Guralp Systems Limited
MAN-D24-0004 - Güralp DM24 MkⅢ Operator's Guide

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1. Preliminary Notes 2. Introduction 3. Installing the DM24 4. Using the DM24 5. Using Scream! 6. Command line interface 7. Inside the DM24 8. Güralp Compressed Format 9. Connector pin-outs 10. Digitiser specifications 11. Revision history

Section Index: 7.1. State of health information 7.2. Updating firmware using an EAM, Affinity or NAM 7.3. Updating firmware with Scream! 7.4. Setting up external triggering 7.5. Technical details

Chapter 7. Inside the DM24

7.1 State of health information

The DM24 outputs diagnostic information in a status stream. This is a special GCF stream whose name ends in 00.

Status streams can take two different forms, depending on the current transmission mode:

7.1.1 Heartbeat messages

These are output at regular intervals, and always have the same format. Older digitisers may not include all the lines described here.

64MB Flash File buffer : 65,520 Blocks Written 65,520 Unread 16 Free
Latest data [392] PLPGG SBHYX2 2006 1 18 14:55:57
Oldest data [400] PLPGG SBHYN4 2005 11 30 06:47:38
# 22 2006 1 18 14:48:36 No File Last Event
2006 1 18 14:56:15 1 MicroSeconds Fast Freq error 0 e-9 Auto 3D [-4]
PLPGG SBHY00 CMG-3T
Boot Log : 143 Power cycles 294 Watchdog resets
Last boot 2006 1 12 16:18:57 2006 1 17 17:15:14
2006 1 18 14:56:15 External supply : 13.0V Temperature 24.68'C
2006 1 18 14:56:15 Mass positions -486 -300 -424

7.1.1.1 Flash memory usage

The first three lines describe the internal Flash memory. First, the overall usage is described:

64MB Flash File buffer : 65,520 Blocks Written 65,520 Unread 16 Free

Here, a 64 Mb Flash memory store contains 65,520 data blocks, of which none have already been downloaded. This leaves 16 blocks of free space, since each block is exactly 1Kb long, and (65,520 + 16) × 1 Kb = 65,536 Kb = 64 Mb.

Latest data [392] PLPGG SBHYX2 2006 1 18 14:55:57
Oldest data [400] PLPGG SBHYN4 2005 11 30 06:47:38

These two lines show the date and time of the oldest and newest data in the buffer, together with the System ID (PLPGG) and the Stream IDs (SBHYX2 and SBHYN4) of the corresponding data stream.

7.1.1.2 Triggered events

# 15 Filed @ 64,167 PLPGG SBHYZG 2006 1 5 10:31:30 Last Event

This line gives the date and time of the last trigger, together with its System ID and Stream ID as above. Also given is the event sequence number (15, here) as used by the EVENTSLIST command, and the position in the buffer where data from the event begin.

If a trigger has occurred, but no data were output (e.g. because the digitiser was in DIRECT transmission mode), the digitiser will report

# 22 2006 1 18 14:48:36 No File Last Event

7.1.1.3 GPS

The next line describes the current status of the GPS system. When the digitiser is first powered up, the message will be something like

2005 8 10 12:35:00 GPS control OFF Auto 3-D [-5 Not sync'd]

The message GPS control OFF denotes that the clock is not yet being controlled by the GPS. Owing to noise purposely injected into the GPS timing stream, as well as issues of signal travel time, the GPS time cannot be directly used to synchronize the clock. Instead, the digitiser maintains a rolling average of time measurements, and uses this to apply corrections to the clock so that it remains accurate over a long period.

The Auto 3-D message denotes that the signal is strong enough to obtain a full 3-dimensional GPS fix. If the signal is weak, or there are too few satellites visible to the receiver, you may see Auto 2-D here. If the signal is too weak to obtain a fix, No FIX will be displayed.

After a short time, the message will change to

2005 8 10 12:36:00 GPS Control settling Auto 3-D [-5 Not sync'd]

Eventually, the GPS control system will be able to synchronize the internal clock, and the message will change to

2005 8 10 12:38:01 GPS Control settling Auto 3-D [-4]
2005 8 10 12:41:01 326 MicroSeconds Slow Freq error -7 e-9 Auto 3-D [-4]

The system is now reporting the current offset of the internal clock from GPS time (whether slow or fast), and the current frequency error. It will now continuously adjust the internal clock for as long as the GPS is powered up.

If you have chosen to save energy by enabling GPS power cycling, the DM24 will switch off the GPS once a satisfactory fix is obtained, and begin free-running on the internal clock. Whilst this is happening, the line will report

2005 8 10 17:06:27 GPS switched Off

7.1.1.4 Boot status

PLPGG SBHY00 CMG-3T
Boot Log : 143 Power cycles 294 Watchdog resets
Last boot 2006 1 12 16:18:57 2006 1 17 17:15:14

These three lines repeat information from the last re-boot:

7.1.1.5 Environmental measurements

2006 1 18 14:56:15 External supply : 13.0V Temperature 24.68'C

The next line displays the current state of the DM24's power supply, and its internal temperature.

7.1.1.6 Mass positions

2006 1 18 14:56:15 Mass positions -486 -300 -424

The final line provides the instantaneous mass positions reported by the sensor at the time given.

7.1.2 Status blocks in continuous mode

In continuous mode, each status block contains a number of single-line messages:

2006 1 18 14:40:00 o/s= 90 drift= 0 pwm= 8187 Auto 3D
2006 1 18 14:41:00 o/s= 90 drift= 0 pwm= 8187 Auto 3D
2006 1 18 14:42:00 o/s= 90 drift= 0 pwm= 8187 Auto 3D
2006 1 18 14:43:00 o/s= 78 drift= -12 pwm= 8188 Auto 2D
2006 1 18 14:44:00 o/s= 89 drift= 11 pwm= 8188 Auto 3D
2006 1 18 14:45:00 o/s= 94 drift= 5 pwm= 8188 Auto 3D
2006 1 18 14:45:00 External supply : 13.0V Temperature 24.62'C
2006 1 18 14:46:00 o/s= 148 drift= 54 pwm= 8188 Auto 3D
2006 1 18 14:47:00 o/s= 174 drift= 26 pwm= 8188 Auto 3D
2006 1 18 14:48:00 o/s= 211 drift= 37 pwm= 8188 Auto 3D
2006 1 18 14:48:36 SOFTWARE Trigger : Trigger# 22
2006 1 18 14:49:00 o/s= 263 drift= 52 pwm= 8187 Auto 3D
2006 1 18 14:49:10 End of Trigger

The messages appear in the order they are generated by the different software modules inside the digitiser.

7.1.2.1 GPS status messages

The status of the attached GPS receiver is reported every minute:

2006 1 18 14:47:00 o/s= 174 drift= 26 pwm= 8188 Auto 3-D

In this line:

Every 20 minutes, at 10, 30 and 50 minutes past the hour, the GPS synchronization status is displayed. This line has the same format as the GPS line in the heartbeat message, e.g.

2005 8 10 12:41:01 326 MicroSeconds Slow Freq error -7 e-9 Auto 3-D [-4]

Finally, every hour, the DM24 displays general timing and position information, including details of the visibility of GPS satellites:

2005 6 8 11:00:00 GPS Date/Time 08/06/05 11:00:00
2005 6 8 11:00:00 Auto 3-D SV#'s 4 7 13 20 23 24 25 ( 7 )
2005 6 8 11:00:00 Lat 51'21.6591N Long 001'09.8218W

SV# stands, officially, for Space Vehicle number. Each GPS satellite has it's own unique identification number, or SV#, and the list shows which are currently usable (satellite numbers 4, 7, 13, 20, 23, 24 and 25 in this example). A minimum of four is required to obtain a full 3-dimensional GPS fix.

7.1.2.2 Trigger notifications

When a trigger occurs, a message is immediately saved to the current status block. You may not see this message straight away, however, since the status block must be full before the digitiser will send it.

2006 1 18 14:48:36 SOFTWARE Trigger : Trigger# 22

The trigger type is mentioned, as well as the sequence number (for later retrieval, if necessary, using the EVENTSLIST command). When the trigger condition ends, the system reports

2006 1 18 14:49:10 End of Trigger

7.1.2.3 Environmental measurements

These are measured every 10 minutes (at 5, 15, 25, 35, 45 and 55 minutes past the hour), and are given in the same form as for heartbeat messages:

2006 1 18 14:45:00 External supply : 13.0V Temperature 24.62'C

7.2 Updating firmware using an EAM, Affinity or NAM

The easiest way to update the digitiser firmware is by connecting it to a Platinum device, such as an EAM, Affinity or NAM. If the digitiser is part of a DM24-SxEAM or integrated *TDE instrument, this connection is already made.

The DM24 firmware can be upgraded through the web interface, using a check-box at the bottom of the data acquisition configuration page, or from the command line, with the dm24-upgrade command. Please see the platinum manual, MAN‑EAM‑0003 for more details.

7.3 Updating firmware with Scream!

You can update the digitiser firmware using any terminal program which supports the Xmodem protocol, such as minicom, hypertrm or Scream!. If you are using Scream!, right-click on the digitiser’s icon () in the main window and select Terminal from the pop-up menu:

Scream-terminal-window

If you are using a different emulator, open a window as normal with appropriate Baud rate. The communications settings should be 8-N-1 with no flow control.

Check that there is two-way communication with the digitiser by pressing Enter. The digitiser should reply with ok on a new line.

Type re-boot to reinitialize the digitiser, and confirm with y. As it is restarting, the digitiser will report its status over the terminal connection, followed by a maintenance menu:

MPE ARM ANS ROM PowerForth v6.30

ARM Serial BootStrap v1.100, 11 August 2003

Copyright (c) 2002-3 GSL, EDSL & MicroProcessor Engineering Ltd.

Port 0 38400 baud Port 1 4800 baud Port 2 38400 baud

Guralp Systems Ltd - ARM-BOOT v3.0 mgs 13/12/12 (Build _02)

System Code versions loaded :-

Current 0105:0000 Guralp Systems Ltd - DM+FW v.107 mgs 13/09/16 (Build _26)

Backup 010E:0000 Guralp Systems Ltd - DM+FW v.107 mgs 13/09/16 (Build _26)

Previous 0117:0000 Guralp Systems Ltd - DM+FW v.106 mgs 11/11/14 (Build 57w)

DSP Code :

0103:0000 dsp1091.bin loaded 2016-09-29 Default

0104:0000 dsp1091.bin loaded 2016-09-29

Command keys:

C - set real time Clock (2016 9 29 14:37:06 )

I - view/upload InfoBlock

F - run the Forth monitor

S - update System program

O - select Other system program

B - update Boot program

D - update DSP code

T - Toggle default DSP code

Q - Quit maintenance system

5 seconds to auto-start:

If you do not press a key in the next three seconds, the DM24 will start up normally.

The DM24 has three firmware components, which can be updated separately: the system program, the DSP code and the boot loader. Firmware releases are available on the Güralp Systems website. If a release updates more than one component, you should be sure to update the boot loader first, then the system program and DSP code.

7.3.1 Loading a new boot loader

Press at the maintenance menu to update the boot-loader.

The digitiser will then request a transfer using the Xmodem protocol. If you are using Scream!, a file browser window will appear automatically.

Note: Be sure to check beforehand that the file is a valid DM24 boot loader! Replacing the boot loader with invalid code will make it impossible to boot up the digitiser. If in any doubt, please contact Güralp Systems technical support for advice before proceeding.

Navigate through the directories on your computer and select the file to be uploaded, or type in its full path and file name. Click Open.

DM24-select-file-to-transmit

Whilst the file is loading, a progress window will be displayed.

Once the file is fully transferred, the DM24 will need to reboot. It will ask you for confirmation: Press ENTER, and wait whilst the system boots.

When you are returned to the maintenance menu, you can proceed to install other firmware modules or key ENTER, which will cause the system to continue to boot.

7.3.2 Loading a new system program

To update the system firmware, press at the maintenance menu. The digitiser will display

Update System program

The digitiser will then request a transfer using the Xmodem protocol, as described above.

Whilst the file is loading, a progress window will be displayed. Depending on the speed of the link, it may take up to 20 minutes to transfer the firmware.

Once the file is fully transferred, the DM24 will return to the maintenance menu. Press ENTER, and wait whilst the system boots.

7.3.3 Loading new DSP code

Press at the maintenance menu. The digitiser will reply with

Enter 0/1 to select DSP code to update

Select which of the two DSP code slots you want to overwrite, and press ENTER. The default is always 0.

Enter Filename/date – upto 31 characters

You can enter a descriptive string for the DSP code here. The DM24 will print this string at every boot-up, to remind you which version of the DSP code you are using.

Note: The EAM and other automated systems populate this with a string like:

dsp1091.bin loaded 2016-09-23

When you press ENTER, the digitiser will then request a transfer using the Xmodem protocol, as described above.

7.4 Setting up external triggering

Güralp digitisers and digital instruments can be supplied with external triggering capabilities installed. The external trigger system is designed for maximum flexibility: you can trigger other digitisers or your own equipment using built-in relays, or any equipment may be used as a trigger source. In addition, a trigger circuit can link together any number of digitisers so that they trigger simultaneously when they receive a signal.

7.4.1 Overview

The digitiser or digital instrument has two internal components related to triggering.

The Trigger Out pins are not connected if you provide a Trigger In voltage. The instrument must trigger itself for the relay to switch. This arrangement prevents any trigger loops from occurring.

The diagrams on this page show the additional connections you will need to make. Pins A and B, and the data pins, should be connected to your power and data systems as normal.

7.4.2 Triggering your own equipment

If your equipment can trigger from 24 V DC, the simplest arrangement is to use the voltage across the sensor's power supply as a trigger.

If your equipment needs a different voltage, you will need to provide a separate voltage source for the triggering system. Be careful not to connect two power supplies together. The instrument's power supply can be protected by inserting a diode from pin B to pin E (see below).

7.4.3 Using an external trigger source

To trigger an instrument from an external source through a relay:

If you prefer, you can use a separate power source for your trigger generator. However, because pin H is referenced to power ground, the external power supply must share a common ground with that of the digitiser, so you should connect the power supply ground to pin A.

7.4.4 Triggering several Güralp instruments simultaneously

A common use of the external triggering feature is to ensure that all instruments in an array trigger at the same time. This can be achieved with the wiring layout below. With this arrangement, any instrument can generate a trigger, which will be passed on to all the instruments in the array.

For each instrument:

The diode at pin E is important, because if two instruments generate a trigger simultaneously, their power supplies will both be connected via the internal relay contacts to the common trigger line on pins H, and hence connected together. This can cause considerable current flow with consequent risk of fire, as well as severe damage to equipment and cables.

In the case where a single power supply is used to power all of the equipment, this is not an issue and pin E should be connected directly to pin B on all units. Pin B should then also be connected to the power supply's positive terminal.

The more common case, where each unit has it's own power supply, is shown below. Power supply wiring is omitted for the sake of clarity but note that all the power supply's ground terminals will be connected together via the links between pin A on each unit. The power supplies must, therefore, have floating outputs or grounded negative terminals.

7.5 Technical details

Internally, DM24 digitisers are structured as shown in the following diagram, where each box represents a separate internal subsystem.

The system is designed around a low power, high performance ARM microprocessor. This is a 32-bit processor with a large address space for data storage and manipulation. It also includes many integrated functions such as multiple timers and serial I/O ports. In addition, the system contains a Cirrus Logic CS5376 digital filtering chip-set and TMS320VC33 digital signal processor (DSP). The CS5376 provides data to the DSP at 2,000 samples per second, triggered by timing signals from the ARM processor. The DSP can control all 5 ADCs and process the data in real time.

An important feature of the system design is its ability to synchronise the sampling of the analogue to digital converter to an external time reference. This way, data samples are accurately time stamped at source. To keep sampling accurately in step with UTC, the microprocessor's time-base is synchronized to an external reference, derived from GPS or, in larger arrays, to a centrally-transmitted time reference. Sharing a time reference avoids the cost and power consumption of multiple GPS receivers and, since it only involves sending 2 characters per second, it can utilise a low bandwidth link.

To achieve the high degree of timing precision required for a 24-bit digitiser system, the microprocessor time-base is run from a precision voltage controlled oscillator. On-board software keeps this oscillator tuned to the external reference so that its frequency is accurately set and maintained through changes in temperature or ageing. Once the system has stabilised, the control is sufficiently accurate to maintain precision sampling for several days without an external reference. The system also automatically compensates for the pure time delay introduced by the digital filtering/decimation processes in the DSP.

The DSP software consists of 6 cascaded programmable filter/decimation stages, which allow you to select multiple data output rates simultaneously. Each stage can be set individually for decimation factors of 2, 4, or 5. Data can be output at up to four different rates. For example, a system can be configured to provide data at 200, 50, and 10 samples per second, covering the whole of the seismological broad band range. The configuration of the DSP is programmable in the field via the host ARM microprocessor.

The DM24's interface to the world is via its serial ports. Port 0 is used for GCF data output. Port 1 is the NMEA input from the GPS receiver and Port 2 is the system's console. The console can be used as a command line interface without interrupting data flow via Port 0.

PreviousNext

1. Preliminary Notes 2. Introduction 3. Installing the DM24 4. Using the DM24 5. Using Scream! 6. Command line interface 7. Inside the DM24 8. Güralp Compressed Format 9. Connector pin-outs 10. Digitiser specifications 11. Revision history