Time Electronics 1048 Operating Manual

Time Electronics

1048 Current / Voltage / Loop Calibrator

Technical Manual

V1.2 30/12/10 Time Electronics Ltd

Botany Industrial Estate, Tonbridge, Kent, TN9 1RH

Tel: +44(0)1732 355993 Fax: +44(0)1732 770312

Email: mail@timeelectronics.co.uk

Web Site: www.timeelectronics.com

1. Introduction .................................................................................................... 3

2. F ront panel controls and operating modes ................................................. 4

2.1. Operating Mode: NORMAL ............................................................................ 5

2.2. Operating Mode: STEP .................................................................................. 5

2.3. Operating Mode: RAMP ................................................................................. 5

3. Normal Operating Mode ................................................................................ 6

3.1.1. Resolution high/low ............................................................................................ 6

3.1.2. Output polarity switch ......................................................................................... 6

3.2. Measure – Voltage ......................................................................................... 7

3.3. Measure – Current ......................................................................................... 8

3.4. Power and calibrate - transmitters/sensors ................................................. 8

3.5. Source – Voltage............................................................................................ 9

3.6. Source – Current............................................................................................ 9

3.7. Sink - transmitter simulator (TX SIM) ..........................................................10

4. Additional Operating Modes ....................................................................... 11

4.1. STEP - Manual ...............................................................................................11

4.2. STEP – Automatic .........................................................................................12

4.3. RAMP .............................................................................................................12

5. Operating Precautions ................................................................................. 13

5.1. Display ...........................................................................................................13

5.2. Usage & Storage ...........................................................................................13

5.3. Automatic power down disable ...................................................................13

6. Power S upplies ............................................................................................ 14

6.1. Auto-power down .........................................................................................14

6.2. Battery Life ....................................................................................................14

6.3. Battery Replacement ....................................................................................14

6.4. Mains Power Supply Adapter .......................................................................14

6.5. Fuse Replacement ........................................................................................14

7. Maintenance ................................................................................................. 15

7.1. Recalibration .................................................................................................15

7.2. Dis-Assembling the Unit ..............................................................................16

7.3. Trimmer Locations .......................................................................................17

7.4. Measure Function Calibration ......................................................................18

7.5. Step Mode Calibration ..................................................................................19

7.6. Current Shunt Calibration ............................................................................19

7.7. Re-Assembling the Unit ...............................................................................20

7.8. Calibration Certificates.................................................................................20

7.9. Front Panel Keypad and Connections ........................................................20

8. S pecifications ............................................................................................... 21

9. Guarantee & S ervicing ................................................................................. 23

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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Source Mode

Receiving instrument

Measure Mode

Sensor

- +

Pow er Suppl

2 wire transducer/transmitter

_ P ower + Supply

Sink Mode (transmi tter simulator)

Controller

+ -

+ Sensor

Measure & Power Mode

2 wire transducer/transmitter

1. Introduction

The 1048 is a current, voltage, and loop calibrator that meets the needs of R&D labs and

process control engineers. It provides source and measure functions in three current and voltage ranges, plus a transmitter simulator/sink function. Accuracy is 0.02% of span and it has 4.5 digit (0.005% of span) resolution.

Output m odes include steps and ramps. No menus to learn, just switches and buttons. A

multi-turn potentiometer controls coarse output adjustment while increment/decrement buttons are provided for fine control. The source output can be reversed (+/ -) and zeroed at the flick of a switch. The front panel features a large easy-to-read 4.5 Digit LCD display that auto-ranges to allow the ranges to be extended by 10% above the normal 0.2/ 2.0/20 full scale. Manual reset of the ramp function is also provided for quick restore.

The unit is powered by a PP3 (Alkaline) battery that lasts approximately 15 hours.

Continuous operation in the current mode will shorten the battery life. The unit will indicate ‘Low Battery’ when the battery needs changing.

When used as a source the output can be zeroed and reversed to enable the calibration of

centre-zero type voltage or current instruments e.g. –10V to 0 to +10V.

If the unit is not operated for approximately 15 minutes, it will automatically power down to

conserve battery life. If required this feature can be disabled in the user set-up.

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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G. Range switch

2. Front panel controls and operating modes

A. Terminals

B. Display

C. OFF/V/mA switch

D. Decrement (DEC)

H. Increment (INC)

E. Multi-Turn

Output Control

I. Function switch

F. Output switch

A. Input/Output terminals B. 4.5 Digit LCD Display. C. 3 position switch for ON/OFF( OFF), Vol ts (V), Current (mA). D. Push button for fine decreasing (DEC) of the output. E. 10 turn control for coarse output adjustment F. 3 position switch, normal (NORM), zero (OFF), reverse (REV) output. Also used to

restore high resolution display. G. 3 position range switch (22, 2.2, 0.22). H. Push button for fine increasing (INC) of the output. Also used in conjunction with the

I. 3 posit ion function switch for source (SRC), measure (MEAS), and transmitter

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DEC button to select the modes of operation i.e. Normal, Step, and Ramp. When in

Step mode, it initiates automatic stepping. When in Ramp mode, it re-starts the ramp.

simulation (TX SIM).

The unit has three principal operating modes:

2.1. Operating Mode: NORMAL

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.

2.2. Operating Mode: STEP

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 mA or 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 (see Section 4.1), or

can be set to proceed automatically at an adjustable rate (see Section 4.2)

2.3. Operating Mode: RAMP

Provides a continuous ramp up/down with dwell periods at the top and bottom. Both voltage and current are available for ramping (see Section 4.3)

SELECTING THE OPERATING MODE: The above operating modes are selected by simultaneously pressing the INC and DEC buttons. Every time they are pressed the next mode will be selected. The 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

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3. Normal Operating Mode

3.1.1. 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:

• 0.1on 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 operated from Hi to Lo to Hi. There is a marking on the front panel below the switch to indicate this.

3.1.2. Output polarity switch

It is important for the user to understand the operation of the output polarity switch (‘F’ on the front panel diagram section 2.). The switch has three positions, NORM/OFF/REV, and its function depends on the operating mode being used.

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 1M ohm input 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.

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Measure Mode

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. PS When the switch is in the REV position it should be noted that the display does not place

a – annunciator before the value.

TX SIM function

The switch is not used for this function and has no effect at all.

STEP and RAMP modes

In both these modes the function switch is in the source (SCR) position and the NORM/OFF/REV switch performs in the same way as in the NORMAL operating mode i.e. conventional V and I measure/source.

3.2. Measure – Voltage

The unit measures dc voltage in three selectable ranges, 0 to 0.22V (displayed in mV), 0 to

2.2V and 0 to 22V (plus over-range to 50V).

SPECIAL NOTE: Although the top range is nominally 22V it can be safely used to measure voltages up to 50V.

• Set Function switch to MEAS

• Set OFF/V/I switch to V

• Set Range switch to the desired range

• Set Output switch to NO RM

• Connect the unit to the signal source observing correct polarity, the voltage will be

displayed with 3.5 or 4.5 resolution - see section 3.1.1.

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