Labkotec SET-1000 12 VDC Level Switch for One Sensor Instruction Manual

Labkotec SET-1000 12 VDC Level Switch for One Sensor

SYMBOLS

• Warning / Attention
• Pay special attention to installations at explosive atmospheres
• Device is protected by double or reinforced insulation

GENERAL

SET-1000 is a one-channel level switch. Typical applications are high level and low level alarms in liquid tanks, condensed water alarms, level control and alarms in oil, sand and grease separators. The LED indicators, push buttons and interfaces of the device are described in figure 1.

SET-1000 user interface features:

1. LED indicator for mains
2. LED indicators of alarm and fault
3. Reset button for alarm and fault
4. Test button
5. Connector for one Labkotec SET level sensor [Ex ia]
6. Potential-free relay outputs for monitoring and control purposes

SET-1000 can be used as a controller of a level sensor located in potentially explosive atmosphere (zone 0,1 or 2) due to intrinsically safe inputs of the device. The SET-1000 itself must be installed in a non-hazardous area.

INSTALLATION

The SET-1000 can be wall-mounted. The mounting holes are located in the base plate of the enclosure, beneath the mounting holes of the front cover. The connectors of the external conductors are isolated by separating plates. The plates must not be removed. The plate covering the connectors must be installed back after executing cable connections. The cover of the enclosure must be tightened so, that the edges touch the base frame. Only then do the push buttons function properly and the enclosure is tight. Before installation, please read the safety instructions in chapter 6 !

Cabling when using a cable junction box

If the sensor cable must be extended or there is a need for equipotential grounding, it can be done with the cable junction box. The cabling between the SET-1000 control unit and the junction box should be done with a shielded twisted pair instrument cable.
LJB2 junction box enables cable extension in potentially explosive atmospheres. In examples in Figure 4 the shields and excess wires have been connected to the same point in galvanic contact with the metallic frame of the junction box. This point can be connected to the equipotential ground through the ground terminal. Other components of the system that need to be grounded can also be connected to the same ground terminal. The wire used for equipotential grounding must be min. 2.5 mm² mechanically protected or, when not protected, the minimum cross-section is 4 mm². Please make sure, that the cable between SET-1000 and the sensor does not exceed maximum connection values – see Appendix 2. Detailed cabling instructions can be found in the instructions of particular Labkotec SET sensors.

• Junction box of type LJB2 include light alloy parts. When installing in explosive atmosphere, make sure, that the junction box is located so, that it can not be mechanically damaged or it will not be exposed to external impacts, friction etc. causing ignition of sparks.
• Make sure, that the junction box is closed properly.

Cabling when using cable joint

Connections of the sensor cable inside the cable joint are explained in figure 8. Cable shields and possible excess wires need to be connected to the same point in galvanic contact. Please make sure, that the sensor and cable between SET-1000 control unit and the sensor do not exceed the maximum allowed electrical parameters – see appendix 1 Technical data. IP rating of the cable joint is IP68. Make sure, that the cable joint is closed properly. If the sensor cable must be extended and there is a need for equipotential grounding, it should be done with the junction box LJB2. The cabling between the SET-1000 control unit and the junction box should be done with a shielded twisted pair instrument cable.

OPERATION AND SETTINGS

The SET-1000 control unit is initialized at the factory as follows. See a more detailed description in chapter 3.1 Operation.

• Channel 1 Alarm takes place when the level hits the sensor (high level alarm)
• Relay 1 Relay de-energizes in alarm and fault situations (so-called fail-safe operation). Relay 1 is resettable with the Reset button.
• Relay 2 Relay de-energizes in alarm and fault situations (so-called fail-safe operation). Operational delay for both relays is set to 5 seconds. The trigger level is normally at the middle of the sensor’s sensing element.

Operation
The operation of a factory-initialized SET-1000 is described in this chapter. If the operation is not as described here, check the settings (chapter 3.2.) and the operation (chapter 4) or contact a representative of the manufacturer.

Normal mode – no alarms

• The level in the tank is below the sensor.
• Mains LED indicator is on.
• Other LED indicators are off.
• Relays 1 and 2 are energized.

High level alarm

• The level has hit the sensor (sensor in the medium).
• Mains LED indicator is on.
• Alarm LED indicator is on.
• Buzzer on after 5 sec delay.
• Relays de-energize after 5 sec delay.

Fault alarm

• Sensor cable break, short circuit or a broken sensor, i.e. too low or too high sensor signal current.
  Mains LED indicator is on.

• Sensor cable Fault LED indicator is on after 5 sec delay.

• The relays de-energize after 5 sec delay.

• Buzzer is on after 5 sec delay.

Reset of an alarm

• When pressing the Reset push button.
• Buzzer will go off.
• Relay 1 energizes.
• Relay 2 will stay de-energized until the actual alarm or fault is off.

TEST FUNCTION
Test function provides an artificial alarm, which can be used to test the function of the SET-1000 level switch and the function of other equipment, which is connected to SET-1000 via its relays. Attention ! Before pressing the Test button, make sure that the change of relay status does not cause hazards elsewhere !

Normal situation

• When pressing the Test push button:
• Alarm and Fault LED indicators are immediately on.
• Buzzer is immediately on.
• Relays de-energize after 2 sec of continuous pressing.
• When the Test push button is released:
• LED indicators and buzzer go immediately off.
• Relays energize immediately.

Alarm on

• When pressing the Test push button:
• Fault LED indicator is immediately on.
• Alarm LED indicator remains on.
• Buzzer remains on. If it has been reset earlier, it will return to be on.
• If relay 1 was already reset, it will de-energize again after 2 sec. of continuous pressing.
• Test will not affect relay 2, because it is already in alarm status.
• When the Test push button is released:
• The device returns without delay to the preceding status.

Fault alarm on

• When pressing the Test push button:
• The device does not react to the test at all.

Altering settings

• If the default situation described above does not apply to the site being measured, the following device settings can be changed.

• Operating direction
  High-level or low-level function (increasing or decreasing level).

• Operation delay
  Two alternatives: 5 sec or 30 sec.

• Trigger level
  The trigger point of an alarm in the sensor’s sensing element.

• Buzzer
  The buzzer can be disabled.

• The following tasks must only be executed by a person with proper education and knowledge of Ex-i devices. We recommend, that when altering the settings the mains voltage is off or the device is initialized before the installation is executed.

The settings are changed using the upper circuit board’s switches (MODE and DELAY) and potentiometer (SENSITIVITY) and the lower circuit board’s jumpers (Sensor selection and Buzzer). The switches are displayed in their default setting in the circuit board figure (figure 9).

OPERATING DIRECTION (MODE)

OPERATIONAL DELAY SETTING (DELAY)

TRIGGER LEVEL SETTING (SENSITIVITY)

TROUBLESHOOTING

• Problem: MAINS LED indicator is off
• Possible reason: Supply voltage is too low or the fuse is blown. The transformer or MAINS LED indicator is faulty.
• To do:

1. Check if the two pole main switch is off.
2. Check the fuse.
3. Measure the voltage between poles + and -.

Problem: FAULT LED indicator is on

Possible reason: Current in sensor circuit too low (cable break) or too high (cable in short circuit). The sensor might also be broken.
To do:

1. Make sure, that the sensor cable has been connected correctly to the SET-1000 control unit. See sensor-specific instructions.
2. Measure the voltage separately between the poles 10 and 11. The voltages should be between 10,3….11,8 V.
3. If the voltages are correct, measure the sensor current. Do as follows:
4. Disconnect the sensor’s [+] wire from the sensor connector (pole 10).
5. Measure short circuit current between [+] and [-] poles.
6. Connect mA-meter as in Figure 10. Make a comparison to the values in Table 1. More detailed current values are to be found in the instructions of specific sensor’s instructions.

Connect the wire back to the connector.
If the problem can not be solved with the above instructions, please contact Labkotec Oy’s local distributor or Labkotec Oy’s service.

Attention! If the sensor is located in an explosive atmosphere, the multimeter must be Exi-approved!

REPAIR AND SERVICE

The mains fuse (marked 315 mAT) can be changed to another glass tube fuse 5 x 20 mm / 315 mAT complying EN IEC 60127-2/3. Any other repair and service works on the device may be carried out only by a person who has received training in Ex-i devices and is authorized by the manufacturer.

SAFETY INSTRUCTIONS

• SET-1000 level switch must not be installed in an explosive atmosphere. Sensors connected to it may be installed in explosive atmosphere zone 0,1 or 2.
• In case of installations in explosive atmospheres, the national requirements and relevant standards as EN IEC 60079-25 and/or EN IEC 60079-14 must be taken into account.
• If electrostatic discharges can cause hazards in the operating environment, the device must be connected into the equipotential ground according to requirements with regards to explosive atmospheres. Equipotential grounding is made by connecting all conductive parts into same potential e.g. at the cable junction box. The equipotential ground must be earthed.
• When executing service, inspection and repair in an explosive atmosphere, the rules in standards EN IEC 60079-17 and EN IEC 60079-19 about instructions of Ex-devices must be obeyed.

APPENDICES

Appendix 1 Technical data

SET-1000

Dimensions

| ****

175 mm x 125 mm x 75 mm (L x H x D)

Enclosure

| ****

IP 65, material polycarbonate

Cable glands

| ****

4 pcs M16 for cable diameter 5-10 mm

Operating environment| Temperature: -25 °C…+50 °C

Max. elevation above sea level 2,000 m Relative humidity RH 100%

Suitable for indoor and outdoor use (protected from direct rain)

Supply voltage| 11-17 VDC

Fuse 5 x 20 mm 315 mAT (EN IEC 60127-2/3)

The device is not equipped with a mains switch

Power consumption| Max. 1,2 VA.

Typical (no alarms) 0,9 VA.

Sensors

| ****

One Labkotec SET sensor

Max. resistance of the current loop between the control unit and a sensor

| ****

75 Ω. See more in appendix 2.

Relay outputs

| ****

Two potential-free relay outputs 250 V, 5 A, 100 VA

Operational delay 5 sec or 30 sec. Relays de-energize at trigger point. Operation mode selectable for increasing or decreasing level.

Electrical safety

| ****

EN IEC 61010-1, Class II POLLUTION DEGREE 2

| ****

, CAT II / III

Insulation level

Sensor / Mains supply voltage

| 375V (EN IEC 60079-11)
EMC| ****

Emission Immunity

| ****

EN IEC 61000-6-3

EN IEC 61000-6-2

Ex-classification

Special conditions (X)

ATEX IECEx

| II (1) G| [Ex ia Ga] IIC|
(Ta = -25 C…+50 C)
EESF 21 ATEX 022X
IECEx EESF 21.0015X
Electrical parameters| Um = 23 V Io = 55 mA R = 404 Ω

Co = 608 nF Co = 3,84 µF

| Uo = 14,7 V Po = 297 mW

Lo = 10 mH Lo = 30 mH

| ****

Lo/Ro = 116,5 µH/Ω Lo/Ro = 466 µH/Ω

Characteristic curve of the output voltage is trapezoidal.
IIC
IIB
Attention ! See appendix 2.
Year of manufacture

See the serial number from the type plate

| xxx x xxxxx xx YY x

where YY = year of manufacture (e.g. 19 = 2019)

Appendix 2 Electrical parameters
When installing the device, make sure that the electrical values of the cable between SET-1000 and the sensor never exceed maximum electrical parameters. The cabling between the SET-1000 control unit and the cable extension junction box/cable joint must be executed as in Figure 4 / 8 Extension cable should be shielded and paired with twisted instrument cable. Due to the non-linear characteristics of the sensor voltage, the interaction of both, capacitance and inductance, must be taken into account. The table below indicates the connecting values in explosion groups IIC and IIB. In explosion group IIA the values of the group IIB can be followed.

• Uo = 14,7 V
• Io = 55 mA
• Po = 297 mW
• R = 404 Ω

The characteristics of the output voltage is trapezoidal.

• Lo/Ro = 116,5 H/Σ (IIC) and 466 H/Σ (IIB)
• Table 2.Electrical parameters

The maximum length of the sensor cable is determined by the resistance (max. 75 Ω) and other electrical parameters (Co, Lo and Lo/Ro) of the sensor circuit.

Example: Determining the maximum cable length
Instrument cable with the following characteristics is used:

• DC resistance of a twin wire at + 20°C is approx. 81 Ω / km.
• Inductance is approx. 3 μH / m.
• Capacitance is approx. 70 nF/km

Influence of resistance The estimate for additional resistances in the circuit is 10 Ω. The max length of the cable is then (75 Ω – 10 Ω) / (81 Ω / km) = 800 m. The influence of inductance and capacitance of an 800 m cable is:

Influence of inductance Total inductance is 0,8 km x 3 μH/m = 2,4 mH. The sum value of the cable and e.g. SET/OS2 sensor [Li = 30 μH] is 2,43 mH. The L/R ratio is thus 2,4 mH / (75 – 10) Ω = 37 μH/Ω, which is less than the maximum allowed value 116,5 μH/Ω.

Influence of capacitance Cable capacitance is 0,8 km x 70 nF/km = 56 nF. The combined value of the cable and the e.g. SET/OS2 sensor [Ci = 3 nF] is 59 nF. When compared to the values in Table 2, we can summarize that the above values do not limit the use of this particular 800 m cable in explosion groups IIB or IIC. The feasibility of other cable types and sensors for different distances can be calculated accordingly.

EU DECLARATION OF CONFORMITY

• Labkotec Oy
• Myllyhaantie 6, FI-33960 Pirkkala, Finland
• Tel. +358 29 006 260
• info@labkotec.fi

References

• Labkotec.fi - Measures for a better tomorrow

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