Phoenix Geophysics MTU-TXC User manual

MTU-TXC
Current Source
Controller
User Guide
Version 1 February 2004
PHOENIX GEOPHYSICS

MTU-TXC
Current Source
Controller
User GuideVersionj/February 2004

Printed in Canada on water resistant Xerox® Laser Never-Tear
paper.
This User Guide was created in Adobe FrameMaker 7.0, using
Verdana, Tahoma, and Lucida Bright fonts.
Writing and Production: Stuart Rogers.
Copyright 2004 Phoenix Geophysics Limited.
All rights reserved. No part of this Guide may be reproduced or
transmitted in any form or by any means electronic or mechanical,
including photocopying, recording, or information storage and
retrieval system, without permission in writing from the publisher.
Address requests for permission to:
Phoenix Geophysics Limited, 3781 Victoria Park Avenue, Unit 3,
Toronto, ON Canada M1W 3K5, or [e-mail].
Information in this document is subject to change without notice.
MTU-TXC and the Phoenix logo are trademarks of Phoenix
Geophysics Limited. CompactFLash is a trademark of SanDisk
Corporation.

i i
Contents
Controlling a current source with the MTU-TXC. . . . . . . 1
Introduction to the MTU-TXC . . . . . . . . . . . . 2
Available frequencies . . . . . . . . . . . . . . . . . . . . . . . . . 2
About phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
About the schedules . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Table 1-1: Transmission Codes and Resulting Waveforms 4
PC requirements . . . . . . . . . . . . . . . . . . . . . . . . 7
Configuring the parallel port . . . . . . . . . . . . . . . . . . . . 7
Troubleshooting parallel port communications . . . . . . . 10
General techniques. . . . . . . . . . . . . . . . . . . . . 11
Handling locking-ring connectors . . . . . . . . . . . . . . . . 11
Connecting a PC. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Connecting the GPS antenna . . . . . . . . . . . . . . . . . . . 13
Grounding the MTU-TXC . . . . . . . . . . . . . . . . . . . . . . 14
Protecting the CompactFlash card slot . . . . . . . . . . . . .14
Connecting the battery . . . . . . . . . . . . . . . . . . . . . . . .15
Connecting to a current source or receiver . . . . . . . . . .17
Understanding LED indications . . . . . . . . . . . . . . . . . .18
System startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Initial satellite lock . . . . . . . . . . . . . . . . . . . . . . . . . 18
Using schedule files . . . . . . . . . . . . . . . . . . . . .19
Creating a frequency schedule file . . . . . . . . . . . . . . . .19
Converting the schedule to binary format . . . . . . . . . . .22
Examining a binary schedule file . . . . . . . . . . . . . . . . .22
Transferring the schedules to the MTU-TXC . . . . . . . . . .23
Activating a schedule . . . . . . . . . . . . . . . . . . . . . . . . .24
Saving settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Shutting down the MTU-TXC . . . . . . . . . . . . .25
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

ii ii

1 Chapter 1 1
Chapter
Controlling a current source with
the MTU-TXC
The MTU-TXC Current Source Controller output is
adjustable for both frequency domain (FD) and time
domain (TD) techniques.
This chapter tells you how to:
• make connections to the MTU-TXC and current
sources, receivers, and a PC.
• create, convert, and transfer schedule files.
• operate the MTU-TXC with a geophysical current
source.

2 Chapter 1 Introduction to the MTU-TXC 2
Introduction to the MTU-TXC
The MTU-TXC is a GPS-satellite-synchronized clock
used to control geophysical current sources and
provide timing signals to receivers. The MTU-TXC takes
as input a schedule of frequencies in the time domain
or frequency domain, and controls the connected
current source or receiver according to that schedule.
Various schedules can be saved in files on the unit’s
data directory. The operator chooses which schedule to
use by connecting a PC and changing a single
parameter using a small utility program.
Available frequencies
The MTU-TXC derives its frequencies from a 921.6kHz
signal, and therefore it may not be able to produce
exactly the requested frequency. Use at least 6
(preferably 8) significant digits when specifying a
frequency. The MTU-TXC will produce the closest
approximation possible.
About phase
For synchronization with other Phoenix GPS-equipped
instruments, the output phase is such that if the
waveform were extended backward in time, the centre
of the positive on time (or the negative on time in
unipolar negative) would align with 2000/01/01
00:00:00 UTC. (UTC leap seconds are ignored for this
purpose.)
Note Leap seconds may occur at the beginning of January
or July every few years, as determined by the
International Earth Rotation and Reference Systems
Service (IERS). If a leap second happens to occur
while the MTU-TXC is generating a waveform, there
may be a discrepancy of 1s in its phase. To prevent
problems, consult the IERS Web site
(http://www.iers.org/) for notifications and avoid
transmitting during the occurrence of a leap second.
About the schedules
The MTU-TXC calculates each schedule to begin at
00:00:00 UTC each day and repeat continuously. For

3 Chapter 1 Introduction to the MTU-TXC 3
this reason, it is best to plan your schedules so that an
integral number of repetitions can occur in a 24-hour
period. If the total duration of your schedule does not
divide evenly into 24h and you happen to be
transmitting at 00:00:00 UTC, you will experience an
abrupt return to the first frequency in the schedule.
Each schedule file can contain up to 100 entries
specifying the waveform, the frequency, and the
schedule. You can create these files in any spreadsheet
or text-processing program that can produce Comma
Separated Values (.csv) or V6-A ASCII text format
(.fst) files. (The Generate Frequency Stepping Table
utility program translates the .csv or .fst files into
binary files before transfer to the MTU-TXC.)
Table 1-1 on page 4 illustrates the waveform that will
be generated for each Time and Frequency domain
code setting in the schedule files.

4 Chapter 1 Introduction to the MTU-TXC 4
Table 1-1: Transmission Codes and Resulting Waveforms
Domain Ratio
ON:OFF
Duty
Cycle Waveform Code
Time 1:1 50%
bipolar
TD50
Time 1:2 33.33%
bipolar
TD33
Time 1:3 25%
bipolar
TD25
= Aligned with 2000/01/01 00:00:00 UTC.
1 : 1 : 1 : 1
1 : 2 :1 : 2
1 : 3 : 1 : 3

5 Chapter 1 Introduction to the MTU-TXC 5
Frequency — 100%
bipolar
FD
Frequency 10:8 55.55%
bipolar
FD9
Time 1:1 50%
unipolar
positive
TD50P
Time 1:2 33.33%
unipolar
positive
TP33P
Table 1-1: Transmission Codes and Resulting Waveforms (continued)
Domain Ratio
ON:OFF
Duty
Cycle Waveform Code
= Aligned with 2000/01/01 00:00:00 UTC.
1 : 1
f9f+
(
)
:11
1:1
1 : 1 : 1 : 1
1 : 2 :1 : 2

6 Chapter 1 Introduction to the MTU-TXC 6
Time 1:3 25%
unipolar
positive
TD25P
Time 1:1 50%
unipolar
negative
TD50N
Time 1:2 33.33%
unipolar
negative
TD33N
Time 1:3 25%
unipolar
negative
TD25N
Table 1-1: Transmission Codes and Resulting Waveforms (continued)
Domain Ratio
ON:OFF
Duty
Cycle Waveform Code
= Aligned with 2000/01/01 00:00:00 UTC.
1 : 3 : 1 : 3
1 : 1 : 1 : 1
1 : 2 :1 : 2
1 : 3 : 1 : 3

7 Chapter 1 PC requirements 7
PC requirements
The PC requires a properly configured ECP parallel port.
The PC does not have to be connected to the MTU-TXC
until you are ready to download or activate a schedule.
The software required is a text editor such as Notepad
or a spreadsheet program such as Microsoft™ Excel,
the Phoenix Generate Frequency Stepping Table utility,
the Phoenix WinHost program, and the Phoenix Raw
Parameter Table Interface.
To install the Phoenix PC software:
1. Insert either the CD-ROM or floppy disk into the PC
drive.
2. Run the Setup.exe program contained on the disk
and follow the on-screen instructions.
Configuring the parallel port
The Phoenix Raw Parameter Table Interface program
communicates with the MTU-TXC via a special cable
(part number 6218) and adapter (part number 6228)
connected to the PC’s parallel port.
The parallel port must be configured as an Extended
Capability Port (ECP). ECP provides a high-performance
bi-directional communication path between the PC and
the instrument. Your PC may already be configured to
use the ECP protocol, in which case you only need to
verify the setup if you experience problems using the
software. Otherwise, you will have to configure the port
in your computer’s CMOS Setup.
To determine the parallel port configuration:
1. Right-click on My Computer and choose Properties.
2. Click the Device Manager tab. (In Windows XP, click
the Hardware tab, then click the Device Manager
button.)
3. Expand the Ports (COM & LPT) entry by clicking the
plus sign to the left of it.

8 Chapter 1 PC requirements 8
4. If there is an ECP Printer Port listed, verify the ECP
port Properties as described on page 10. If there is
no ECP Printer Port listed, follow the next procedure
to create the port.
To create an ECP parallel port:
1. Be prepared to issue the keyboard command that
puts your PC into CMOS Setup during system
startup (“cold boot”). This command varies from
one manufacturer and model to another. Consult
your PC documentation or the manufacturer’s Web
site. (Typically, the command key is one of the
Function keys or the Insert or Delete key. Many
computers, when they are powered on, will display
a prompt that names the command key.)
2. Follow the instructions just given to determine the
parallel port configuration. If there is an SPP
Standard Parallel Port listed, select it and click
Remove. Close the Properties dialog box.
3. Restart your computer. (You may have to shut down
your computer completely before restarting it in
order to reach the CMOS Setup prompt.)
4. During the restart, before the Windows logo screen
appears, type the keyboard command to enter
CMOS Setup.
5. Consult your PC documentation or follow the on-
screen prompts for instructions, and change the

9 Chapter 1 PC requirements 9
parallel port to ECP. If there are options for a DMA
channel or Interrupt Request, accept the defaults.
6. Save the new settings and exit CMOS Setup.
7. Allow Windows to continue loading, and observe
whether it detects and configures the new ECP port.
If it does, verify the ECP port Properties as
described on page 10.
8. If Windows does not detect and configure the ECP
port, follow the next procedure to add it manually.
If you are not sure whether Windows detected the port,
repeat the procedure on page 7 to determine the
parallel port configuration.
To add an ECP port manually:
1. Create the ECP port in CMOS Setup as just
described.
2. When Windows finishes loading, click on Start,
point to Settings, then click Control Panel.
3. Click on Add New Hardware.
4. Follow the on-screen instructions. When asked “Do
you want Windows to search for your new
hardware?” click “No, I want to select the hardware
from a list.”
5. Choose Ports (COM & LPT) from the list and then
click on (Standard port types) and ECP Printer Port.
6. Follow the on-screen instructions to finish adding
the port, then follow the next procedure to verify
the port properties.

10 Chapter 1 PC requirements 10
To verify the ECP port properties:
1. Right-click on My Computer and choose Properties.
2. Click the Device Manager tab.
3. Expand the Ports (COM & LPT) entry by clicking the
plus sign to the left of it.
4. Select the ECP Printer Port and click Properties.
5. If your operating system is Windows XP, click the
Port Settings tab. Select “Use any interrupt
assigned to the port.”
6. Click the Resources tab.
7. Examine the Resource type list. It should contain
three or four lines: two Input/Output Ranges, an
Interrupt Request, and possibly a Direct Memory
Access setting:
If any line other than Direct Memory Access is
missing, you may have to restart your computer to
see the new properties. If the new properties do not
appear even after a restart, you may have to
upgrade the BIOS of the PC in order to use the
Phoenix software.
8. Examine the Conflicting device list. If there are any
conflicts, resolve them according to the instructions
in your PC documentation or in the Windows Help
files.
Troubleshooting parallel port
communications
If you experience communication problems between
the PC and the MTU-TXC, there may be a problem with
the parallel port configuration or operation. Try these
suggestions:
• Verify that the cable and adapter are correct and
that both are being used. A laplink cable alone
without the adapter will not work.
• Verify that the cable and adapter are working
properly. Try using them with a different
instrument, or try substituting a cable and adapter
that you know are working properly.

11 Chapter 1 General techniques 11
• Verify the ECP port properties as described on
page 10.
• Verify that the parallel port is working properly by
connecting a printer (using a standard printer
cable) and printing a test document.
If your operating system is Windows XP and you
receive Error code 54, “ECP driver is not set up to use
an interrupt,” verify that the Port Settings will “Use any
interrupt assigned to the port.” (See step 5 on
page 10.)
General techniques
This section explains how to connect the GPS antenna,
the battery, and a PC to the MTU-TXC.
Handling locking-ring connectors
The PC and current source or receiver connections are
made with military-grade cylindrical bayonet-lock
connectors equipped with protective caps or locking
rings. Most of these caps can be joined together in
pairs to keep them clean while the equipment is in use.
Fig. 1-1: Military-grade cylindrical connector and cap.
The GPS antenna and battery connections are made
with similar but smaller locking connectors; the
instrument terminals have caps, but the cable ends do
not.
Fig. 1-2: GPS and Battery connectors.

12 Chapter 1 General techniques 12
To remove a protective cap:
• On the MTU-TXC, push on the cap and turn it
counterclockwise.
• On a cable end, hold the cap in one hand and with
the other hand, push the locking ring toward the
cap and turn the ring counterclockwise.
To make cable connections:
• Fit the cable end to the receiving connector and
turn the locking ring clockwise until it locks in place.
To disconnect a cable:
• Push the locking ring toward the connection and
turn the ring counterclockwise.
To keep connectors clean:
1. When a connection is made, always join the two
loose protective caps and lock them to each other.
2. When disconnecting equipment, always replace the
protective caps immediately and lock them in place.
Connecting a PC
A special cable is supplied to connect the PC parallel
port to the MTU-TXC.
Fig. 1-3: MTU⁄MTU-A to PC parallel port cable.
To connect a PC:
1. Fit the PC cable to the parallel port on your
computer.
2. Fit the other end of the cable to the PARALLEL I/O
connector of the MTU-TXC as described on page 11.

13 Chapter 1 General techniques 13
Tip To prevent damage to the PC because of accidental
polarity reversal, start up the PC and the MTU-TXC
independently and verify their proper operation before
connecting the two together.
Connecting the GPS antenna
The global positioning system (GPS) antenna must
always be connected to the MTU-TXC when operating
the equipment, because the satellites provide the
necessary time signals. The cable has two connectors:
one with slots for quick connection to the MTU-TXC,
and one with threads for connection to the antenna.
To connect the GPS antenna:
1. Screw the threaded connector of the antenna cable
to the underside of the antenna head. (See
Fig. 1-4.)
2. Fit the slotted connector to the GPS ANT connector on
the MTU-TXC as described on page 11.
3. Open the antenna tripod and position the GPS
antenna so that it is level, stable, and has
unobstructed sight lines to as much of the sky as
possible. If necessary, tape the antenna tripod to
another object (e.g., a stake, post, or larger tripod)
so that it is raised above tall grass or shrubs.
Fig. 1-4: GPS antenna cable connectors.
to GPS
antenna
to MTU-TXC

14 Chapter 1 General techniques 14
Tip In many cases, the antenna tripod can be left
unopened, propped up in the side pocket of the
MTU-TXC canvas case. The antenna can receive satellite
signals even if the MTU-TXC is wrapped in a protective
tarpauline. (Just make sure the top of the antenna
remains level.)
If you must stretch the cable in order to position the
antenna, prevent damage to the connectors by
providing strain relief at each cable end. Tape the cable
to the tripod and the instrument handle so that there is
some slack at each connector.
Grounding the MTU-TXC
Warning To prevent damage to the instrument, always
connect a ground electrode to the GND terminal
first, before making any other connections.
To ground the MTU-TXC:
1. If necessary, remove 2–2.5cm of insulation from
the end of a grounding wire, and twist the strands
tightly together.
2. Unscrew the GND terminal on the MTU-TXC until it
stops.
3. Thread the twisted strands of the cable through the
hole in the shaft of the terminal, and wrap the free
end clockwise around the shaft. If your cable is very
thick, you may have to cut some of the strands at
the insulation in order to fit the wire through the
hole in the shaft.
4. Tighten the terminal securely.
5. Connect the other end of the cable to a suitable
ground.
Protecting the CompactFlash card
slot
The MTU-TXC has a slot to accept a CompactFlash (CF)
card. The CF card fits into a slot in the front of the
MTU-TXC, protected by a small watertight cover.
The card slot is intended for future use; no card is
shipped or used in operating the unit. However, it is
!