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©2017 SAT-Kabel GmbH

©2017 SAT-Kabel GmbH

The

 IRM 20

 operates based on the reflections of electric pulses on open or closed cable ends. 

These electric pulses are send out in time constant intervals.

The device calculates the length of the cable by measuring the time between the sending of 

the impulse and his return.

This depends on the velocity factor of the cable which is considered in the calculation.

The velocity factor (v/c or pulse velocity) declares the propagation of electrical signals in the 

cable in relation to the speed of light. It depends on the used type of coaxial cable and can be 

found, for example, in the manufacturer's data sheet for the cable in question. Alternatively it 

has to be determined "at the place" (locally).

To make work easier the 

IRM 20

 has a persistent memory with 20 predefined cable types and 

their corresponding velocity factors. These can be modified.

3. Functional principle

3. Operation

3.1 Switch on/ off

3.2 Measuring

3.3 Velocity factor

3.3.1 Set a velocity factor

Press the key briefly

Press the Key briefly

Press the key briefly

and change values ongoing

Long press the key

and move the cursor

press an hold key

for 5 seconds …

… until MENU appears

Press the key for

 2 seconds 

Press the key briefly again

BATTERY INDICATOR

IRM 20

 operate

IRM 20

 switched of

Without any key pressed the 

IRM 20

 turns off automatically after 2 minutes to save battery.

If the battery voltage becomes lower than 5,8 V a battery icon appears in the display.

At a battery voltage of 5,5 V the 

IRM 20

 switches off.

On switch on again the IRM 20 shows the last 

used memory entry.

With the IRM 20 switched on press the key 

briefly to select a memory entry between P1 

and P30.

P0 … P9

P9 … P0

The cable to be measured must be connected only after selecting the required shortening 

factor. Then read the length of the cable in the display. If there is a short circuit in the 

cable, the cable length appears 

>>K<<

 in the display.

Notes

!

the velocity factor of the cable has always to be selected before   

 

       the measurement of the length

!

if the velocity factor is unknown, choose an approximate value

            and determine the fault from both ends of the cable

!

if a terminating resistor is installed which corresponds to the wave         

            impedance of the cable a length measurement is not possible

            (the send pulse will not be reflected at the cable end)

!

to minimize measuring errors determine the cable from both ends

The velocity factor declares the propagation of electrical signals in the cable in relation to 

the speed of light. It affects the accuracy of the measurement significant. The velocity 

factor is in general:

 

        Electric cable 

                 

0,49–0,57 

(ca. 0,53)

 

Telephone cable 

    0,58–0,65 

       (ca. 0,62)

 

Coaxial cable with PE dielectric 

    0,66

 

Coaxial cable with foam PE 

    0,77–0,85 

       (ca. 0,83)

 

Air insolation 

    0,88–0,92

After 8 s display

OFF

PROGRAMMING MENU

MEMORY ENTRY

P0 … P9

1| MEMORY ENTRY ON/OFF
2| VELOCITY FACTOR
    (two decimal places 0,xx)

Summary of Contents for IRM?20

Page 1: ...Operating instructions Chemnitzer Straße 11 09217 Burgstädt Satelliten und Kabelfernsehanlagen Industrievertretung GmbH SAT Kabel IRM 20 Pulse reflectometer ...

Page 2: ...use If you have questions about this instrument or suggestions for further improvements please get in touch with us This instruction has been performed to the best of our knowledge Developments and technical amendments are subject to change without notice Topical made operating instructions in a PDF format can also downloaded from our Internet homepage www sat kabel de 2017 SAT Kabel GmbH ...

Page 3: ...the invoice to a customer by a monteur It also can be very helpful in networking to check the segment length of a network In addition it helps in localization of damages on cables The distance to the defective point is displayed immediately and whether it is a short circuit or a cut The IRM 20 can measure all usual 2 core wires no matter if it are coaxial cables or normal installation cables Excep...

Page 4: ... has a persistent memory with 20 predefined cable types and their corresponding velocity factors These can be modified 3 Functional principle 3 Operation 3 1 Switch on off 3 2 Measuring Press the key briefly Press the key for 2 seconds Press the key briefly again BATTERY INDICATOR IRM 20 operate IRM 20 switched of Without any key pressed the IRM 20 turns off automatically after 2 minutes to save b...

Page 5: ...esponds to the wave impedance of the cable a length measurement is not possible the send pulse will not be reflected at the cable end to minimize measuring errors determine the cable from both ends The velocity factor declares the propagation of electrical signals in the cable in relation to the speed of light It affects the accuracy of the measurement significant The velocity factor is in general...

Page 6: ...y Therefor connect a cable with a known length 50 to 100 meter at the IRM 20 After that modify the velocity factor until the displayed length matches the length of the cable Maximal cable length 1000 m low loss cable Resolution 1 m Accuracy 1 2 m Measuring connection 4 mm banana jack 75 ohms Output pulse 4 V Rechteck 30 kHz Display LCD 2 8 Zeichen illuminated Casing dimensions 120 mm 60 mm 25 mm W...

Page 7: ...usings bags connecting cables this guarantee is valid for 6 month from the purchasing date The guarantee claim expires at matings by the purchaser or third persons At defects caused by improper handling or operating by wrong installation or store by improper connection or mounting no guarantee is granted For not justified demand of our service we charge for our service the usual payment for materi...

Page 8: ...Telefon 49 0 3724 6665 0 Telefax 49 0 3724 6665 44 info sat kabel de www sat kabel de Irrtümer sowie Änderungen im Zuge technischer Weiterentwicklung vorbehalten 2017 04 07 SAT Kabel ...

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