASCII code 0Ah). Each
of the five data items is preceded by a fixed 3 digit address (020 ... 024). The string starts
with the STX character (start-of-text, ASCII code 02h) and ends with a terminating ETX
character (end-of-text, ASCII code 03h) on time with the change of the REF time
seconds. The letters displayed in italics are replaced by the calculated values whereas the
other characters are part of the string:

<STX> 02049.984<CR><LF>

021-0.016<CR><LF>
022+00.378<CR><LF>
02315_03_30.378<CR><LF>
024068_15_03_30_<CR><LF>

<ETX>

The meaning of the several values is described below:

49.984 The measured power line frequency with a resolution of 1mHz

-0.016 The frequency deviation between calculated and nominal frequency,

with sign character (+/-), resolution: 1mHz, maximum: ±09.999Hz

+00.378 The time deviation between REF time and PL time,

with sign character (+/-), resolution: 1ms, maximum: ±99.999s

15_03_30.378 The power line time, based on the mains frequency,

(hours_minutes_seconds.milliseconds)
Time jumps, like changeover in daylight saving or leap seconds,
will not be executed by the PL time!

068_15_03_30 The reference time from the preconnected clock,

(day-of-the-year_hours_minutes_seconds)

Over Range Condition

Whenever the frequency deviation or the time deviation exceeds its allowable limit
(±9.999Hz or ±99.999 seconds), an over range condition occurs. In this case the
corresponding value is sent out as a sign character (+ or -) followed by 9_ _ _ _ , where
the <_> character represents a space, e.g.: '+9 ' would follow +9.999 when
incremented by 0.001. Furthermore, this condition is indicated bythe Overflow LED.

16

Time Deviation Preset

A time deviation preset value in the range of -99.999 to +99.999 seconds can be set by a
serial ASCII command via the serial interface COM0. Sending the following string to the
FDM511 causes the module to set the time deviation and the PL time is recalculated
according to this new value. All previously accumulated time deviation is lost.

The ASCII command to set the preset value starts with the characters "F27PS" and
ends with the Carriage-Return (ASCII code 0Dh) and Line-Feed (ASCII code 0Ah).
The numbers displayed in italics are replaced by the time deviation preset value whereas
the other characters are part of the string. Examples:

send Preset Value +10.553:

F27PS+10.553<CR><LF> (string sent to FDM511)
OK<CR><LF> (response from FDM511)

send Preset Value -08.68:

F27PS-08.68<CR><LF> (string sent to FDM511)
OK<CR><LF> (response from FDM511)

read out the Preset Value:

F27PS<CR><LF> (string sent to FDM511)
F27PS=-08.680<CR><LF> (response from FDM511)

The preset value must be entered with the sign (+ or -), two digits as integer (01 to 99),
a dot as separatror (.) and two or three following decimal places. FDM511 returns the
OK acknowledge and recalculates the corresponding PL time. This causes the "Fail"­LED to be switched on for a short time before normal operation is started again.

Note: The described time deviation preset method is available via COM0, only, and not
with COM1! Furthermore, the output string AREVA has to be choosen for COM0.

17

Firmware Updates

Whenever the on-board software must be upgraded or modified, the new firmware can
be downloaded to the internal flash memory via the serial port COM0.

If the Menu button in the front panel is pushed down while the system is powered up,
a bootstrap-loader will be activated that waits for instructions from the serial port COM0.
The new firmware can be sent to the FDM511 from any standard PC with serial
interface. A loader program will be shipped together with the file containing the image of
the new firmware.

The contents of the program memory will not be modified until the loader program has
sent the command to erase the flash memory. So if the Menu button is pushed down
unintentionally while the system is powered up, the firmware will not be changed
accidentially. After the next power-up, the system will be ready to operate again.

CE Label

This device conforms to the directive 2004/108/EG on the
approximation of the laws of the Member States of the European
Community relating to electromagnetc compatibility.

18

19

Technical Specifications FDM511

DISPLAY: 8-digit alpha-numerical LED Display for showing the FDM511

results as well as status information. Character height: 5mm

INPUT SIGNALS: 10MHz oscillator clock (TTL level)

pulse per second, activ high (TTL level)
serial time string (RS232), Meinberg Standard Time String or
Uni-Erlangen Time String (see "Time Strings")
mains voltage, 70V... 270V, 45Hz ... 65Hz (protected with
200mA fuse, slow blowing)

OUTPUTS: 2 analog outputs: -2,5V ... 2,5V, resolution: 16 bit

fail output (TTL level)

overflow output (TTL level)
SERIAL
RS232 PORTS: 2 serial RS232 ports (COM0, COM1), configurable:

Baudrate: 600, 1200, 2400, 4800, 9600 or 19200 Baud

Framing: 7N2, 7E1, 7E2, 8N1, 8N2, 8E1, 7O2 or 8O1

output and average once per second

output string selectable (see chapter "Serial Output Strings")

ACCURACY OF
MEASUREMENT: frequency: accuracy of reference (10MHz) ±1mHz

time deviation:accuracy of reference (PPS) ±1ms

CONNECTORS: rear VG edge connector, mixed F/H, DIN 41612

Type F: 24 poles, type H: 7 poles

optional: mains socket in the front panel
POWER
REQUIREMENTS: +5V, 150mA

PHYSICAL
DIMENSIONS: Eurocard, 100mm x 160mm, 1.5mm Epoxy

FRONT PANEL: 3U / 12HP (128mm high x 61mm wide), Aluminium

AMBIENT
TEMPERATURE: 0 ... 50°C

HUMIDITY: max. 85 %

OPTIONS: power line input via mains socket in the front panel

RJ45 ethernet connection for monitoring the results via network

20

Time Strings

Format of the Meinberg Standard Time String

The Meinberg Standard Time String is a sequence of 32 ASCII characters starting with
the STX (start-of-text) character and ending with the ETX (end-of-text) character. The
format is:

<STX>D:dd.mm.yy;T:w;U:hh.mm.ss;uvxy<ETX>

The letters printed in italics are replaced by ASCII numbers whereas the other characters
are part of the time string. The groups of characters as defined below:

<STX> Start-Of-Text (ASCII code 02h)

dd.mm.yy the current date:

dd day of month (01..31)

mm month (01..12)

yy year of the century (00..99)

w the day of the week (1..7, 1 = Monday)

hh.mm.ss the current time:

hh hours (00..23)

mm minutes (00..59)

ss seconds (00..59, or 60 while leap second)

uv clock status characters (depending on clock type):

u: ‘#’ GPS: clock is running free (without exact synchr.)

PZF: time frame not synchronized
DCF77: clock has not synchronized after reset

‘ ‘ (space, 20h)

GPS: clock is synchronous (base accuracy is reached)
PZF: time frame is synchronized
DCF77: clock has synchronized after reset

v: ‘*’ GPS: receiver has not checked its position

PZF/DCF77: clock currently runs on XTAL

‘ ‘ (space, 20h)

GPS: receiver has determined its position
PZF/DCF77: clock is syncronized with transmitter

x time zone indicator:

‘U’ UTC Universal Time Coordinated, formerly GMT

‘ ‘ MEZ European Standard Time, daylight saving disabled

‘S’ MESZ European Summertime, daylight saving enabled

y anouncement of discontinuity of time, enabled during last hour

before discontinuity comes in effect:

‘!’ announcement of start or end of daylight saving time

‘A’ announcement of leap second insertion

‘ ‘ (space, 20h) nothing announced

<ETX> End-Of-Text (ASCII code 03h)

21

Format of the Uni Erlangen Time String

The time string Uni Erlangen (NTP) of a GPS clock is a sequence of 66 ASCII
characters starting with the STX (start-of-text) character and ending with the ETX (end­of-text) character. The format is:

<STX>tt.mm.jj; w; hh:mm:ss; voo:oo; acdfg i;bbb.bbbbn lll.lllle hhhhm<ETX>

The letters printed in italics are replaced by ASCII numbers whereas the other characters
are part of the time string. The groups of characters as defined below:

<STX> Start-Of-Text, ASCII Code 02h

sending with one bit occuracy at change of second

dd.mm.yy the current date:

dd day of month (01..31)

mm month (01..12)

yy year of the century (00..99)

w the day of the week (1..7, 1 = Monday)

hh.mm.ss the current time:

hh hours (00..23)

mm minutes (00..59)

ss seconds (00..59, or 60 while leap second)

v sign of the offset of local timezone related to UTC

oo:oo offset of local timezone related to UTC in hours and minutes

ac clock status characters:

a: ‘#’ clock has not synchronized after reset

‘ ‘ (space, 20h) clock has synchronized after reset

c: ‘*’ GPS receiver has not checked its position

‘ ‘ (space, 20h) GPS receiver has determined its position

d time zone indicator:

‘S’ MESZ European Summertime, daylight saving enabled

‘ ‘ MEZ European Standard Time, daylight saving disabled

f anouncement of discontinuity of time, enabled during last hour

before discontinuity comes in effect:

‘!’ announcement of start or end of daylight saving time

‘ ‘ (space, 20h) nothing announced

g anouncement of discontinuity of time, enabled during last hour

before discontinuity comes in effect:

‘A’ announcement of leap second insertion

‘ ‘ (space, 20h) nothing announced

22

i leap second insertion

‘L’ leap second is actually inserted

(active only in 60th sec.)

‘ ‘ (space, 20h) no leap second is inserted

bbb.bbbb latitude of receiver position in degrees

leading signs are replaced by a space character (20h)

n latitude, the following characters are possible:

‘N’ north of equator

‘S’ south d. equator

lll.llll longitude of receiver position in degrees

leading signs are replaced by a space character (20h)

e longitude, the following characters are possible:

‘E’ east of Greenwich

‘W’ west of Greenwich

hhhh altitude above sea level in meters

leading signs are replaced by a space character (20h)

<ETX> End-Of-Text, ASCII Code 03h

23

Rear Connector Pin Descriptions

Signal Name Pin Description

VCC in (+5V) B, D+Z2 +5V supply voltage

GND B, D+Z16 power supply ground

/BSL (/RESET) Z4 TD Reset (reset time deviation to +00.000s),

Boot signal for starting bootstrap loader (pull down

while powering-up)

P_SEC in D6 pulse per second input, TTL level, active high

10 MHz in Z12 10 MHz oscillator clock input, TTL-Pegel

COM0 TxD out D8 COM0 RS-232 transmit data output

COM0 RxD in B8 COM0 RS-232 receive data input

COM0 GND Z6 COM0 ground (=power supply ground)

COM1 TxD out D10 COM1 RS-232 transmit data output

COM1 RxD in B10 COM1 RS-232 receive data input

COM1 GND B12 COM1 ground (=power supply ground)

A1 out B4 analog output no. 1

A2 out B6 analog output no. 2

A_out GND D4 analog output ground (=power supply ground)

+USB D14 reserved for extensions

-USB B14 reserved for extensions

Fail out Z8 fail output (Fail LED), TTL level

Overflow out D12 overflow output (Overflow LED), TTL level

Reserve in Z10 input, reserved for extensions

L1 Z28 L, mains voltage

N D30 N, mains voltage

PE Z32 PE, protective earth conductor

24

Rear Connector Pin Descriptions

ZBD

2 VCC in (+5V) VCC in (+5V) VCC in (+5V)

4 /BSL A1 out GND

6 GND A2 out P_SEC in

8 Fail out RxD0 TxD0

10 Reserve in RxD1 TxD1

12 10MHz in GND Overflow out

14 -USB (optional) +USB (optional)

16 GND GND GND

20

22

24

26

28 L1

30 N

32 PE

25