Time Electronics 9814 User manual

9814
Programmable
D.C. Voltage Calibrator
Technical Manual
Time Electronics Ltd
Unit 11 Botany Industrial Estate
Tonbridge, Kent, TN9 1RH
Tel: [phone] Fax: [phone]
E-Mail: [email protected]
Web Site: www.TimeElectronics.co.uk
V3 10/07/03

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Contents
Page
1) Introduction ............................................................................... 3
2) Specifications ............................................................................ 4
3) Front Panel Controls ................................................................. 5
4) Local Operation ......................................................................... 6
5) Remote Operation ..................................................................... 10
6) Fault Diagnosis.......................................................................... 19
7) Technical Description ............................................................... 22
8) Calibration.................................................................................. 24
9) Spare Parts ................................................................................ 26
10) Guarantee and Servicing .......................................................... 27
All Time Electronics' instruments are subject to continuous development
and improvement and in consequence may incorporate minor detail
changes from the information contained herein.

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Section 1 - Introduction
The 9814 is a high performance programmable D.C. voltage calibrator. By
combining the latest microprocessor and linear circuit technology exceptional
long term stability has been achieved. Computer selection of the basic refer-
ence device combined with high performance precision resistors ensure a
guaranteed 50 ppm/year stability.
The 9814 therefore maintains Time Electronics’ high standard of stability and
allows the customer complete confidence in the instruments long term per-
formance. Construction is modular and is based on the standard Euro card
frame. Each main section i.e. Microprocessor control, IEEE interface, D-A
converter, Reference amplifier etc. are located on a separate plug in Euro
board. All boards are easily accessible form the rear of the instrument.
The 9814 can if required be operated in a manual mode with all controls lo-
cated on the front panel.

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Section 2 - Specifications
Output: 0 to 10V in 4 ranges
D.C. Accuracy:
10V & 1V Ranges: 0.01% of setting, +/- 0.001% of range, +/-3uV
100mV & 10mV ranges: 0.02% of setting, +/- 0.005% of range, +/-2uV.
Output resistance: 10 mohms on 10V & 1V ranges.
10 ohms on 100mV and 10mV ranges.
Output current: Internally adjustable between 200mA and 20mA
on 1V and 10V ranges. On the 100mV and 10mV
ranges the limit is the short circuit current, but
loads of greater than 1 Kohm will cause errors of
greater than 0.1% error in the output voltage.
Output Polarity: True bi-poplar output is provided. i.e. the ’Lo’ output
terminal can remain at earth for all output values and
and polarities. This eliminates common mode errors
or the need to reverse the input connections.
Temperature coefficient: 20ppm/°C on all ranges.
Noise: 4ppm of full scale.
Overload: Continuous short circuit can be withstood on all
ranges.
Settling time: Less than 1ms between 0 and full scale.
Less than 50ms with range change.
Power requirements: 220 - 240V A.C. 50 Hz OR 110 - 120V A.C. 60 Hz
Switch selectable.
Interface: IEEE-488.
Dimensions: 123 x 632 x 110mm. Weight 5Kg.

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Section 3 - Front Panel Controls
1) 2 LEDS - A) ON Illuminates when unit is on
B) LOCAL Illuminates when unit is in LOCAL mode
2) 2 PRESS SWITCHES - A) MAINS / ON
B) LOCAL / REMOTE
3) 20 PRESS SWITCHES - Select range, output level and polarity
4) 20 LED STATUS - Indicates range and operating mode.
5) 8 DIGIT LED - Shows output and polarity
6) 3 TERMINALS - Output
7) 2 LEDS - A) REMOTE Illuminates when REMOTE is selected.
- B) DATA Flashes once when a complete command
has been received.

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Section 4 - Local Operation
Mains Voltage Selection
Situated at the rear of the 9814 on the power module, are the mains inlet socket, two
fuses and the voltage selector. The mains voltage is displayed in a small window. Ac-
cess to the fuses and mains selector is via a lever down flap. To change the mains
voltage, switch off the mains, open the flap and rotate the selector to the required
value. Replace the selector and close the flap.
Switching On
At Power on, the 9814 will automatically switch to the 10mV D.C. range and select
zero output.
If ERROR 6 is displayed, the calibration factors have been lost and the unit will need to
be recalibrated. See section 8.
Important Note:-
The 9814 should not normally be operated with the IEEE address 0 or 16 set, or with
the calibration key in. These addresses are reserved for autocal recalibration. Opera-
tion in this condition may result in the loss of the calibration factors.
Operation
Manual operation of the 9814 is always enabled by setting the instrument into LOCAL
mode and selecting the required function.
Selecting a range and output value
1) Press SELECT
2) Press a RANGE key. (10V to 10mV).
3) Press + or—switch to select output polarity.
4) Press switches marked with upward or downward arrows to increment or decre-
ment the output.
5) Full scale or zero output can be selected directly by pressing the F.S. or zero
keys.
Zero Offset and Deviation
(a) Offset
Set up the offset required as an output as described above. Then press SELECT fol-
lowed by ZERO. This value will then be stored and added to or subtracted from (if a
negative offset was set) any output value subsequently selected.
During the period when the offset is in use, the left hand digit of the display will show a
flashing horizontal bar. To cancel the offset, press SELECT and re-select a range.

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(b) Percentage deviation
This can be applied to the output as follows:-
Press the DEV key. The display will change to a 4-digit format indicating percentage de-
viation. This can be set in the range +9.999% to –9.999% by pressing the arrowed in-
crement or decrement switches. To return to the normal output display, press the DEV
key again. When a deviation has been set, the LED on the DEV key will flash as a re-
minder that a deviation is being applied to the output.
To cancel deviation mode, press SELECT and re-select a range, or zero the deviation
and press the deviation key to return to the normal output display.
Selecting a user function
Operation of the SELECT key followed by DEV offers 2 user selectable functions. The
user function display shows the functions on digits 2, 4, 6, 7 and 8 reading left to right.
Only digits 6 and 8 are used on the 9814. The mode is incremented using the arrowed
key beneath the function digit. The following paragraphs correspond to digit numbers
and explain each of the functions and associated modes.
Default display:-
0 0 301
Digit 6 : Keyboard Operating Modes
This function allows 4 different modes of carry-over with or without auto-repeat as
shown in Table 4.2. Selection of the carry-over function enables a 9 to 10 carry-over.
Without it, the carry-over will be 9 to 0.
Table 4.2 Keyboard Operating Modes
MODE CARRY AUTO
OVER REPEAT
0 N N
1 Y N
2 N Y
3 Y Y
The auto-repeat facility, available in modes 2 or 3, gives continuous repetition of the
held down key.

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Digit 8 : Output error modes
The 9814 will display ‘OP ERROR’ (output error) when it is unable to drive the load with
the selected output.
NOTE
Output errors are not detected on the 10mV and 100mV ranges.
The user can select one of 4 ways in which the 9814 will respond to an output error de-
tailed below.
Mode 1. The output will be set to zero immediately and ‘OP ERROR’ displayed. To
continue using the 9814, the fault must be rectified and the output re-selected. The dis-
play will then show the re-selected value.
Mode 2. The output will be set to zero immediately and ‘OP ERROR’ displayed.
The output will be reinstated if the overload disappears and the previous output value
displayed.
Mode 3. Upon detection of an error, the 9814 will wait for 0.5 seconds before setting the
output to zero and displaying ‘OP ERROR’. The fault must be rectified and the output re-
selected.
Mode 4. The 9814 will continue to drive the output circuits and ‘OP ERROR’ will be dis-
played after 0.5 seconds.
Self Test Mode
To select self test mode, set all 8 IEEE switches (on rear of 9814) to the ON position be-
fore switching on the instrument.
When switched on, the 9814 will carry out an internal test sequence as follows. Each
segment of the 8 digit display will light in turn, followed by all the front panel LED’s (with
the exception of the F.S., ZERO, + & - LEDS which are not tested). If no errors are de-
tected, the word PASS will appear on the display.
If an error is detected, the word ERROR followed with a number from 1 to 6 will be dis-
played. The meaning of these numbers is explained in Table 4.3
Table 4.3. Fault displays
NUMBER FAULT REPLACE
1 RAM Processor Board
2 GPIA IEEE Board
4 PIA Processor Board (IC1 6821)
5 PIA Processor Board (IC2 6821
6 CAL RAM Calibration RAM (X2816)

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See section 7 for details of board replacement.
* Error 6
This test is carried out every time the 9814 is switched on regardless of the IEEE ad-
dress. If the calibration factors are corrupted ERROR 6 will be displayed. To clear this
condition, run the self test with the calibration key plugged in. This exercise leaves the
cal ram empty so re-calibration is required. (see section 8).
If ERROR 6 persists, then change the non-volatile RAM.
NOTE: Running self test with the calibration key plugged in will result in the loss of cali-
bration data.
To exit from self test mode, turn the 9814 off, set the unit address on the IEEE switches
and switch on again.

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Section 5 - Remote Operation
Introduction
The IEEE-488 interface sometimes called GPIB (General Purpose Interface Bus) or
HPIB (Hewlett Packard Interface Bus) allows remote control of the 9814 by a suitable
computer. Repetitive calibration work can be speedily and accurately carried out giving
printed results if required.
The IEEE-488 defines a complete interface system for the interconnecting of instru-
ments and computers using a bit parallel, byte serial bi-direction bus.
Protocols, connections and cables are also defined, enabling computer controlled sys-
tems to be quickly realised.
The main limitations of the IEEE are:-
1). A maximum of 15 devices on the bus.
2). The maximum bus length should not be greater than 20m or number of devices x2,
which ever is the shorter.
Data Transfer and Device Addressing
Before a controller can send data it has to identify the recipient. Each device on the
IEEE is given an address to which it will respond when called by the controller in this
way data can be transferred between selected devices in an orderly manner. The rate at
which it is transferred is controlled by hand shake signals, the speed being governed by
the slowest device active on the bus. Set baud rates are unnecessary with the system.
Further information on the IEEE-488 can be found in the condensed description of the
Hewlett Packard Interface Bus.
IEEE Cables/Connectors
The IEEE-488 cable contains 24 wires terminated at both ends with identical plug/
sockets which allow for daisy - chaining of additional cables to extend the bus. See Ta-
ble 5.1 for details of connections.
Cables used on IEEE systems are available in various lengths to suit different layouts.
Manufacturer/Supplier Part No. Length
Belden 9642 1m
Belden 9643 2m
Belden 9644 4m
Belden 9645 8m
Time Electronics 9596 1m
Time Electronics 9597 2m

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IEC Bus Connections
A user requiring to connect the 9814 to a European standard bus (IEC), must
be aware of the differences in connector pin assignments from the IEEE bus
and provide a suitable interface. Table 5.1 compares the pin designations for
each standard.
IEEE Connector
The pin connections and dimensions of the IEEE connector are illustrated in
Table 5.1 and Fig. 5.1

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IEEE Standard IEC Standard
PIN PIN
1 D101 1 D101
2 D102 2 D102
3 D103 3 D103
4 D104 4 D104
5 EOI 5 REN
6 DAV 6 EOI
7 NRFD 7 DAV
8 NDAC 8 NRFD
9 IFC 9 NDAC
10 SRQ 10 IFC
11 ATN 11 SRQ
12 SHIELD 12 ATN
13 D105 13 SHIELD
14 D106 14 D105
15 D107 15 D106
16 D108 16 D107
17 REN 17 D108
18 GND 6 18 GND 5
19 GND 7 19 GND 6
20 GND 8 20 GND 7
21 GND 9 21 GND 8
22 GND 10 22 GND 9
23 GND 11 23 GND 10
24 LOGIC END 24 GND 11
IEEE Address selection
Before operating the 9814 over the IEEE, set the address on the rear of the unit to the
required address and operating mode.
Addresses 0 and 16 are reserved for recalibration in AUTO-CAL mode and should not
be used unless recalibrating the instrument. Address 31 is used to select self test mode.
The eight switches are read only when the 9814 is first switched ‘ON’. Therefore it is
necessary to turn the 9814 ‘OFF’ if a new IEEE address is required.
Table 5.1 Comparison of pin designations IEEE/IEC

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Table 5.2 IEEE Address selection
SWITCH DECIMAL SWITCH DECIMAL
SETTING ADDRESS SETTING ADDRESS
0 0 0 0 0 0 1 0 0 0 0 16
0 0 0 0 1 1 1 0 0 0 1 17
0 0 0 1 0 2 1 0 0 1 0 18
0 0 0 1 1 3 1 0 0 1 1 19
0 0 1 0 0 4 1 0 1 0 0 20
0 0 1 0 1 5 1 0 1 0 1 21
0 0 1 1 0 6 1 0 1 1 0 22
0 0 1 1 1 7 1 0 1 1 1 23
0 1 0 0 0 8 1 1 0 0 0 24
0 1 0 0 1 9 1 1 0 0 1 25
0 1 0 1 0 10 1 1 0 1 0 26
0 1 0 1 1 11 1 1 0 1 1 27
0 1 1 0 0 12 1 1 1 0 0 28
0 1 1 0 1 13 1 1 1 0 1 29
0 1 1 1 0 14 1 1 1 1 0 30
0 1 1 1 1 15
A ‘1’ in the table corresponds to the left (on) position of the switch. Switch 1 (top) selects
the least significant bit. The lower three switches, which are normally set to the off posi-
tion, are used to select the 9814 operating modes as follows:
Switch 6 - IEEE talk (transmit) mode.
Switch 7 - IEEE listen (receive) mode.
Switch 8 - Dual Primary Addressing mode In this mode, the 9814 will respond to two
primary addresses differing only in the least significant bit. For example, if the unit ad-
dress selection switches are set for an address of 8, the unit will also respond to ad-
dress 9.
NOTE: The 9814 only looks at the address switch at power up.
IEEE Commands
Local lockout
The front LOCAL/REMOTE switch must be in the remote position for IEEE operation.
The 9814 will not respond to any IEEE commands when sent to local.
Interface clear command IFC
This command initiates a complete reset of the 9814, which is then unable to respond to
any further IEEE commands for 1 second.

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IEEE command format
IEEE commands are comprised of characters from the ASCII set. A series of commands
can be used to simulate the manual operation of the 9814.
The commands must be in one of the following formats:
1. A single uppercase character (A to Z).
2. Upper case character followed by a number.
3. A signed decimal number (8 digits maximum).
Commands may be sent individually or built into a string separated with a ‘slash charac-
ter’ (/). For the command string to execute it must be terminated with either a line feed
or carriage return character.
IEEE command execution
Before an IEEE command can be executed 4 conditions must be met.
1. The 9814 must be switched to ‘remote’ on the front panel.
2. IEEE cable and controller connected. The IEEE address and the talk/listen
switches set correctly on the rear panel switch.
3. The command must be a valid command (invalid commands are ignored).
4. The command must be followed by a valid terminator.
IEEE command list
D Transmit display to bus controller bus controller.
E1 to E4 Select 9814 action upon output error detection.
G1 or G2 Set/Cancel Group execute trigger response.
H Set output to full scale.
I Select serial poll operation.
K1 or K2 Enable/Disable Front panel controls.
L Set output to zero.
Pn Change output by ‘n’ percent.
R1 to R4 Select range from 10mV to 10 V
R1 - 10mV R2 - 100mV
R3 - 1V R4 - 10V
T1 or T2 Set terminator character appended to a transmission.
Z Take present output as Zero Offset.
/ Command separator.

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Description of commands
Single letter commands
Command D
It is important to understand the sequence of operation on the IEEE bus when a data
read-back command is executed. When the ‘D’ Command is sent it prepares the 9814 to
transmit (i.e. act as a talker). The controller program must then execute an ‘INPUT’
statement to actually initiate the data transfer. The data must be terminated with the cor-
rect character to complete the transfer.
Invalid terminating characters cause the IEEE bus to hang.
The terminator is controller dependent and the 9814 allows either CR or LF to be used,
as determined by the 9814 Command T1 or T2. Note that the T1 or T2 command
(terminating setting) must be done before the ‘D’ command is executed.
When the 9814 is in the over-range condition the front panel display shows 1….. but this
is not transmitted on read-back. The character string ‘OVERRNG’ is sent. In all other
cases the read-back is exactly as seen on the display.
EXAMPLE: ( HP BASIC )
10 REMOTE 708
20 OUTPUT 708;"T2" !SET TERMINATOR
30 OUTPUT 708;"D" !TRANSMIT DISPLAY
40 ENTER 708;A$ !READ RETURNED VALUE IN
50 PRINT A$ !PRINT IT
Command H
Sets output to full scale.
EXAMPLE: ( CBM BASIC )
10 OPEN 1,7 :REM OPEN 9814 ADDRESS 7
20 PRINT # 1,'H' :REM SET OUTPUT TO F. SCALE
30 END :REM END
Command I
Sets the 9814 to generate a serial poll request for service by the bus controller should
an ‘OP ERROR’ arise. ( Auto-cal units only )

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EXAMPLE ( HP BASIC )
10 REMOTE 708 !OPEN IEEE ADDRESS 8
20 OUTPUT 708 ; "I" !SET 9814 TO GENERATE SERIAL POLL REQUEST ON
!OUTPUT ERROR
30 OUTPUT 708 ; "E4/R4/2" !SET ERROR MODE, 10V RANGE WITH 2 VOLTS
!OUTPUT
40 ON INTR 7 GOSUB 100 !DEFINE ACTION ON SERIAL POLL
50 V1 = 0 @ X = 0
60 X = X + 1! !WAIT FOR ERROR LOOP
70 GOTO 60
1000! SUBROUTINE TO PRINT POLL RESPONSE
1010 STATUS ,1;A 1020 P=SPOLL (708)
1030 PRINT P !DISPLAY SERIAL POLL RESULT
1040 ENABLE INTR 7;8
1050 RETURN !RETURN TO WAIT LOOP
Command L
Sets the output to ‘zero’ on the present range.
Command Z
Takes the present output value as an offset. The display indicates zero with the top segment
of the display flashing. When a new output value is sent it will be added to the offset stored.
The offset is cleared by:
1. A new range command
2. Selecting a resistance output
3. Setting the offset to zero.
In autocal mode, indicated by a flashing ‘C’ on the display, the offset is stored in the non
volatile memory and is used as a calibration factor.
Letter and number command
E1 to E4 output error mode
Selects one of 4 possible error modes which determine the action taken by the 9814 on
detection of an output error.
E1: (default). Display OP ERROR and turns off output immediately on detection of an out-
put error, remains in this condition until reset by another command.
E2: Displays OP ERROR and turns off output immediately on detection of OP ERROR, will
automatically restore output and display if the error is removed.
E3: Waits for an error condition to last for 0.5 seconds before turning off output and displaying
OP ERROR.
E4. Waits for an error condition to last for 0.5 seconds before displaying OP ERROR and
leaves output ON.

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G1/G2 enable/disable group execute trigger
G1 - Enables Group Execute Trigger response.
G2 - Disables Group Execute Trigger response.
Group Execute Trigger (GET) is a command issued by the bus controller to make sev-
eral devices respond simultaneously. The devices having been previously told how to
respond when the GET command is received.
EXAMPLE (HP BASIC)
10 REMOTE 708 !OPEN IEEE ADDRESS 8
20 OUTPUT 708;”G1” !SET 9814 TO RESPOND TO GET
30 OUTPUT 708;”R2” !COMMAND TO EXECUTE
40 TRIGGER 708 !EXECUTE COMMAND
50 OUTPUT 708;”G2” !COMMAND TO EXECUTE
60 TRIGGER 708 !EXECUTE COMMAND TO EXIT GET MODE
K1/K2 enable/disable front panel control
K1 - Set the 9814 to respond to front panel control
K2 - Disables front panel controls
P (n) set percentage deviation
Set deviation on present output in range +9.999 and –9.999.
EXAMPLE (CBM BASIC)
10 PRINT #1,”P3.456” REM SET output 3.456% high
20 PRINT #1,”P-0.02” REM SET output 0.02% low
R1 to R4 range setting commands
Selects a voltage range from IEEE command table.
COMMAND RANGE PROGRAM
SELECTED IN
R1 10mV mVolts
R2 100Mv mVolts
R3 1V Volts
R4 10V Volts
RA: Automatically selects the range for the output required. Default : R1
T1/T2 select transmission terminator
Sets the last character appended to a transmission from the 9814

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T1 (default) : carriage return
T2 : line feed.
Setting an output value
Transmit the voltage or current required as an ASCII string.
EXAMPLES (HP BASIC) on the 1 volt range (R3)
OUTPUT 708;2-0.3765” !SET OUTPUT TO –0.3765 VOLTS
OUTPUT 708;”1.9” !SETS OUTPUT TO OVER-RANGE DISPLAY SHOWS
! 1….., OUTPUT SET TO APPROX 1.3 VOLTS.
OUTPUT 708;”0.0000007” !SETS OUTPUT TO ZERO, TO MANY DECIMAL
PLACES
Notes:
1. The 7th digit is always rounded to 0 or 5.
2. The output limit of any range is 1250000

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Section 6 - Fault Diagnosis
Introduction
This section gives details of some possible problems, and how to correct them.
Spares parts are available from Time Electronics and are listed in Section 9. If
the fault is not listed or if parts required are not listed, please enquire quoting type
and serial number, and giving details of the fault where possible.
Fault check list
1) If the 9814 is completely dead with no front panel lights, check the following:
a) Mains supply.
b) Mains fuse blown in plug.
c) Mains fuse blown in combination appliance inlet.
d) Internal fuses blown (see fuse replacement).
2) If unit responds to manual control but not to IEEE control and the data light
does not flash, check the following:
a) Defective IEEE cable.
b) 9814 incorrectly addressed.
c) Incorrect terminating characters.
d) Processor board not correctly plugged in.
3) If unit responds to manual control but not to IEEE control and the data light
flashes, the probable fault is an incorrect command.
4) Unit powers up but not working correctly.
a) Run Self Test. See table 4.3 for error codes.
5) Unit displays ERROR 6.
a) Cal RAM corrupted.
6) Unit occasionally resets to power on (10mV range) condition and makes a
short bleep.
a) Mains interference is causing the microprocessor to stop, tripping the
watchdog circuitry to give an automatic restart. Additional mains filter-
ing required.

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Fuse replacement
Three types of fuse are used in the 9814
1) 2 AMP 20mm quick blow - 5V supply
2) 2 AMP 20mm anti surge - Mains input
3) 2.5 AMP 20mm anti surge - 18V supply
Replacement fuses are available from Time Electronics and R.S. Components. See
SECTION 9 (Spare Parts) for order details.
Fuse location and replacement procedure
1) The mains fuse:- This fuse is located in the mains inlet filter. To replace, discon-
nect equipment from mains and lever down hinged cover to reveal fuse holders.
2) 5V supply:- The 5V supply fuse is mounted on the left hand printed circuit board
of the power unit.
3) +/- 18V fuses:- These fuses are mounted on the right hand printed circuit board
of the power unit.
Main Frame
The 9814 is constructed on a 19 inch Euro-card frame. Cards and modules plug into
the frame from the rear of the unit.
All modules and printed circuit boards connect to the 64-way data bus via a DIN
41612 type connector.
The front panel is removed by unscrewing the four captive screws at each corner.
Then lift away from the frame.
Power Module Replacement
To remove the power unit module which is located on the right hand side of the
frame viewed from the rear, first unscrew the four captive screws in the corners of
the power unit rear panel. The power unit can then be pushed out of the rear of the
frame. DO NOT PULL ON THE MAINS LEAD.
Replacement is in the reverse order.
Replacement of IEEE and Processor Boards
The IEEE and processor boards are located behind the IEEE rear panel. Remove
the panel by unscrewing the four captive screws at each of its corners.