Time Electronics 5075 Use and care manual

Time Electronics Ltd
BOTANY INDUSTRIAL ESTATE
TONBRIDGE, KENT, TN9 1RH, UK
Tel: [phone] Fax: [phone]
Email: [e-mail]
Website: www.TimeElectronics.co.uk
5075
Precision
Digital Multimeter
Calibration Manual
V17 16/11/06

5075 Calibration Manual Page 2
Contents
Page
1. General Calibration Information 4
1.1 List of required equipment for calibration 4
1.2 Before and after calibration 4
1.3 Calibration factors 5
1.4 Calibration Precautions 5
Calibration leads and connections 5 - 6
Othererrors 6
Safety 7
2. Calibration Procedure 7
2.1 Calibration key 7
2.2 GPIB(IEEE) Address 7
2.3INTCAL 7
2.3 Menu options 8 - 9
2.4 5075 push buttons 9
2.5 Calibration Initialize 10
2.6 Calibration of DC Volt Ranges 11
Set Zero - Low DC Volt ranges 11
Set Full-Scale - Low DC Volt ranges 11 - 13
Set Zero - High DC Volt ranges 13
Set Full-Scale - High DC Volt ranges 13 - 14
Set Zero - Extra high DC Volt ranges 14
Set Full-Scale - Extra high DC Volt ranges 14 - 15
2.7 Calibration of DC Current Ranges 16
Set Zero - DC Current ranges 16 - 17
Set Full-Scale - DC Current ranges to 1 amp 17 - 19
Set Full-Scale - DC high Current ranges 20
2.8 Calibration of AC Voltage Ranges 21
Set Full Scale - AC Volt range 21 - 22
Set Full Scale - Extra high AC Volt range 22
2.9 Calibration of AC Current Ranges 23
Set Full-Scale - Low AC Current ranges 60Hz 23
Set Full-Scale - High AC Current ranges 60Hz 24
3.0 Calibration of Capacitance 25
Set ‘Zero’ Capacitance 25
Set Full Scale Capacitance 25 - 26
3.1 Calibration of Resistance 27
Set Zero calibration factors 27 - 29
Set Full Scale Resistance 30 - 33

5075 Calibration Manual Page 3
Contents continued
Page
3.2 Calibration Data Entry 34
Certification Number entry 34
Calibration Date entry 34
Calibration Temperature entry 35
Calibration Due Date entry 35
Calibration Period entry 35
Sample Certificate of Calibration 36 - 40

5075 Calibration Manual Page 4
1. General Calibration Information
1.1 Calibration equipment required :
• Precision multifunction calibrator e.g. Time 5025
• Precision multimeter e.g. HP 3458A
• Precision multi-resistor standard box e.g. Time 7003 (1to 10M)
• 10m4 wire standard
• 100m4wire standard
• 100M2wire standard
• 1000M2 wire standard
• 30nF capacitance standard
• 300nF capacitance standard
• 3µF capacitance standard
• 30µF capacitance standard
• 300µF capacitance standard
• Precision low noise DC current source 3µA, 30µA, 100µA e.g. Time 1024
• Screened low thermal e.m.f. 4 wire test leads
• Screened low thermal e.m.f. 2 wire test leads
• High current (32amp) test leads
• BNC high voltage, 10kV test leads
• Supplied calibration key
• Technical manual
Switch on the 5075, the multifunction calibrator and the low noise DC current source
and leave them on to warm up for at least 2 hours prior to calibration, ambient room
temperature for calibration should be 22oC ± 2oC
1.2 Before and After calibration
It is advisable that a complete set of calibration results are taken before the re-
calibration is started in ordinary mode i.e. IEEE address not 0,16 or 32. This process
is know as the ‘BEFORE’. It is important because it verifies that the 5075 is
operating correctly on all ranges and indicates which ranges will need adjustment. If
any of the ranges are a long way out it indicates that the 5075 might be faulty.
Please refer to the Time Electronics example calibration certificate at the end of this
document, for details of the allowed errors of the calibration adjustment points.
Please note that some of the allowed errors shown may be slightly more precise
than the published specification.

5075 Calibration Manual Page 5
1.3 Calibration Factors
The calibration factors are numerical values stored in internal non-volatile memory.
When calibration is complete, it is good practice to keep a written record of all the
calibration factors for future reference. Should the 5075 lose its internal memory or the
calibration factors become corrupted for any reason, it will be possible to re-enter them
without having to go to length of a full re-calibration. It should be noted that the zero
calibration factors are not available for inspection and therefore can not be recorded.
However, it is not difficult to re-calibrate each range zero with a shorting link (or open
circuit for current and capacitance ranges).
1.4 Calibration Precautions
Before calibrating the 5075 instrument, please read though this manual and ensure that
you learn all of the following points :
Range specific information
Normally the 5075 is not adjusted for calibration within the following functions,
Volts (AC+DC) mixed signal
Current (AC+DC) mixed signal
PRT option
Frequency
Ohms compensated
Hence on these ranges during calibration procedure of the 5075 they should be tested
and recorded on the calibration certificate, however there is no adjustment. If a 5075
unit seems to be out of specification on these ranges then contact Time Electronics for
advice.
Additionally it is acceptable for the 3kV and 10kV ranges to be calibrated only with a
precision 1kV voltage source.
All AC voltage ranges are to be calibrated at 200Hz
All AC current ranges are to be calibrated at 60Hz
Calibration leads and connections
Thermal EMF’s can affect calibration. The terminals of the 5075 are made from linear
crystal oxygen free copper to minimize this effect. If however nickel plated brass plugs
are used, thermally generated emfs will be generated and errors will occur. Leads and
connectors that exhibit low self thermal emf effect should be used especially on voltage
ranges below 10V.
To further reduce noise and AC capacitive/inductive coupling, the leads should be kept
as short as practically possible. The use of short screened leads is recommended for all
low AC voltage and current calibrations.

5075 Calibration Manual Page 6
Calibration leads and connections (continued)
For calibration of the 3kV and 10kV ranges, use the BNC input connector. The
shield of the BNC cable is earth, as with the supplied HV cable a short flying lead
connects the shield to the negative sense input socket.
Resistance calibration up to the 300krange must be calibrated using a 4-wire type
source, ranges above this should be calibrated using a 2-wire type resistance.
When calibrating resistance ranges of 1Mand above, screened (shielded) leads
must be used to reduce noise. The shield should be connected to the yellow guard
terminal. If difficalties are being experianced and readings are unstable or not
repeatable, please read the ‘Measurement Techniques’ chapter in the 5075
technical manual carefully.
Other errors
When switching from a range greater than 10V down to mV ranges, additional time
must be allowed for zero settling, around 90 seconds.
Whilst calibrating the 10 Amp and 30 Amp ranges, do not leave the current on for
longer then required to take a reading as self heating via the internal current shunts
will cause thermal drift.
Avoid open circuiting the input terminals on the 3 Ohm or the 30 Ohm resistance
ranges since the zero settling effect will cause errors.
Safety
EXTREME CAUTION must be exercised when calibrating very high voltages or high
currents. When working with high voltage do not work alone and do not depend
upon the insulation of the cables for protection. When in doubt please refer to the
5075 technical manual for information on connection.

5075 Calibration Manual Page 7
2. Calibration Procedure
IMPORTANT NOTE: If the 5075 has corrupted Cal Factors (Cal Factor Error 002) it is
necessary to clear the Cal factors before re-calibration as follows.
1) Switch off 5075
2) Select address 32 on GPIB address dip switch (all switches ON - down)
3) Insert Cal Key
4) Switch on 5075
5) You will see the 5075 run through a self test and when finished show ‘PASS’
6) Switch off the 5075
The 5075 is now ready to be re-calibrated as described below.
2.1 Calibration key
The 5075 has a separate calibration key (referred to as Cal Key). It is plugged in a
rear panel socket (near the GPIB switch). The calibration factors in the 5075 can not
be modified or deleted without this key inserted. When the cal key is inserted a small
‘c’ appears on the display next to the units - the cal factors can now be changed.
2.2 GPIB(IEEE) Address
The GPIB address is changed via the dip switches at the back.
The following address are used for special purposes,
2.3 INTCAL
If INTCAL appears on the screen while calibrating the 5075, wait for it to finish, and
then repeat only the calibration of the range currently selected.
INTCAL is an internally generated self-calibration function which automatically occurs
approximately every 15 minutes. It does not affect the external calibration.
0 and 16 Set 5075 in to calibration mode, enhanced menu access
32 Initialize a full reset and internal test for all functions of the 5075. If
cal key is in, this function will also clear all cal factors stored in the
5075’s memory and it will have to be re-calibrated.

5075 Calibration Manual Page 8
2.3 Menu options
The 5075 menu is entered by using the ‘MENU’ key, it can be navigated through the
options by using the ’UP’ and ‘DOWN’ arrow keys, and selection is then confirmed
using the ‘USER FUNC’ key, also referred to as the ‘E’ key.
When the 5075’s IEEE address is set to ether 0 or 16, the menu has expanded
selections to include the calibrate mode options. Even though the menu will display
options to adjust the calibration factors, they cannot be selected unless the cal key
is in place on the rear of the machine. Step through the options and check they are
correct before commencing calibration.

5075 Calibration Manual Page 9
2.3 Menu options (continued)
Please note that the Cal key does not have to be inserted to view all
options, but it MUST be inserted to edit or execute functions marked
with ‘*’
2.4 5075 push buttons
In this manual the 5075 push buttons will be referred to as the legends as printed on
them, e.g ‘MENU’. However throughout this document we will use the shorthand for
the ‘User Func’ key which is written as ‘E’ this is used to select items from the menu.
A. Self Test & Reset Run this to internally test all of the 5075 functions
B. IEEE Address Indicates the setting of the rear panel switches
C. Serial Number* Display and change the 7075 serial number
D. Certificate Number* Previous cert. Number. To be updated after calibration
E. Calibration Date* Previous cal date. To be updated after calibration
F. Calibration Due* Previous cal due date. If run out, set before cal run
G. Calibration Temperature* Ambient room temperature at time of calibration
H. Calibration Period* Normally 52 weeks, can be set from 1 to 999 weeks
I. Key press beep on/off Select as required
J. Continuity beep on/off Select as required
K. Sample beep on/off Select as required. Turn OFF for calibration run
L. Analogue filter on/off Select as required. Turn ON for calibration
M. Countdown on/off Select as required. Used with the dynamic I/O filter
N. Scanner display on/off Select if scanner fitted. OFF for calibration
O. Auto Dynamic filter on/off Select as required. Turn ON for calibration
P. PRT Temperature Select as required. Turn OFF for calibration
Q. Calibration due warning Select as required. Indicates when overdue for calibration
R. Store options* Stores options/front panel settings as power up defaults
S. Date Shows current date
T. Time Shows current time
U. Internal Temperature Shows 5075 internal temperature for reference only
V. Self Calibrate Initiates a ‘INTCAL’. Always do this before a calibration run
W. Clear Cal Factors on/off* Clears the cal factors for the selected range. LEAVE OFF
X. Display Cal Factors on/off Shows the cal factors for the current range. Replaces range info.
Y. Adjust to Value* Used to set the cal factor for non full scale inputs
Z. Calibrate to full scale* Used to set the cal factor with full scale input

5075 Calibration Manual Page 10
2.5 Calibration Initialize
• Make a note of original IEEE switch setting.
• Change IEEE address of the 5075 to 16 ( refer to page 39 of 5075 tech
manual) to enter calibration mode.
• Power-up the 5075 and go into the menu by pressing ‘Menu’ then select the
option “Self Test & Reset” to check if the 5075 functions are operating
correctly.
• Power-up all calibration equipment and allow 2 hours for all equipment
including the 5075 to warm up and stabilize.
• Press the ‘Filter’ button repeatedly until a filter time of 1 second is selected.
• Press the ‘N Digits’ button repeatedly until a 6 digit display is selected.
• Press the ‘Auto’ button to turn OFF auto range.
• Enter the options menu by pressing ‘Menu’ and change the following options :
Sample beep on/off Set to OFF
Analogue filter on/off Set to ON
Scanner display on/off` Set to OFF
Auto dynamic filter on/off Set to ON
PRT Temperature on/off Set to OFF
• Enter the options menu by pressing ‘Menu’ and using the ‘Ï’ and ‘Ð’ arrow
keys, select “Self Calibration” and confirm by pressing the ‘E’ key. This calls a
INTCAL and sets the internal A-to-D converter before calibration.