Thurlby Thandar Instruments TGR1040 User manual

THURLBY THANDAR INSTRUMENTS
1 GHz SYNTHESISED RF SIGNAL GENERATOR
TGR1040
INSTRUCTION MANUAL

Introduction
This low cost, synthesised RF signal generator features a wide amplitude range, low noise and
inherently good frequency stability. The generator also features internal and external FM. The
instrument can be operated manually via the front panel or remotely controlled via the RS232
(standard) or GPIB (optional) interfaces. It is suitable for FM radio receiver sensitivity
measurements, system gain measurements, oscillator substitutions, EMC/antenna/field strength
measurements and as a signal source for many other RF circuit and system development tasks.
In addition, the generator's low cost, ease of use and remote control make it eminently suitable
for most production and development applications where a basic, stable signal source is required.
Table of Contents
Specifications 2
EMC 5
Safety 6
Installation 7
Connections 8
Front Panel Connections 8
Rear Panel Connections 8
Operation 9
General 9
Step Size 10
Setting Frequency 10
Setting Level 10
Modulation 11
Storing and Recalling Set-ups 11
Remote Operation 12
Address and Baud Rate Selection 12
Remote/Local Operation 12
RS232 Interface 12
Remote Commands 19
Maintenance 22
Appendix 1. Error Messages 23
Appendix 2. Factory Defaults 24
Instructions en Francais 25
Bedienungsanleitung auf Deutsch 46
Istruzioni in Italiano 66
Instrucciones en Español 86
1

Specifications
Specifications apply after 30 minute warm-up in an ambient of 5°C to 40°C
FREQUENCY
Frequency Range: 10 MHz to 1000 MHz
Setting Resolution: 1 kHz by direct keyboard entry, or in user-set increments of 1kHz to
999.999 MHz by rotary control or increment–decrement keys.
Display Resolution: 1 kHz
Accuracy: ± 2 ppm over the temperature range 5°C to 40°C.
Stability: <1ppm/year ageing.
Phase Noise: <−110dBc/Hz at 25 kHz offset, 500 MHz carrier.
Residual FM:
(FM Off)
Equivalent peak deviation in a 300 Hz to 3.4 kHz bandwidth:
12 Hz at 100 MHz carrier
25Hz at 500 MHz carrier
60 Hz at 1000 MHz carrier
OUTPUT LEVEL
Output Level Range: –127dBm to +7dBm (0.1µV to 500 mV into 50Ω).
Setting Resolution: 0.1dB (or 0.01µV to 1mV) by direct keyboard entry, or in user-set increments of
0.1dB to 100dB (or 0.01µV to 100mV) by rotary control or increment–decrement
keys.
Accuracy: Better than ± 2dBm, except for output levels <–70dBm at 500 -1000 MHz,
± 3dBm.
Harmonics: Typically <–25dBc, maximum –20dBc, any carrier frequency, output level ≤0dBm.
Non-Harmonic Spurii: ≤– 60dBc at ≥8kHz offset.
Carrier Leakage: ≤0.5µV generated in a 50Ωload by a 2 turn 25mm diameter loop, 25mm from
the generator, with the output set to ≤–10dBm into a 50Ωsealed load.
Output Impedance: 50Ω
Output Connector: TYPE N
Output Switch: RF OUT on-off switch with LED showing ON status.
FM MODULATION
Peak Deviation: 0.5 kHz to 100 kHz.
Setting Resolution: 0.5 kHz by direct keyboard entry, rotary control or increment–decrement keys.
Modulation Frequency: Internal 1kHz; External 300 Hz to 50 kHz
Deviation Accuracy: <±15% of setting ± 0.5kHz, excluding residual FM, for 1 kHz modulation, internal
or 1Vrms external.
External Modulation
Frequency Response: ± 1dB from 300 Hz to 50 kHz relative to 1 kHz.
Distortion: <2% total harmonic distortion at 1 kHz modulating frequency, 100 kHz deviation
and 500 MHz carrier.
Input Impedance: 100kΩ
Input Connector: BNC
2

INTERFACES
Full remote control facilities are available through the RS232 (standard) or optional GPIB interfaces.
RS232: Variable Baud rate, 19200 Baud maximum, 9-pin D-connector. Fully compatible
with Thurlby Thandar ARC (Addressable RS232 Chain) system.
IEEE-488: Conforming with IEEE488.1 and IEEE488.2.
GENERAL
Display: 20 character x 4 row backlit alphanumeric LCD
Data Entry: Keyboard selection of frequency, amplitude, etc.; value entry direct by numeric
keys or by rotary control.
Stored Settings: Up to 9 complete instrument set-ups may be stored and recalled from battery-
backed memory. Typical battery life is 5 years.
Size: 3U (130mm) height; half-rack (212mm) width; 330mm long.
Weight: 4.6 kg. (10 lb)
Power: 100V, 110V-120V or 220V-240V AC ±10%, 50/60Hz, adjustable internally;
30VA max. Installation Category II.
Operating Range: +5°C to 40°C, 20-80% RH.
Storage Range: –20°C to + 60°C.
Environmental: Indoor use at altitudes up to 2000m, Pollution Degree 2.
Options: IEEE-488 interface; 19 inch rack mounting kit.
Safety: Complies with EN61010-1.
EMC: Complies with EN61326.
3

EC Declaration of Conformity
We Thurlby Thandar Instruments Ltd
Glebe Road
Huntingdon
Cambridgeshire PE29 7DR
England
declare that the
TGR1040 1GHz Synthesised RF Signal Generator
meets the intent of the EMC Directive 2004/108/EC and the Low Voltage Directive 2006/95/EC.
Compliance was demonstrated by conformance to the following specifications which have been
listed in the Official Journal of the European Communities.
EMC
Emissions: a) EN61326-1 (2006) Radiated, Class B
b) EN61326-1 (2006) Conducted, Class B
c) EN61326-1 (2006) Harmonics, referring to EN61000-3-2 (2006)
Immunity: EN61326-1 (2006) Immunity Table 1, referring to:
a) EN61000-4-2 (1995) Electrostatic Discharge
b) EN61000-4-3 (2006) Electromagnetic Field
c) EN61000-4-11 (2004) Voltage Interrupt
d) EN61000-4-4 (2004) Fast Transient
e) EN61000-4-5 (2006) Surge
f) EN61000-4-6 (2007) Conducted RF
Performance levels achieved are detailed in the user manual.
Safety
EN61010-1 Installation Category II, Pollution Degree 2.
CHRIS WILDING
TECHNICAL DIRECTOR
1 May 2009
4

EMC
This instrument has been designed to meet the requirements of the EMC Directive 2004/108/EC.
Compliance was demonstrated by meeting the test limits of the following standards:
Emissions
EN61326-1 (2006) EMC product standard for Electrical Equipment for Measurement, Control and
Laboratory Use. Test limits used were:
a) Radiated: Class B
b) Conducted: Class B
c) Harmonics: EN61000-3-2 (2006) Class A; the instrument is Class A by product category.
Immunity
EN61326-1 (2006) EMC product standard for Electrical Equipment for Measurement, Control and
Laboratory Use.
Test methods, limits and performance achieved are shown below (requirement shown in
brackets):
a) EN61000-4-2 (1995) Electrostatic Discharge : 4kV air, 4kV contact, Performance A (B).
b) EN61000-4-3 (2006) Electromagnetic Field:
3V/m, 80% AM at 1kHz, 80MHz – 1GHz: Performance A (A) and 1.4GHz to 2GHz:
Performance A (A); 1V/m, 2.0GHz to 2.7GHz: Performance A (A).
c) EN61000-4-11 (2004) Voltage Interrupt: ½ cycle and 1 cycle, 0%: Performance A (B);
25 cycles, 70% and 250 cycles, 0%: Performance C (C).
d) EN61000-4-4 (2004) Fast Transient, 1kV peak (AC line), 0·5kV peak (signal connections),
Performance A (B).
e) EN61000-4-5 (2006) Surge, 0·5kV (line to line), 1kV (line to ground), Performance A (B).
f) EN61000-4-6 (2007) Conducted RF, 3V, 80% AM at 1kHz (AC line only; signal
connections <3m, therefore not tested), Performance A (A).
According to EN61326-1 the definitions of performance criteria are:
Performance criterion A: ‘During test normal performance within the specification limits.’
Performance criterion B: ‘During test, temporary degradation, or loss of function or
performance which is self-recovering’.
Performance criterion C: ‘During test, temporary degradation, or loss of function or
performance which requires operator intervention or system reset occurs.’
Cautions
To ensure continued compliance with the EMC directive observe the following precautions:
a) Connect the generator to other equipment using only high quality, double-screened cables.
b) After opening the case for any reason ensure that all signal and ground connections are
remade correctly and that case screws are correctly refitted and tightened.
c) In the event of part replacement becoming necessary, only use components of an identical
type, see the Service Manual.
5

Safety
This instrument is Safety Class I according to IEC classification and has been designed to meet
the requirements of EN61010-1 (Safety Requirements for Electrical Equipment for Measurement,
Control and Laboratory Use). It is an Installation Category II instrument intended for operation
from a normal single phase supply.
This instrument has been tested in accordance with EN61010-1 and has been supplied in a safe
condition. This instruction manual contains some information and warnings which have to be
followed by the user to ensure safe operation and to retain the instrument in a safe condition.
This instrument has been designed for indoor use in a Pollution Degree 2 environment in the
temperature range 5°C to 40°C, 20% - 80% RH (non-condensing). It may occasionally be
subjected to temperatures between +5°C and –10°C without degradation of its safety. Do not
operate while condensation is present.
Use of this instrument in a manner not specified by these instructions may impair the safety
protection provided. Do not operate the instrument outside its rated supply voltages or
environmental range.
WARNING! THIS INSTRUMENT MUST BE EARTHED
Any interruption of the mains earth conductor inside or outside the instrument will make the
instrument dangerous. Intentional interruption is prohibited. The protective action must not be
negated by the use of an extension cord without a protective conductor.
When the instrument is connected to its supply, terminals may be live and opening the covers or
removal of parts (except those to which access can be gained by hand) is likely to expose live
parts. The apparatus shall be disconnected from all voltage sources before it is opened for any
adjustment, replacement, maintenance or repair.
Any adjustment, maintenance and repair of the opened instrument under voltage shall be avoided
as far as possible and, if inevitable, shall be carried out only by a skilled person who is aware of
the hazard involved.
If the instrument is clearly defective, has been subject to mechanical damage, excessive moisture
or chemical corrosion the safety protection may be impaired and the apparatus should be
withdrawn from use and returned for checking and repair.
Make sure that only fuses with the required rated current and of the specified type are used for
replacement. The use of makeshift fuses and the short-circuiting of fuse holders is prohibited.
This instrument uses a Lithium button cell for non-volatile memory battery back-up; typical life is 5
years. In the event of replacement becoming necessary, replace only with a cell of the correct
type, i.e. 3V Li/Mn0220mm button cell type 2032. Exhausted cells must be disposed of carefully
in accordance with local regulations; do not cut open, incinerate, expose to temperatures above
60°C or attempt to recharge.
Do not wet the instrument when cleaning it and in particular use only a soft dry cloth to clean the
LCD window. The following symbols are used on the instrument and in this manual:-
Caution -refer to the accompanying documentation,
incorrect operation may damage the instrument.
terminal connected to chassis ground.
mains supply OFF.
l mains supply ON.
alternating current.
6

Installation
Check that the instrument operating voltage marked on the rear panel is suitable for the local
supply. Should it be necessary to change the operating voltage, proceed as follows:
1) Disconnect the instrument from all voltage sources.
2) Remove the screws which retain the top cover and lift off the cover.
3) Change the transformer connections following the appropriate diagram below:
4) Refit the cover and the secure with the same screws.
5) To comply with safety standard requirements the operating voltage marked on the rear panel
must be changed to clearly show the new voltage setting.
6) Change the fuse to one of the correct rating, see below.
Fuse
Ensure that the correct mains fuse is fitted for the set operating voltage. The correct mains fuse
types are:
for 230V operation: 250 mA (T) 250 V HRC
for 100V or 115V operation: 500 mA (T) 250 V HRC
To replace the fuse, disconnect the mains lead from the inlet socket and release the fuse drawer
below the socket pins by depressing both clips together, with miniature screwdrivers, so that the
drawer can be eased open. Change the fuse and replace the drawer.
The use of makeshift fuses or the short-circuiting of the fuse holder is prohibited.
Mains Lead
When a three core mains lead with bare ends is provided it should be connected as follows:-
Brown - Mains Live
Blue - Mains Neutral
Green / Yellow - Mains Earth
WARNING! THIS INSTRUMENT MUST BE EARTHED
Any interruption of the mains earth conductor inside or outside the instrument will make the
instrument dangerous. Intentional interruption is prohibited. The protective action must not be
negated by the use of an extension cord without a protective conductor.
Mounting
This instrument is suitable both for bench use and rack mounting. It is delivered with feet for
bench mounting. The front feet include a tilt mechanism for optimal panel angle.
A rack kit for mounting one or two of these Half-width 3U high units in a 19” rack is available from
the Manufacturers or their overseas agents.
7

Connections
Front Panel Connections
RF OUT
This is the 50Ωgenerator output. The maximum output is 500mVrms (+7dBm) into 50Ω. It can
tolerate a short circuit indefinitely.
Do not apply an external voltage to this output.
The Type N connector is a precision component that should be protected from excessive wear to
ensure that its RF characteristics (impedance and VSWR) are accurately maintained. If the
instrument is used in a manner that demands many connections/disconnections to and from the
RF OUT it is good practice to fit a male–to–female adaptor to the socket which can be replaced
periodically.
MOD IN
This is the external FM input. Input frequency range is 300Hz to 50kHz and input impedance is
nominally 100kΩ.
Do not apply external voltages exceeding ± 10V peak to this input.
Rear Panel Connections
RS232
9-pin D-connector compatible with the Thurlby Thandar ARC (Addressable RS232 Chain) system.
The pin connections are shown below:
Pin Name Description
1 - No internal Connection
2 TXD Transmitted data from instrument
3 RXD Received data to instrument
4 - No internal connection
5 GND Signal ground
6 - No internal connection
7 RXD2 Secondary received data (ARC use only)
8 TXD2 Secondary transmitted data (ARC use only)
9 GND Signal ground (ARC use only)
Pins 2, 3 and 5 may be used as a conventional RS232 interface with XON/XOFF handshaking.
Pins 7,8 and 9 are additionally used when the instrument is connected to the ARC system. Signal
grounds are connected to instrument ground. The ARC address is set from the front panel using
the Utilities menu.
GPIB (IEEE-488)
The GPIB interface is an option. It is not isolated; the GPIB signal grounds are connected to the
instrument ground.
The implemented subsets are:
SH1 AH1 T6 TE0 L4 LE0 SR1 RL1 PP1 DC1 DT0 C0 E2
The GPIB address is set from the front panel using the Utilities menu.
8

Operation
General
This section is a general introduction to the operation of the generator, intended to be read before
using the instrument for the first time.
Switching On
The power switch is located at the bottom left of the front panel.
At power up the generator displays the installed software revision for 2 seconds before reverting
to the main menu; the RF OUT output is off but all the other settings are the same as when the
instrument was last powered down. Should an error with the battery-backed RAM be encountered
at power up a message will be displayed, see the Error Messages section.
The basic generator parameters can all be set from this main menu as described in the following
sections. The output is switched on with the RF OUT key; the ON lamp will light to show that the
output is on.
Keyboard Principles
The keys can be considered in the following groups:
• The numeric/unit keys permit direct entry of a value for the parameter currently selected
(indicated by thecursor beside the parameter). Thus, with frequency selected,
123.456 MHz is set by keying 1, 2, 3, • , 4, 5, 6 MHz. The parameter actually changes only
when the units key (dB, MHz, etc.) is pressed.
FREQUENCY can be entered in kHz or MHz but will always be displayed in MHz. LEVEL can
be entered in dBm, mV or µV; mV values below 1.00mV will be displayed in µV and µV values
above 1000µV will be displayed in mV. With thecursor set to LEVEL the value displayed
can be switched from dBm to µV/mV and vice-versa by pressing the appropriate key.
To enter negative numbers (for dB) the ± key can be used at any time during the number
entry.
ESCAPE aborts the entry and leaves the parameter at its previous setting.
• To the left of the numeric keys are the 5 parameter keys which select the parameter to be
changed; thecursor moves to the selected parameter and that parameter can then be
changed as described above.
Next to the MODULATION SELECT key is the MODULATION ON/OFF key which turns
modulation on and off with alternate presses; the MODULATION lamp lights when modulation
is on.
• The FIELD keys provide an alternative means of moving thecursor between parameters on
a menu. The rotary control and thekeys below it provide alternative means of
incrementing/decrementing the value of the currently selected parameter (for FREQUENCY
and LEVEL) or stepping through the parameter settings (for ADDRESS, etc.). When
incrementing/decrementing frequency and level the parameter value changes in steps set up
on the STEP SIZE menu, see Step Size section. During numeric entries thekey also acts
as a backspace/delete.
• The UTILITIES key selects the Utilities menu which gives access to the stored set-ups and
remote control parameters. The LOCAL key returns the instrument to local (keyboard) control
from remote control.
• The EXECUTE key is used to confirm operations other than numeric parameter entries,
e.g. during store and recall of set-ups.
9

Step Size
When changing the FREQUENCY or LEVEL using the rotary control orkeys the size of
each step change will be that previously set on the Step Size menu. The default FREQUENCY
step is 10 MHz. The defaults for the two separate LEVEL step sizes are 10dB and 10mV; the
active LEVEL step size is the one currently displayed in the Step Size menu. Note that either
LEVEL step setting can be used with either LEVEL display mode; i.e. mV steps can be used in a
dB display and vice-versa. However, it will generally be most useful to use dB steps in a dB level
display and µV/mV steps in a µV/mV display.
To change the step size, select the STEP SIZE menu and move theselection cursor to the
required parameter with the FIELD keys. Alternatively, because the cursor automatically points to
the step size of the most recently selected main menu parameter, pressing FREQUENCY
followed by STEP SIZE will set thecursor to frequency step size and pressing LEVEL followed
by STEP SIZE will set the cursor to level step size.
FREQUENCY steps can be entered directly from the keyboard in kHz or MHz but will always be
displayed in MHz. The smallest step that can be set is 1kHz and this is the amount by which the
step is changed if the rotary control orkeys are used; large changes in step size are
therefore made most quickly by direct keyboard entry.
LEVEL steps can be entered directly from the keyboard in dB or µV/mV; separate step sizes are
stored for dB and µV/mV and the choice of units will determine which of the two LEVEL steps is
changed. The active LEVEL step size is the one currently displayed; pressing dB or µV/mV will
switch between the two without changing either. Note that mV values below 1.00mV will be
displayed in µV and µV values above 1000µV will be displayed in mV. The smallest step size that
can be set is 0.1dB or 0.01µV; when using the rotary control orkeys to set step size the
amount by which the step is changed is 0 .1dB for dB steps or 1 least significant digit for µV/mV
steps.
Having set the step size, return to the main menu by pressing FREQUENCY or LEVEL, etc.
Setting Frequency
Set thecursor to FREQUENCY on the main menu by pressing the FREQUENCY key. The
generator frequency can then be set directly from the keyboard, in kHz or MHz, or changed using
the rotary control orkeys. Refer to Keyboard Principles for further information on keyboard
entries and to Step Size for setting the rotary control andkey increment size.
Note that when an increment would have taken the frequency above the instrument's maximum,
the setting becomes 1000 MHz. The next decrement returns the frequency to the last in-range
setting and further decrements decrease the frequency by the specified step size. Similarly when
a decrement would have taken the frequency below the instrument's minimum the setting
becomes 10 MHz and the next increment returns the frequency to the last in-range setting, etc.
Setting Level
Set thecursor to LEVEL on the main menu by pressing the LEVEL key. The output level can
then be set directly from the keyboard, in dBm or µV/mV, or changed using the rotary control or
keys. Refer to Keyboard Principles for further information on keyboard entries and to Step
Size for setting the rotary control andkey increment size.
Note that when an increment would have taken the level above the instrument's maximum output
the setting becomes +7dBm (or 500mV). The next decrement returns the level to the last in-range
setting and further decrements reduce the level by the specified step size. Similarly when a
decrement would have taken the level below the instrument's minimum the setting becomes
–127dBm (or 0.1µV) and the next increment returns the setting to the last in-range setting, etc.
10

Modulation
The generator can be set for either internal or external FM. With theselection cursor in the
MODULATION field of the main menu the modulation can be switched between INTERNAL and
EXTERNAL with alternate presses of the SELECT MODULATION key, or by using the rotary
control orkeys.
Internal modulation is fixed at 1 kHz. External modulation requires a modulating signal in the
range 300 Hz to 50 kHz to be applied to the EXT IN input.
Peak deviation can be set from 0.5 kHz to 100 kHz in 0.5 kHz steps. With theselection cursor
in the PEAK DEVIATION field of the main menu the peak deviation can be set directly from the
keyboard, in kHz or MHz, or changed using the rotary control orkeys. Refer to Keyboard
Principles for further information on keyboard entries. With external modulation, the specified
peak deviation is achieved with a 1Vrms sinewave modulating signal.
The selected modulation source can be switched on and off at any time using the MODULATION
ON/OFF key; the MODULATION lamp lights when modulation is on.
The default modulation settings are internal modulation, 50 kHz peak deviation, modulation off.
Storing and Recalling Set-ups
Complete instrument set-ups can be stored or recalled from non-volatile RAM using the STORE
and RECALL facilities on the Utilities menu, accessed by pressing the UTILITIES key.
With theselection cursor in the STORE field of the Utilities menu the store to be used can be
selected with the rotary control orkeys. Nine stores, numbered 1 to 9 inclusive are
available. Select the required store and press the EXECUTE key; the display requests that you
press EXECUTE again to confirm the operation (or any other key to cancel). A set-up already in
that store will be overwritten. The status of the RF OUT is ignored; when a store is recalled the
RF OUT is always off.
With thecursor in the RECALL field of the Utilities menu a previously stored set-up, or the
factory defaults, can be recalled. Select the required store, or DEFAULTS for factory defaults, and
press the EXECUTE key; the display requests that you press EXECUTE again to confirm (or any
other key to cancel). If there is no valid data in the specified store the message 'NO VALID DATA
IN STORE' will be displayed and the set-up will remain unchanged.
11

Remote Operation
The instrument can be remotely controlled via its RS232 or GPIB interfaces. When using RS232
it can either be the only instrument connected to the controller or it can be part of an Addressable
RS232 Chain (ARC) which permits up to 32 instruments to be addressed from one RS232 port.
Some of the following sections are general and apply to all 3 modes (single instrument RS232,
ARC and GPIB); others are clearly only relevant to a particular interface or mode. It is only
necessary to read the general sections plus those specific to the intended remote control mode.
Remote command format and the remote commands themselves are detailed in the Remote
Commands chapter.
Address and Baud Rate Selection
For successful operation, each instrument connected to the GPIB or Addressable RS232 Chain
(ARC) must be assigned a unique address and, in the case of addressable RS232, all must be
set to the same Baud rate.
The instrument's remote address for operation on both the GPIB and RS232 interfaces is set on
the Utilities menu, accessed by pressing the UTILITIES key. With theselection cursor in the
ADDRESS field the address can be changed using the rotary control or keys. On this
instrument addresses 0 to 30 inclusive are allowed; the factory default is address 1. The address
setting is ignored in single instrument RS232 operation.
With theselection cursor in the REMOTE field, the rotary control orkeys can be used to
select GPIB or RS232 with Baud rates of between 300 and 19200; the factory default selection is
RS232 at 9600 Baud.
Remote/Local Operation
At power-on the instrument will be in the local state with the REMOTE lamp off. In this state all
keyboard operations are possible. When the instrument is addressed to listen and a command is
received the remote state will be entered and the REMOTE lamp will be turned on. In this state
the keyboard is locked out and remote commands only will be processed. The instrument may be
returned to the local state by pressing the LOCAL key; however, the effect of this action will only
remain until the instrument is addressed again or receives another character from the interface,
when the remote state will once again be entered.
RS232 Interface
RS232 Interface Connector
The 9-way D-type serial interface connector is located on the instrument rear panel. The pin
connections are as shown below:
Pin Name Description
1 - No internal connection
2 TXD Transmitted data from instrument
3 RXD Received data to instrument
4 - No internal connection
5 GND Signal ground
6 - No internal connection
7 RXD2 Secondary received data (addressable RS232 only)
8 TXD2 Secondary transmitted data (addressable RS232 only)
9 GND Signal ground (addressable RS232 only)
Single Instrument RS232 Connections
For single instrument remote control only pins 2, 3 and 5 are connected to the PC. However, for
correct operation links must be made in the connector at the PC end between pins 1, 4 and 6 and
between pins 7 and 8, see diagram. Pins 7 and 8 of the instrument must not be connected to the
PC, i.e. do not use a fully wired 9–way cable.
12

Baud Rate is set as described above in Address and Baud Rate Selection; the other parameters
are fixed as follows:
Start Bits: 1 Parity: None
Data Bits: 8 Stop Bits: 1
Addressable RS232 Connections
For addressable RS232 operation pins 7, 8 and 9 of the instrument connector are also used.
Using a simple cable assembly, a 'daisy chain' connection system between any number of
instruments, up to the maximum of 32 can be made, as shown below:
The daisy chain consists of the transmit data (TXD), receive date (RXD) and signal ground lines
only. There are no control/handshake lines. This makes XON/XOFF protocol essential and allows
the inter-connection between instruments to contain just 3 wires. The wiring of the adaptor cable
is shown below:
All instruments on the interface must be set to the same baud rate and all must be powered on,
otherwise instruments further down the daisy chain will not receive any data or commands.
The other parameters are fixed as follows:
Start Bits: 1 Parity: None
Data Bits: 8 Stop Bits: 1
13

RS232 Character Set
Because of the need for XON/XOFF handshake it is possible to send ASCII coded data only;
binary blocks are not allowed. Bit 7 of ASCII codes is ignored, i.e. assumed to be low. No
distinction is made between upper and lower case characters in command mnemonics and they
may be freely mixed. The ASCII codes below 20H (space) are reserved for addressable RS232
interface control. In this manual 20H, etc. means 20 in hexadecimal
Addressable RS232 (ARC) Interface Control Codes
All instruments intended for use on the ARC bus use the following set of interface control codes.
Codes between 00H and 1FH which are not listed here as having a particular meaning are
reserved for future use and will be ignored. Mixing interface control codes inside instrument
commands is not allowed except as stated below for CR and LF codes and XON and XOFF
codes.
When an instrument is first powered on it will automatically enter the Non- Addressable mode. In
this mode the instrument is not addressable and will not respond to any address commands. This
allows the instrument to function as a normal RS232 controllable device. This mode may be
locked by sending the Lock Non-Addressable mode control code, 04H. The controller and
instrument can now freely use all 8 bit codes and binary blocks but all interface control codes are
ignored. To return to addressable mode the instrument must be powered off.
To enable addressable mode after an instrument has been powered on the Set Addressable
Mode control code, 02H, must be sent. This will then enable all instruments connected to the
ARC bus to respond to all interface control codes. To return to Non-Addressable mode the Lock
Non-Addressable mode control code must be sent which will disable addressable mode until the
instruments are powered off.
Before an instrument is sent a command it must be addressed to listen by sending the Listen
Address control code, 12H, followed by a single character which has the lower 5 bits
corresponding to the unique address of the required instrument, e.g. the codes A-Z or a-z give the
addresses 1-26 inclusive while @ is address 0 and so on. Once addressed to listen the
instrument will read and act upon any commands sent until the listen mode is cancelled.
Because of the asynchronous nature of the interface it is necessary for the controller to be
informed that an instrument has accepted the listen address sequence and is ready to receive
commands. The controller will therefore wait for Acknowledge code, 06H, before sending any
commands, The addressed instrument will provide this Acknowledge. The controller should time-
out and try again if no Acknowledge is received within 5 seconds.
Listen mode will be cancelled by any of the following interface control codes being received:
12H Listen Address followed by an address not belonging to this instrument.
14H Talk Address for any instrument.
03H Universal Unaddress control code.
04H Lock Non-Addressable mode control code.
18H Universal Device Clear.
Before a response can be read from an instrument it must be addressed to talk by sending the
Talk Address control code,14H, followed by a single character which has the lower 5 bits
corresponding to the unique address of the required instrument, as for the listen address control
code above. Once addressed to talk the instrument will send the response message it has
available, if any, and then exit the talk addressed state. Only one response message will be sent
each time the instrument is addressed to talk.
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Talk mode will be cancelled by any of the following interface control codes being received:
12H Listen Address for any instrument.
14H Talk Address followed by an address not belonging to this instrument.
03H Universal Unaddress control code.
04H Lock Non-Addressable mode control code.
18H Universal Device Clear.
Talk mode will also be cancelled when the instrument has completed sending a response
message or has nothing to say.
The interface code 0AH (LF) is the universal command and response terminator; it must be the
last code sent in all commands and will be the last code sent in all responses.
The interface code 0DH (CR) may be used as required to aid the formatting of commands; it will
be ignored by all instruments. Most instruments will terminate responses with CR followed by LF.
The interface code 13H (XOFF) may be sent at any time by a listener (instrument or controller) to
suspend the output of a talker. The listener must send 11H (XON) before the talker will resume
sending. This is the only form of handshake control supported by ARC.
Full List of Addressable RS232 (ARC) Interface Control Codes
02H Set Addressable Mode.
03H Universal Unaddress control code.
04H Lock Non-Addressable mode control code.
06H Acknowledge that listen address received.
0AH Line Feed (LF); used as the universal command and response terminator.
0DH Carriage Return (CR); formatting code, otherwise ignored.
11H Restart transmission (XON).
12H Listen Address - must be followed by an address belonging to the required instrument.
13H Stop transmission (XOFF).
14H Talk Address - must be followed by an address belonging to the required instrument.
18H Universal Device Clear.
GPIB Interface
When the GPIB interface is fitted the 24-way GPIB connector is located on the instrument rear
panel. The pin connections are as specified in IEEE Std. 488.1-1987 and the instrument
complies with IEEE Std. 488.1-1987 and IEEE Std. 488.2-1987.
GPIB Subsets
This instrument contains the following IEEE 488.1 subsets:
Source Handshake SH1
Acceptor Handshake AH1
Talker T6
Listener L4
Service Request SR1
Remote Local RL1
Parallel Poll PP1
Device Clear DC1
Device Trigger DT0
Controller C0
Electrical Interface E2
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GPIB IEEE Std. 488.2 Error Handling
The IEEE 488.2 UNTERMINATED error (addressed to talk with nothing to say) is handled as follows.
If the instrument is addressed to talk and the response formatter is inactive and the input queue is
empty then the UNTERMINATED error is generated. This will cause the Query Error bit to be set in
the Standard Event Status Register, a value of 3 to be placed in the Query Error Register and the
parser to be reset. See the Status Reporting section for further information.
The IEEE 488.2 INTERRUPTED error is handled as follows. If the response formatter is waiting to
send a response message and a <PROGRAM MESSAGE TERMINATOR> has been read by the parser
or the input queue contains more than one END message then the instrument has been
INTERRUPTED and an error is generated. This will cause the Query Error bit to be set in the
Standard Event Status Register, a value of 1 to be placed in the Query Error Register and the
response formatter to be reset thus clearing the output queue. The parser will then start parsing
the next <PROGRAM MESSAGE UNIT> from the input queue. See the Status Reporting section for
further information.
The IEEE 488.2 DEADLOCK error is handled as follows. If the response formatter is waiting to send
a response message and the input queue becomes full then the instrument enters the DEADLOCK
state and an error is generated. This will cause the Query Error bit to be set in the Standard Event
Status Register, a value of 2 to be placed in the Query Error Register and the response formatter
to be reset thus clearing the output queue. The parser will then start parsing the next <PROGRAM
MESSAGE UNIT> from the input queue. See the Status Reporting section for further information.
GPIB Parallel Poll
Complete parallel poll capabilities are offered on this generator. The Parallel Poll Enable Register
is set to specify which bits in the Status Byte Register are to be used to form the ist local message
The Parallel Poll Enable Register is set by the *PRE <nrf> command and read by the *PRE?
command. The value in the Parallel Poll Enable Register is ANDed with the Status Byte Register;
if the result is zero then the value of ist is 0 otherwise the value of ist is 1.
The instrument must also be configured so that the value of ist can be returned to the controller
during a parallel poll operation. The instrument is configured by the controller sending a Parallel
Poll Configure command (PPC) followed by a Parallel Poll Enable command (PPE). The bits in
the PPE command are shown below:
bit 7 = X don't care
bit 6 = 1
bit 5 = 1 Parallel poll enable
bit 4 = 0
bit 3 = Sense sense of the response bit; 0 = low, 1 = high
bit 2 = ?
bit 1 = ? bit position of the response
bit 0 = ?
Example. To return the RQS bit (bit 6 of the Status Byte Register) as a 1 when true and a 0 when
false in bit position 1 in response to a parallel poll operation send the following
commands
*PRE 64<pmt>, then PPC followed by 69H (PPE)
The parallel poll response from the generator will then be 00H if RQS is 0 and 01H if RQS
is 1.
During parallel poll response the DIO interface lines are resistively terminated (passive
termination). This allows multiple devices to share the same response bit position in either wired-
AND or wired-OR configuration, see IEEE 488.1 for more information.
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Status Reporting
This section describes the complete status model of the instrument. Note that some registers are
specific to the GPIB section of the instrument and are of limited use in an RS232 environment.
Standard Event Status and Standard Event Status Enable Registers
These two registers are implemented as required by the IEEE std. 488.2.
Any bits set in the Standard Event Status Register which correspond to bits set in the Standard
Event Status Enable Register will cause the ESB bit to be set in the Status Byte Register.
The Standard Event Status Register is read and cleared by the *ESR? command. The Standard
Event Status Enable register is set by the *ESE <nrf> command and read by the *ESE?
command.
Bit 7 - Power On. Set when power is first applied to the instrument.
Bit 6 - Not used.
Bit 5 - Command Error. Set when a syntax type error is detected in a command from the bus.
The parser is reset and parsing continues at the next byte in the input stream.
Bit 4 - Execution Error. Set when an error is encountered while attempting to execute a
completely parsed command. The appropriate error number will be reported in the
Execution Error Register.
Bit 3 - Not used.
Bit 2 - Query Error. Set when a query error occurs. The appropriate error number will be
reported in the Query Error Register as listed below.
1. Interrupted error
2. Deadlock error
3. Unterminated error
Bit 1 - Not used.
Bit 0 - Operation Complete. Set in response to the *OPC command.
Status Byte Register and Service Request Enable Register
These two registers are implemented as required by the IEEE std. 488.2.
Any bits set in the Status Byte Register which correspond to bits set in the Service Request
Enable Register will cause the RQS/MSS bit to be set in the Status Byte Register, thus generating
a Service Request on the bus.
The Status Byte Register is read either by the *STB? command, which will return MSS in bit 6, or
by a Serial Poll which will return RQS in bit 6. The Service Request Enable register is set by the
*SRE <nrf> command and read by the *SRE? command.
Bit 7 - Not used.
Bit 6 - RQS/MSS. This bit, as defined by IEEE Std. 488.2, contains both the Requesting
Service message and the Master Status Summary message. RQS is returned in
response to a Serial Poll and MSS is returned in response to the *STB? command.
Bit 5 - ESB. The Event Status Bit. This bit is set if any bits set in the Standard Event Status
Register correspond to bits set in the Standard Event Status Enable Register.
Bit 4 - MAV. The Message Available Bit. This will be set when the instrument has a response
message formatted and ready to send to the controller. The bit will be cleared after the
Response Message Terminator has been sent.
Bit 3 - Not used.
Bit 2 - Not used.
Bit 1 - Not used.
Bit 0 - Not used.
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Status Model
Power on Settings
The following instrument status values are set at power on:
Status Byte Register = 0
Service Request Enable Register ✝= 0
Standard Event Status Register = 128 (pon bit set)
Standard Event Status Enable Register ✝= 0
Execution Error Register = 0
Query Error Register = 0
Parallel Poll Enable Register ✝= 0
✝ Registers marked thus are specific to the GPIB section of the instrument and are of limited use
in an RS232 environment.
The instrument will be in local state with the keyboard active.
The instrument parameters at power on are the same as at last switch off with the exception of
RF OUT which is always off.
If for any reason an error is detected at power up in the non-volatile ram a warning will be issued
and all settings will be returned to their default states as for a *RST command.
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Remote Commands
RS232 Remote Command Formats
Serial input to the instrument is buffered in a 256 byte input queue which is filled, under interrupt,
in a manner transparent to all other instrument operations. The instrument will send XOFF when
approximately 200 characters are in the queue. XON will be sent when approximately 100 free
spaces become available in the queue after XOFF was sent. This queue contains raw (un-
parsed) data which is taken, by the parser, as required. Commands (and queries) are executed in
order and the parser will not start a new command until any previous command or query is
complete. In non–addressable RS232 mode responses to commands or queries are sent
immediately; there is no output queue. In addressable mode the response formatter will wait
indefinitely if necessary, until the instrument is addressed to talk and the complete response
message has been sent, before the parser is allowed to start the next command in the input
queue.
Commands must be sent as specified in the commands list and must be terminated with the
command terminator code 0AH (Line Feed, LF). Commands may be sent in groups with
individual commands separated from each other by the code 3BH (;). The group must be
terminated with command terminator 0AH (Line Feed, LF).
Responses from the instrument to the controller are sent as specified in the commands list. Each
response is terminated by 0DH (Carriage Return, CR) followed by 0AH (Line Feed, LF).
<WHITE SPACE> is defined as character codes 00H to 20H inclusive with the exception of those
which are specified as Addressable RS232 (ARC) control codes.
<WHITE SPACE> is ignored except in command identifiers. e.g. '*C LS' is not equivalent to '*CLS'.
The high bit of all characters is ignored.
The commands are case insensitive.
GPIB Remote Command Formats
GPIB input to the instrument is buffered in a 256 byte input queue which is filled, under interrupt,
in a manner transparent to all other instrument operations. The queue contains raw (un-parsed)
data which is taken, by the parser, as required. Commands (and queries) are executed in order
and the parser will not start a new command until any previous command or query is complete.
There is no output queue which means that the response formatter will wait, indefinitely if
necessary, until the instrument is addressed to talk and the complete response message has
been sent, before the parser is allowed to start the next command in the input queue.
Commands are sent as <PROGRAM MESSAGES> by the controller, each message consisting of zero
or more <PROGRAM MESSAGE UNIT> elements separated by <PROGRAM MESSAGE UNIT SEPARATOR>
elements.
A <PROGRAM MESSAGE UNIT> is any of the commands in the remote commands list.
A <PROGRAM MESSAGE UNIT SEPARATOR> is the semi-colon character ';' (3BH).
<PROGRAM MESSAGES> are separated by <PROGRAM MESSAGE TERMINATOR> elements which may
be any of the following:
NL The new line character (0AH)
NL^END The new line character with the END message
^END The END message with the last character of the message
Responses from the instrument to the controller are sent as <RESPONSE MESSAGES>. A
<RESPONSE MESSAGE> consists of one <RESPONSE MESSAGE UNIT> followed by a <RESPONSE
MESSAGE TERMINATOR>.
A <RESPONSE MESSAGE TERMINATOR> is the new line character with the END message NL^END.
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