Conrad 11 03 90 Operating Instructions Manual

The Conrad 11 03 90 is a professional-grade electronic measurement and testing instrument designed for laboratory and field use. It features high-precision digital readouts, multiple measurement modes, data logging capabilities, and robust connectivity options. Below are key sections covering safety, features, setup, operation, calibration, maintenance, and troubleshooting.

1. Features at a Glance 2. Safety Instructions 3. Unpacking and Inspection 4. Technical Specifications 5. Front Panel Controls 6. Initial Setup and Power 7. Basic Measurement Procedures 8. Advanced Functions 9. Calibration 10. Maintenance & Storage 11. Troubleshooting

Features at a Glance

Key components: High-resolution LCD display, Function keys, Rotary encoder, Measurement terminals, USB and RS-232 ports, Battery compartment, Carrying handle.

Feature	Description
Measurement Range	Wide range for voltage, current, resistance, and frequency
Display	Backlit LCD with digital and analog bar graph
Data Logging	Internal memory for storing measurement results
Connectivity	USB and RS-232 for PC interface and data transfer
Power Options	Rechargeable battery or AC adapter operation
Auto-Ranging	Automatic selection of optimal measurement range
Hold Function	Freezes current reading on display
Relative Mode	Measures difference from a reference value
Protection	Overload protection on all ranges
Carrying Case	Included for transport and storage

Safety Instructions

Read all safety information before operating the device.

Use only the supplied AC adapter or specified batteries.
Do not use the instrument in wet or damp conditions.
Ensure test leads are in good condition and properly rated.
Do not exceed the maximum input ratings specified in the manual.
Disconnect test leads before changing functions or ranges.

WARNING! Risk of electric shock. Do not measure voltages exceeding 600V CAT III. Use appropriate personal protective equipment when working with hazardous voltages.

Unpacking and Inspection

Carefully unpack and verify all components are present.

Main unit (Conrad 11 03 90)
Test leads (red and black)
AC power adapter
USB cable
Protective carrying case
Quick start guide and this manual

CAUTION! Inspect the instrument for any signs of damage from shipping. Do not use if damaged.

Technical Specifications

Model: Conrad 11 03 90
DC Voltage: 0.1mV to 1000V, ±(0.5% + 3 digits)
AC Voltage: 0.1mV to 750V RMS, ±(0.8% + 5 digits)
DC/AC Current: 0.1µA to 10A
Resistance: 0.1Ω to 50MΩ
Frequency: 0.1Hz to 10MHz
Display: 4½ digit, 5000 count LCD
Power Supply: 6 x 1.5V AA batteries or 9V DC adapter
Operating Temp: 0°C to 40°C (32°F to 104°F)
Dimensions: 190 x 90 x 40 mm
Weight: Approx. 400g (including batteries)

Front Panel Controls

Access functions via rotary switch and soft keys.

Rotary Switch: Selects primary measurement function (V DC, V AC, A DC, A AC, Ω, Hz, Continuity, Diode).

Function Keys: RANGE (manual/auto), HOLD, REL (relative), MIN/MAX, MENU for setup options.

Display Indicators: Shows function, range, units, battery status, and warning symbols.

Input Terminals: COM (common), VΩHz (voltage/resistance/frequency), mA (milliamps), 10A (high current).

Initial Setup and Power

Power on the device and configure basic settings.

Insert batteries: Open compartment, install 6 AA batteries observing polarity.
Connect AC adapter: Plug into DC 9V jack and wall outlet for extended use.
Power on: Turn rotary switch from OFF to desired function.
Display test: All segments should illuminate briefly.
Set preferences: Use MENU to configure beeper, backlight timeout, auto power-off.

Tip: For best accuracy, allow the instrument to stabilize at room temperature for 30 minutes before critical measurements.

Basic Measurement Procedures

Follow these steps for common measurements.

Voltage (DC/AC): Set rotary to V⎓ or V~. Connect red lead to VΩHz, black to COM. Apply probes to circuit.
Current (DC/AC): Set rotary to A⎓ or A~. For <600mA, use mA terminal. For up to 10A, use 10A terminal. Break circuit and connect meter in series.
Resistance: Set rotary to Ω. Ensure circuit is de-energized. Connect probes across component.
Continuity: Set rotary to •))) symbol. Audible beep indicates resistance <50Ω.
Diode Test: Set rotary to diode symbol. Displays forward voltage drop (0.3V-0.8V typical).

WARNING! Never connect the meter to a voltage source when set to current or resistance mode. This can damage the meter and cause injury.

Advanced Functions

Utilize the instrument's enhanced capabilities.

Data Logging: Press and hold HOLD to enter logging mode. Select interval via MENU. Press HOLD again to stop.

MIN/MAX Recording: Press MIN/MAX to capture lowest and highest readings during a session.

Relative Measurement: Press REL to set current reading as zero reference. Subsequent readings show difference.

PC Interface: Connect via USB. Install software to graph, record, and analyze measurements remotely.

Calibration

Periodic calibration ensures measurement accuracy.

Allow instrument to warm up for at least 30 minutes.
Access calibration mode: Turn off, then press and hold RANGE and MENU while turning rotary switch to V DC.
Follow on-screen prompts to apply known reference voltages/currents to specified terminals.
Save calibration data when procedure is complete.

CAUTION! Calibration should be performed by qualified personnel using traceable standards. User calibration may void warranty.

Maintenance & Storage

Proper care extends instrument life.

Clean exterior with a soft, dry cloth. Do not use solvents or abrasives.

Replace batteries when low battery icon appears. Remove batteries if storing for more than 3 months.

Store in the provided case in a cool, dry place away from direct sunlight and extreme temperatures.

CAUTION! Do not attempt to open the case. Internal repairs must be performed by authorized service personnel.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No display	Dead batteries, power off	Replace batteries; ensure rotary switch is not in OFF position.
Inaccurate readings	Weak batteries, wrong range	Replace batteries; select auto-range or correct manual range.
Display shows "OL"	Overload, input too high	Disconnect input; select higher range if in manual mode.
No continuity beep	Open circuit, probes not connected	Check circuit continuity; ensure probe tips make good contact.
USB not recognized	Driver not installed, faulty cable	Install software/driver from CD; try a different USB cable.

Reset: Remove batteries and AC adapter for 5 minutes to perform a soft reset.

Service: For technical support or service, contact Conrad Technical Support or refer to your local distributor.