DOLD VARIMETER IMD RN 5897/321 Traduzione delle istruzioni originali - Pagina 2

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Function

The device is supplied with DC auxiliary voltage via terminals A1(+) / A2.

Switching on the auxiliary voltage (Power-On) is followed by an internal

self-test for 12 s (see „Device test functions"). The test process is visible

with the status LED. After this, measurement of the insulation resistance

in the measuring circuits begins and the status LED changes into green.

Measuring circuit

(Insulation measurement between terminals L(+)/L(-) and PE)

The insulation monitor RN 5897/321 can only be used with a coupling

device. Max. mains voltage and connection diagrams have to be observed!

To connect the insulation Monitor RN5897/320 to a coupling device the

terminals with identical designations are connected (VSG1/L(+) and VSG2,

L(-)). The votage system to be monitored is connected to L(+) and L(-) of

the coupling device.

The type of the voltage system or the connection method (AC, DC, 3NAC)

has to be correctly adjusted via Modbus.

Also the terminals PE1 and PE2 have to be connected with 2 separate

wires to the protective earth. An interruption of a wire also causes a fault

signal (see section "Behavior on faulty connection"). The monitoring of

the PE connection cannot be de-activated.

To measure the insulation resistance an active measuring voltage with

changing polarity is connected between L(+)/L(-) and PE1/PE2.

At the end of a measuring cycle the actual insulation resistance is produced

and indicated. The relays for alarm K1 and pre-alarm K2 switch when

dropping under the adjusted response values. In addition the status LED

changes to orange color on pre-alarm or to red color on alarm.

The current measured value is output via Modbus. An asymetric insulation

resistance against „+" or „-" is also output via Modbus (only with DC networks

resp. insulation faults on the DC side).

Manual reset of fault message

The manual reset of insulation fault messages can be set via Modbus (alarm

memory). If the manual reset is activated, the insulation fault signals of the

measuring circuit remain saved when the adjusted response value is not

reached, even if the insulation resistance later goes back to healthy state

again. The minimum value of the insulation resistance is stored and can

be read out via Modbus. Pressing the „Reset" button on the front side for

2 s, the alarm signal and the stored minimum value are reset if the actual

insulation resistance is in healthy state.

The device can also be reset with a Modbus command.

Indicator relay for insulation fault signal

For the indicator relays K1 (contacts 11-12-14, for alarm) and K2 (contacts

21-22-24, for pre-alarm) the function can be set via Modbus to energized

on trip or de-energized on trip. When energised on trip the relays energize

when the value drops below the setting, when de-energised on trip, the

relays de-energize when the value drops below the setting. The status of

the indicator relays is also shown via Modbus.

Disable the measuring function

Using the external control input X1/X2 or via Modbus command the

measuring function of the RN 5897/321 can be disabled. This could be

used when several isolated voltage systems with individual insulation

monitors need to be coupled.

The measuring voltage is set to -90V (negative measuring phase) and

the evaluation of the measurement is stopped. The output relays switch

according to the current measured values. If the measurement is disabled

the status LED flashes continuously orange. Please be aware, only the

evaluation of the measurement is stopped and the measuring pulse is

interrupted! A high resistive disconnection to PE does not take place

(see internal resistance).

Function

Broken wire detection

As described in section "Measuring circut", the measuring circuits L(+) /

L(-) and the protective conductors PE1/PE2 are constantly monitored for

wire breaks – not only at Power-On or a manual or occasional automatic

test. The response time of PE1/PE2 monitoring is only a few seconds. The

response time of monitoring of L(+)/L(-) can be up to approx. 2 min. Broken

wire detection between L(+)/L(-) is performed via coupled alternating

voltage. This alternating voltage is short-circuited if the terminals are

connected to the connected mains at low-resistance. The device detects

that the mains to be monitored is properly connected.

Since this broken wire detection is carried out with alternating voltage, large

capacitances should be avoided between L(+)/L(-), since the capacitive

reactance of these capacitances also short-circuits this alternating voltage.

The device would no longer detect a connection fault on L(+)/L(-).

Especially parallel lines should be prevented over larger distances.

If larger capacitances between L(+)/L(-) cannot be avoided or if the coupled

alternating voltage interferes with the system, the broken wire detection can

be de-activated via Modbus. Monitoring deactivated, monitoring only during

device test or continuous monitoring (every 2 minutes for 10 s) are the

possible options. If the broken wire detection on L(+)/L(-) is de-activated

no AC voltage is injected. The broken wire detection on PE1/PE2 cannot

be de-activated.

Device test functions

Principally, 2 different test functions are implemented: The "self-test" and

the "expanded test":

The self-test of the device is performed automatically after Power-On and

every full operating hours. It can also be triggered manually at any time by

pressing the "Test" button at the device front for 2 s or via Modbus command.

With the self-test, contrary to the expanded test, the status of the Indicator

relays is not affected; the sequence is as follows:

The self test is indicated by the status LED with flash code 1 in orange colour.

Additionally, it is output via Modbus that the device is in test mode. First

the negative measuring pules is activated for about 5 s and the internal

measuring circuit is checked on failures. Then the positive measuring

pulse is activated for about 5 s and more internal tests are performed. If no

failures are detected, the normal measurement continuous. The extended

test is started, when during or at the end of above procedure (12 s) the

button "Test" is pressed again for 2 s or triggered via a Modbus command.

The procedure is the same as above (2 measuring phases with 5 sec each)

but in addition the output relays K1 and K2 go into alarm state. The Status

LED shows flash code 2 in orange colour and via Modbus it is signalled that

the device is in extended test mode. The test phases will be continuously

repeated. The extended test can be finished after the first complete

sequence (approx. 10 sec) by pressing the "reset" button for 2 seconds.

The device starts the insulation monitoring again. The extended test can

also be ended via a Modbus command.

Self test (Test 1)

Insulation

measurement

Duration: approx. 12s

measurement

Positive

Measuring voltage

Negative

Test signal

Reset signal

Alarm

Relay state K1 and K2

No Alarm

Test signal: Button Test > 2 s or X1/X2 > 1.5 s and < 10 s or

via Modbus command

Reset signal: Button Reset > 2 s or X1/X2 < 1.5 s or

via Modbus command

To initiate the extended test (Test 2) the test signal must be operated

within the self test (Test 1) again.

The reset signal has here no function, as the first complete sequence

of extended test (Test 2) is not finished.

Self test (Test 1)

Continuous extended

Insulation

Duration: approx. 12s

test (Test 2)

Duration: approx. 10s

12.07.22 en / 604A

Insulation

measurement

M12462