Time Electronics 1048 User manual

User Manual
1048
Voltage / Current / Loop Calibrator
Version 1.3
12-23
Time Electronics Ltd
Unit 5, TON Business Park, 2-8 Morley Road,
Tonbridge, Kent, TN9 1RA, United Kingdom.
T: [phone] | F: [phone]
[e-mail] | www.timeelectronics.com

© 2023 Time Electronics Ltd.
All rights reserved.
Nothing from this manual may be multiplied, or made public in any form or manner, either
electronically or hard copy, without prior written consent from Time Electronics Ltd.
This also applies to any schematics, drawings and diagrams contained herein.
This manual provides operating and safety instructions for the Time Electronics product.
To ensure correct operation and safety, please follow the instructions in this manual.
Time Electronics reserves the right to change the contents, specifications and other
information contained in this manual without notice.

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Contents
1Introduction....................................................................................................................................2
1.1 Description.............................................................................................................................................2
1.2 Applications ...........................................................................................................................................3
1.3 Features ................................................................................................................................................ 4
1.4 Ordering Information and Options .........................................................................................................4
2Specifications ................................................................................................................................5
2.1 Technical Specifications ........................................................................................................................5
2.2 Settings and General Specifications......................................................................................................6
3Controls and Operating Modes ....................................................................................................7
3.1 Front Panel Controls.............................................................................................................................. 7
3.2 Operating Modes ................................................................................................................................... 8
4Operating Notes.............................................................................................................................9
4.1 Power ....................................................................................................................................................9
4.2 Operating Precautions........................................................................................................................... 9
4.3 Resolution Adjustment.........................................................................................................................10
4.4 Polarity Setting .................................................................................................................................... 11
5Normal Operation ........................................................................................................................12
5.1 Voltage Measurement .........................................................................................................................12
5.2 Current Measurement (external loop power) .......................................................................................13
5.3 Power and Calibrate - transmitters/sensors.........................................................................................14
5.4 Voltage Source .................................................................................................................................... 15
5.5 Current Source .................................................................................................................................... 16
5.1 Sink - transmitter simulator (TX SIM)...................................................................................................17
6Step and Ramp Operation...........................................................................................................18
6.1 Step Mode ........................................................................................................................................... 19
6.2 Ramp Mode .........................................................................................................................................21
7Maintenance and Calibration......................................................................................................22
7.1 Power Supplies.................................................................................................................................... 22
7.2 Disassembling the unit ........................................................................................................................23
7.3 Trimmer Locations............................................................................................................................... 25
7.4 Re-Calibration...................................................................................................................................... 26
7.5 Reassembling the Unit ........................................................................................................................28
8Warranty and Servicing............................................................................................................... 29

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1Introduction
1.1 Description
A portable instrument that operates as a current and voltage source and a multi-purpose
loop calibrator. High performance and simple operation make it suitable for R&D, service,
process control engineers, and calibration technicians. As a versatile handheld calibrator,
the source and measure capabilities with 0.02 % accuracy mean the 1048 is a compact
solution for most simulation and test applications.
The large, easy to read 4.5-digit LCD display shows the actual output, even when the
connected load exceeds the specifications. This important feature eliminates the risk of large
errors when connecting to unknown loads. The display also indicates if the battery becomes
critically low.
In the source mode, voltage up to 22 V and current up to 22 mA may be generated in three
ranges. When in current source mode the 1048 has a high 24 V compliance voltage which is
ideal for powering process loops. In the measurement mode, the range and function can be
easily selected, with the measured input accurately shown on the display.
The step and ramp functions are simple operation, with no key press menus to learn, just
switches and buttons. A multi-turn potentiometer controls the output, with up/down
incrementing buttons for fine control. The output can be reversed (+/-) and zeroed at the flick
of a switch. The automatic ramp function enables the user to choose either 5, 11, or 21 point
calibration. Manual operation can be quickly restored by a single push of a button.
The 1048 is housed in a pocket-sized ABS case, with carry case supplied as standard.
Connections are by standard 4 mm plugs or by clamping the wires under the terminals. A
single 9 V battery powers the unit or an external 12 V DC power supply may be used which
disconnects the internal battery. The unit is constructed in a rugged pocket size hard ABS
case and supplied with leatherette carrying pouch. Leads can be stored in the pouch.

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1.2 Applications
Common use of the 1048 is to simulate a transducer or measure the current flow in a
transducer loop. The 1048 can be used to check a 4 to 20 mA system in either source or
measure modes of operation, with the 24 V compliance voltage powering the loop when
current source mode is selected.
In the source mode, the 1048 may be used to calibrate meters, thermocouple indicators,
data loggers, for signal injection, semiconductor characterization, or as a backing off source.
In the measure mode, the 1048 may be used in the same way as a digital multimeter,
checking DC voltages and current over 3 ranges with excellent resolution and accuracy.

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1.3 Features
•Measure voltage and current
•3 source ranges: 0 to 22 mA and 0 to 22 V
•3 measure ranges: 0 to 70 mA and 0 to 50 V
•Accuracy 0.02 %
•Transmitter simulator/sink loop control
•Output steps and ramps
•Coarse and fine adjustment
•20 hours typical battery life
•Optional mains power supply
(230 V and 110 V available)
•Supplied with carry case
1.4 Ordering Information and Options
Order Code Description
1048 Voltage/Current/Loop Calibrator
7643 Mains power supply (230 V)
7652 Mains power supply (110 V)
C176 Traceable Calibration Certificate (Factory)
C138 Accredited Calibration Certificate (ISO 17025)

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2Specifications
2.1 Technical Specifications
Voltage source
Range Resolution Accuracy
Output
current Temp coefficient
0 to 220 mV 10 μV, 100 μV above 0.2 V 0.05 % of FS
20 mA ± 6 ppm/°C0 to 2.2 V 100 μV, 1 mV above 2 V 0.02 % of FS
0 to 22 V 1 mV, 10m V above 20 V 0.02 % of FS
Voltage measure
Range Resolution Accuracy Measure load Temp coefficient
0 to 220 mV 10 μV, 100 μV above 0.2 V 0.05 % of FS ± 1 digit 1 MΩ
± 3 ppm/°C
0 to 2.2 V 100 μV, 1 mV above 2 V 0.02 % of FS ± 1 digit 1 MΩ
0 to 22 V 1 mV, 10 mV above 20 V 0.02 % of FS ± 1 digit 10 MΩ
Current source
Range Resolution Accuracy Output voltage Temp coefficient
0 to 220 μA 10 nA, 0.1 μA above 200 mA 0.05 % of FS
24 V Max ± 12 ppm/°C0 to 2.2 mA 0.1 μA, 1 μA above 2 mA 0.02 % of FS
0 to 22 mA 1 μA, 10 μA above 20 mA 0.02 % of FS
Current measure
Range Resolution Accuracy Input load Temp coefficient
0 to 220 μA 10 nA, 0.1 μA above 200 mA 0.05 % of FS ± 1 digit 1 kΩ
± 8 ppm/°C
0 to 2.2 mA 0.1 μA, 1 μA above 2 mA 0.02 % of FS ± 1 digit 110 Ω
0 to 22 mA 1 μA, 10 μA above 20 mA 0.02 % of FS ± 1 digit 16 Ω

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2.2 Settings and General Specifications
Sink (Tx Simulation).............2 wire transmitter simulation: External excitation voltage,
3 V min, 50 V max.
The current sink levels are adjustable, with accuracies as per
the 3 source ranges shown on previous page.
Note: Accuracies in all measure modes are ± 1 digit.
Output steps..........................5 fixed 4 mA steps for current output 4, 8, 12, 16 and 20 mA.
11 fixed 1 V steps for voltage output 0,1,2. 10 V.
21 fixed steps 1 V/1 mA for V and I output 0,1,2. 20.
Stepping can be done manually or automatically (Autostep).
Stepping speed is adjustable (1 - 9 sec/step). Dwell time (top
and bottom) is one step period. In step mode the accuracy is
limited to 0.05 % of span ± 1 digit.
Output adjustment ................A ten turn potentiometer for quick setting,
with fine adjust using up/down increment buttons.
Connections ..........................Made by 4 mm connectors or clamped using the wire
compression feature.
Power .....................................PP3 size, 9 V battery.
Approximately 20 hours of life depending on the current sourced.
Alternatively, an optional 12 V power supply can be plugged into
the 2.5 mm socket on the top of the unit.
Protection ..............................The 1048 can withstand open circuits,
short circuits and reverse polarity up to 25 V. Additional
protection is by an internal fuse.
Operating temperature .........-10 to 50 °C.
Storage temperature.............-30 to 70 °C.
Operating humidity ...............0 to 90 % non-condensing at 25 °C.
Dimensions............................H 142 x W 78 x D 50 mm.
Weight ....................................0.30 kg.
Optional extras......................230 V or 110 V mains power supplies.
Calibration certificates:
Traceable (Factory) and Accredited (ISO 17025).
Country of origin...................UK.

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3Controls and Operating Modes
3.1 Front Panel Controls
Input/Output Terminals
Safety terminals for 4 mm shrouded plugs,
standard plugs, bare wires, spade terminals.
Output switch
For normal (NORM),
zero (OFF), reverse (REV).
Also used to restore high
resolution display.
Coarse Adjust Dial
10-turn control for coarse output adjustment.
Also used for setting secs in Step mode.
OFF/V/mA Switch
3-position switch to select
on/off (OFF), volts (V),
or current (mA).
Range Switch
3-position switch to select
V and mA ranges:
22 / 2.2 / .22.
Function Switch
3-position switch for
source (SRC),
measure (MEAS),
transmitter simulation
(TX SIM).
Increment Button (INC)
Push button for fine
increasing of the output.
Also used to select an
operating mode (see p8).
Decrement Button (DEC)
Push button for fine
decreasing of the output.
Also used to select an
operating mode (see p8).
Display
4.5 Digit LCD display of
output and measure.

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3.2 Operating Modes
The 1048 has 3 operating modes; Normal, Step, and Ramp.
3.2.1 NORMAL Operating Mode
Provides manual operation of the standard measure and source functions for both voltage
and current. A transmitter simulation/sink (TX SIM) function is also included for loop test and
calibration. The internal power supply can also be used to provide the drive voltage to
passive process control transmitters and sensors. This allows them to be calibrated without
the need for the loop power to be connected.
3.2.2 STEP Operating Mode
Provides output steps of fixed value. Three options are available:
A. 5-point calibration: 4, 8 ,12, 16, 20 mA.
B. 11-point calibration: 1,2,3,4,5,6,7,8,9,10 V.
C. 21-point calibration: 1,2,3,4,5…18,19,20 mA or V.
The stepping between the calibration points can be done manually or can be set to proceed
automatically at an adjustable rate (see Section 5).
3.2.3 RAMP Operating Mode
Provides a continuous ramp up/down with dwell periods at the top and bottom. Both voltage
and current are available for ramping (see Section 5).
3.2.4 Changing/Selecting the Operating Mode
The default mode at power up is NORMAL.
The above modes are selected by simultaneously pressing the INC and DEC buttons.
Every time they are pressed the next mode will be selected.
This is followed by STEP, which is indicated by the ‘CONTINUITY’ legend appearing in the
top right section of the display.
The final mode is RAMP, which is indicated by the ‘CONTINUITY’ legend flashing.

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4Operating Notes
4.1 Power
The unit is powered by a PP3 (Alkaline) battery that lasts approximately 15 hours of normal
operation. Continuous operation on current will shorten the battery life. The unit will indicate
‘Low Battery’ when the battery needs changing. A short period of operation is possible
when ‘Low Battery’ is showing but no more than a few mA will be available at the output.
See Maintenance Section for battery replacement instructions.
The unit can also be operated from an external 12 V DC (100 mA) mains power supply unit.
This is available as an optional extra. Connection is via the small jack plug socket on the
terminal end of the unit.
4.1.1 Automatic power down disable
If the unit is not operated for 15 minutes, it will automatically power down to conserve the
battery life. This feature can be disabled by pressing the INC button when switching on the
unit. It should be noted that the operation is indicated by flashing the decimal point at the
switch on time.
Hold when switching on to disable
auto power down feature.
4.2 Operating Precautions
4.2.1 Display
The LCD display should not be exposed to strong sunlight for prolonged periods.
It is recommended to store the unit inside the supplied carry case when not in use.
4.2.2 Usage and Storage Conditions
•Operating temperature: –10 to 50 °C.
•Storage temperature: –30 to 70 °C.
•Operating humidity: 0 to 90 % non-condensing at 25 °C.

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4.3 Resolution Adjustment
4.3.1 Resolution high/low
The unit has a unique method of changing the display resolution when values greater than the
conventional 19999 (4.5 digit) display are used. This feature allows the units ranges to be
extended by 10% above the commonly used 0.2/2.0/20 full scales. Calibration of values just
above these figures is now possible. This will be found particularly useful with 4 - 20mA
transducers where they are slightly over scale but are still within specification.
For both measure and source functions, high resolution (4.5 digit, e.g. 1.9999) will apply for
all values below:
•0.20 on the 0.22 range
•2.0 on the 2.2 range
•20 on the 22 range
All values above those above will be displayed to 3.5 digit resolution e.g. 21.05.
The change-over from high to low resolution is automatic. However, if the value increases and
the resolution changes from high to low, it will not return to high resolution until the value is
reduced to:
•0.1 on the 0.22 range
•1.0 on the 2.2 range
•10 on the 22 range
To force the display back into high resolution the output polarity switch should be moved
from Hi to Lo to Hi.
There is a marking on the front panel below the switch to indicate this:

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4.4 Polarity Setting
4.4.1 Output Polarity Switch
It is important for the user to understand the operation of the
output polarity switch.
The switch has three positions, NORM / OFF / REV, and its
function depends on the operating mode being used.
4.4.1.1 Measure function (V & mA)
In the NORM position the unit will measure inputs connected in the same polarity as the
terminals i.e. red is positive and black negative.
The OFF (centre) position, when measuring voltage, disconnects the signal internally and
leaves the input terminals still providing 1 M Ωinput resistance. The display should read
zero but occasionally the last digit may show ‘1’, this is normal and is within the specification.
The OFF position, when measuring current, disconnects the signal internally and leaves the
input terminals still providing the current shunt input resistance. The display should read zero
but occasionally the last digit may show ‘1’, this is normal and is within the specification.
The REV position is not used since the unit’s measuring capability is bi-polar i.e. it can
accept both +ve and –ve input signals. The –ve inputs are displayed with a ‘-’ sign in front of
the value.
4.4.1.2 Source function (V & mA)
The NORM position outputs signals in the polarity indicated by the terminals.
The REV position reverses the polarity.
When outputting voltage or current, the OFF position disconnects the output signal and
places an open circuit on the output terminals. The display will read zero.
NOTE: When the switch is in the REV position it should be noted that the display does not
place a – (minus) annunciator before the value.
4.4.1.3 TX SIM function
The switch is not used for this function and has no effect at all.
4.4.1.4 STEP and RAMP modes
In both these modes the function switch is in source (SRC) position and the NORM/OFF/REV
switch performs in the same way as in the NORMAL operating mode.

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5Normal Operation
5.1 Voltage Measurement
The unit measures dc voltage in three selectable ranges, 0 to 0.22 V (displayed in mV),
0 to 2.2 V and 0 to 22 V (plus over-range to 50 V).
SPECIAL NOTE: Although the top range is nominally 22 V it can be safely used to measure voltages up to 50 V.
•Set Function switch to MEAS
•Set OFF/V/I switch to V
•Set Range switch to the desired range (22 / 2.2 / .2)
•Set Output switch to NORM
•Connect the unit to the signal source observing correct polarity, the voltage will be
displayed with 3.5 or 4.5 resolution (see section 4.3 for resolution notes).
Measure Mode
V set
NORM set
Range set
MEAS set

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5.2 Current Measurement (external loop power)
The unit measures current in three selectable ranges, 0 to 0.22 mA (displayed in μA),
0 to 2.2 mA and 0 to 22 mA (plus over-range to 70 mA).
SPECIAL NOTE: Although the top range is nominally 22 mA, it can be safely used to measure current to 70 mA.
•Set Function switch to MEAS
•Set OFF/V/I switch to mA
•Set Range switch to the desired range (22 / 2.2 / .2)
•Set Output switch to NORM
•Connect the unit to the signal source observing correct polarity, the current will be
displayed with 3.5 or 4.5 resolution (see section 4.3 for resolution notes).
Measure Mode

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5.3 Power and Calibrate - transmitters/sensors
If the external loop power supply is not available, it is possible to use the unit’s internal
22 V supply to power the loop. Set up the unit as described below.
•Set Function switch to SRC
•Set the multi-turn output control dial fully clockwise.
•Set OFF/V/mA Switch to mA
•Set Range switch to the desired range (22 / 2.2 / .2)
•Set Output switch to NORM
•Connect the unit to the sensor or transmitter observing the correct polarity.
The current drawn is displayed.
Measure and Power Mode

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5.4 Voltage Source
The unit outputs voltage from 0 to 22 V in three ranges:
0 to 0.22 V (displayed in mV)
0 to 2.2 V
0 to 22 V
To source voltage follow the steps below:
•Set Function switch to SRC
•Set OFF/V/I switch to V
•Set Range switch to the desired range (22 / 2.2 / .2)
•Set Output switch to NORM
•Set multi-turn output control dial to minimum (anticlockwise)
•Connect the unit to the process instrument observing correct polarity and adjust the
multi-turn output control dial for coarse control and INC / DEC buttons for fine control.
Source Mode
V set
NORM set
Range set
SRC set
Use dial for coarse
adjust, buttons for
fine adjust

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5.5 Current Source
The unit outputs current from 0 to 22 mA in three ranges:
0 to 0.22 mA (displayed in μA)
0 to 2.2 A
0 to 22 A
•Set Function switch to SRC
•Set OFF/V/I switch to mA
•Set Range switch to the desired range (22 / 2.2 / .2)
•Set Output switch to NORM
•Set multi-turn output control dial to minimum (anticlockwise)
•Connect the unit to the process instrument observing correct polarity and adjust the
multi-turn output control dial for coarse control and INC / DEC buttons for fine control.
Source Mode

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5.1 Sink - transmitter simulator (TX SIM)
In the Sink function, the unit simulates a process field transmitter as part of a loop testing
and calibration operation. The unit takes its excitation power from the loop and acts as a
variable resistance to adjust the loop current to the value shown on the unit’s display.
The excitation voltage must be in the range 3 to 50 V DC.
The NORM/OFF/REV switch is not functional in the SINK mode.
•Set function switch to TX SIM
•Set OFF/V/mA switch to mA
•Set range switch to the 22 position at the top
•Set output switch to NORM
•Set multi-turn output control dial to minimum (anticlockwise)
•Connect the unit in the loop observing correct polarity. Set the current in the loop by
adjusting the multi-turn control (coarse) and the INC/DEC buttons (fine).
Sink Mode (transmitter simulator)

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6Step and Ramp Operation
These modes are designed to automate and speed up the process of testing and calibration.
The STEP mode allows simplified calibration. It provides output steps of fixed value.
Three options are available:
A. 5-point calibration: 4, 8 ,12, 16, 20 mA.
B. 11-point calibration: 1,2,3,4,5,6,7,8,9,10 V.
C. 21-point calibration: 1,2,3,4,5…18,19,20 mA or V.
Aand Bare the default options, ie 4-20 mA for current source, 0-10 V for voltage source.
The Coption is obtained by powering up the unit while pressing the DEC button.
Hold on switch on for 21 point step option
The RAMP mode provides a continuous ramp up/down with dwell periods at the top and
bottom. Both voltage and current are available for ramping and the ramp limits can be
selected as shown above i.e. for 5, 11 or 21 point calibrations.
Selecting the Operating Mode
The above modes are selected by simultaneously pressing the INC and DEC buttons.
Every time they are pressed the next mode will be selected.
The default mode at power up is NORMAL.
This is followed by STEP, which is indicated by the ‘CONTINUITY’ legend appearing in the
top right section of the display.
The final mode is RAMP, which is indicated by the ‘CONTINUITY’ legend flashing.