GDM-RC-100-T

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WIKA · SF6 gas solutions · Family GDM

Hybrid gas density monitor with reference chamber

Name: Hybrid gas density monitor with reference chamber
Brand: WIKA

With Modbus ® interface or analogue 4 ... 20 mA signal

Range

0…12.5 bar

Output

Modbus RTU · 4 ... 20 mA

Protection

IP67

RoHS

Price

On request

Depends on configuration

Request a quote

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Description

Gas density is a crucial operating parameter for high-voltage switchgear. If the required gas density is not present, safe operation of the plant cannot be guaranteed.

The WIKA gas density measuring instruments provide reliable warnings against dangerously low gas levels, even under extreme ambient conditions. If the gas density drops as a result of a leakage, the switch contacts will switch. In addition to the traditional gas density monitor, with the model GDM-RC-100-T high-precision sensing technology and evaluation electronics are incorporated.

Via the on-site indication, the pressure based on 20 °C [68 °F] can be read directly on the instrument. With the integrated switch contacts, simple switching tasks can be realised quickly and without complication. The integrated or attached Modbus ® interface or 4 ... 20 mA sensing technology enable remote monitoring of the plant.

Special features

Ideally suited for smart grid or modernisation projects
Modbus ® delivers measured values for pressure, temperature and gas density as a digital signal
The 4 ... 20 mA version outputs the absolute pressure at 20 °C [68 °F] or the gas density in g/l as an analogue signal
Suitable for SF<sub>6</sub> and alternative insulating gases
Complete on-site indication of the density and vacuum range on a 100 mm [3.94 in] dial

Identification

Model	GDM-RC-100-T
Product family	GDM
Subcategory	Hybrid gas density monitor with reference chamber

Measuring range

Pressure ranges	0…10 bar · 0…12.5 bar
Density reference temperature	20 °C

Process conditions

Process connection

G1/2 B

Electrical characteristics

Output signal	Modbus RTU · 4 ... 20 mA
Switching contacts	4

Materials

Wetted parts material

Stainless steel

Operating environment

Ambient temperature	−40…+80 °C
IP rating	IP67

Certifications and approvals

Certifications

RoHS

Additional details

Temperature compensation

Yes

Tables from datasheet

Basic information

Measurement principle	Reference gas measurement
Nominal size of the optical indication	100 mm[3.94 in]
Self-indication in case of malfunction	Integrated into the instrument, the switch contact is actuated in case of leakage in the reference chamber

Measuring element

Type of measuring element	Bellows measuring system with reference chamber, piezo pressure sensor with temperature compensation

Accuracy specifications

Switching accuracy Calibration pressure established by means of reference isochore, generated by Prof. Bier
-1 ...+5 bar at 20 °C [-14.50 ... +72.51 psi at 68 °F]	±70 mbar [±1.01 psi] at calibration pressure at 20 °C [68 °F], gaseous phase ±100 mbar [±1.45 psi] at calibration pressure at -30 ...+50 °C [-22 ...+122 °F], gaseous phase
-1 ...+9 bar at 20 °C [-14.50 ... +130.53 psi at 68 °F]	±100 mbar [±1.45 psi] at calibration pressure at 20 °C [68 °F], gaseous phase ±150 mbar [±2.17 psi] at calibration pressure at -30 ...+50 °C [-22 ...+122 °F], gaseous phase
-1 ... +11.5 bar at 20 °C [-14.50 ... +166.79 psi at 68 °F]	±150 mbar [±2.17 psi] at calibration pressure at 20 °C [68 °F], gaseous phase ±200 mbar [±2.90 psi] at calibration pressure at -30 ...+50 °C [-22 ...+122 °F], gaseous phase
Calibration pressure	First switch point below filling pressure
Indication accuracy
-1 ...+5 bar at 20 °C [-14.50 ... +72.51 psi at 68 °F]	±70 mbar [±1.01 psi] at calibration pressure at 20 °C [68 °F], gaseous phase ±100 mbar [±1.45 psi] at calibration pressure at -30 ...+50 °C [-22 ...+122 °F], gaseous phase
-1 ...+9 bar at 20 °C [-14.50 ... +130.53 psi at 68 °F]	±100 mbar [±1.45 psi] at calibration pressure at 20 °C [68 °F], gaseous phase ±150 mbar [±2.17 psi] at calibration pressure at -30 ...+50 °C [-22 ...+122 °F], gaseous phase
-1 ... +11.5 bar at 20 °C [-14.50 ... +166.79 psi at 68 °F]	±150 mbar [±2.17 psi] at calibration pressure at 20 °C [68 °F], gaseous phase ±200 mbar [±2.90 psi] at calibration pressure at -30 ...+50 °C [-22 ...+122 °F], gaseous phase
Switch hysteresis	Measuring range	Hysteresis level
-1 ...+5 bar at 20 °C [-14.50 ... +72.51 psi at 68 °F]	Typically < 90 mbar[< 1.30 psi] 1)
-1 ... +7.5 bar at 20 °C [-14.50 ... +108.77 psi at 68 °F]	Typically < 150 mbar[< 2.17 psi] 1)
-1 ... +11.5 bar at 20 °C [-14.50 ... +166.79 psi at 68 °F]	Typically < 220 mbar[< 3.19 psi] 1)
Lower switch hysteresis on request

Measuring range

Measuring range	■ 0 ... 10 bar abs. at 20 °C [0 ... 145.03 psi abs. at 68 °F] SF₆ gas ■ 0 ... 12.5 bar abs. at 20 °C [0 ... 181.29 psi abs. at 68 °F] SF₆ gas
Maximum overpressure	1.43 times the measuring range
Minimum bursting strength	30 bar [435.11 psi]
Dial
Scale range	End of measuring range	1.3 bar or 1.8 bar [18.85 psi or 26.10 psi] above the first switch point and below the filling pressure
Scale graduation	■ Single scale (divided into sections of different colours) ■ Double scale (divided into sections of different colours) ■ Triple scale (divided into sections of different colours)
Material	Aluminium

View all (20)

Process connection

Standard	EN 837
Thread size	G1/2 B
Connection	Axial or radial
Spanner flats	22 mm[0.86 in]
Material	Stainless steel

Switch contacts

Switch model	Potential-free change-over contact
Number of switches	■ 1 x switch contact ■ 2 x switch contact ■ 3 x switch contact ■ 4 x switch contact Up to four switch contacts possible as change-over contacts
Switching function	Change-over contact
Switching direction	■ Falling density ■ Rising density
Switch point setting	In accordance with customer specification, max. difference of lowest to highest contact: 4 bar [58.01 psi]
Maximum switching cycles	10,000 mechanical and electrical
Insulation resistance of contact	> 100MΩ
Min. switching current	10mA
Min. switching voltage	12V
Circuits	Galvanically isolated
Monitoring functions
Self-monitoring	Integrated into the instrument, the switch contact is actuated in case of leakage in the reference chamber

Electrical characteristics

Auxiliary power [V]	Resistive load [A]	Inductive load [A]
≤ DC 30	5 1)	3 1)
≤ DC 50	1	1
≤ DC 75	0.75	0.75
≤ DC 125	0.5	0.03
≤ DC 250	0.25	0.03
≤ AC 125	5 1)	2 1)
≤ AC 250	5 1)	2 1)

Electrical connection

Connection type	12-pin TTI plug-in terminal
Wire cross-section	■ Min.0.25mm 2 ■ Max.2.5mm 2
Grounding	In cable socket

Material

Material (wetted)
Reference chamber (pressure element)	Stainless steel, filled with reference gas
Process connection	Stainless steel
Material (in contact with the environment)
Case and cover	Aluminium die-casting, powder-coated
Cable gland of the switch contacts	→ For cable glands, see 'Versions of cable glands for model GDM-RC-100-T with integrated gas density sensor'
Movement	Brass
Pointer	Aluminium, black
Window	Laminated safety glass
Dial	Aluminium

Operating conditions

Place of use	Indoor/Outdoor
Altitude	Up to 2,000 m[6,562 ft] above sea level
Medium temperature range	-40 ...+80 °C [-40 ...+176 °F], gaseous phase
Operating temperature	-40 ...+80 °C [-40 ...+176 °F], gaseous phase
Ambient temperature range	-40 ...+80 °C [-40 ...+176 °F], gaseous phase
Storage temperature	-40 ...+70 °C [-58 ...+158 °F]
Humidity	≤ 95 %relative humidity
Condensation	Non-condensing Compensating diaphragm against condensation
Helium leak test	≤ 1 x 10 -8 mbar x l/s
Vibration resistance	4g at 50 mbar [0.72 psi] distance from the switch point, no contact bounce (20 ...80 Hz)
Shock resistance	■ 50g / 11 ms, no contact bounce with 200 mbar [2.90 psi] distance from the switch point ■ 150g without damage
Ingress protection of the complete instrument	■ IP65, IP67 for versions with integrated gas density sensor ■ IP67 for versions with attached gas density sensor
Permissible pollution degree	2 (per EN 61010-1)
Weight in kg	On request (depending on configuration)

Packaging and instrument labelling

Product label	Lasered onto the reference chamber, highest weather resistance

Dielectric strength test

Electric strength	■ 2 kV pin on grounding (case) ■ 2 kV pin on pin (switch contact to switch contact) ■ 1 kV pin on pin within the switch contact - 1 minute

Compensated pressure range in bar abs. at 20 °C [psi abs. at 68 °F] (g/l SF₆)	Pressure in bar abs. [psi abs.]	Temperature	Output parameters	Output signal
0 …2(12.28) [0 ... 29.00]	0 …2.4 [0 ... 34.80]	-40 …+80 °C [-40 ...+176 °F]	■ Density ■ Pressure at 20 °C [68 °F] ■ Pressure ■ Temperature	Modbus ® RTU
0 …3(18.65) [0 ... 43.51]	0 …3.7 [0 ... 53.66]
0 ... 6 (38.87) [0 ... 87.02]	0 ... 7.5 [0 ... 108.77]
0 …8(53.4) [0 ... 116.03]	0 …10.1 [0 ... 146.48]
0 …10(68.96) [0 ... 145.03]	0 …12.9 [0 ... 187.09]
0 …12(85.79) [0 ... 174.04]	0 …15.7 [0 ... 227.70]
0 …16(124.64) [0 ... 232.06]	0 …21.3 [0 ... 308.93]

Accuracy specifications

Accuracy 1)
Compensated pressure ranges in bar abs. at 20 °C [psi abs. at 68 °F] (g/l SF₆) 0 …2(12.28) [0 ... 29.00] 0 …3(18.65) [0 ... 43.51] 0 ... 6 (38.87) [0 ... 87.02]	For -40 ... -20 °C [-40 ... -4 °F] For -20 ...+80 °C [-4 ...+176 °F]	■ ±2% ■ ±1.5% ■ ±1.25% ■ ±0.75%

Accuracy specifications

Compensated pressure ranges in bar abs. at 20 °C [psi abs. at 68 °F] (g/l SF₆) 0 …8(53.4) [0 ... 116.03] 0 …10(68.96) [0 ... 145.03] 0 …12(85.79) [0 ... 174.04] 0 …16(124.64) [0 ... 232.06]	For -40 ...+80 °C [-40 ...+176 °F]	■ ±1.25% ■ ±0.6%
Pressure accuracy	■ ±1 %at 20 °C [68 °F] ■ ±0.2 %at 20 °C [68 °F]
Temperature accuracy	±1.5 K
Reference conditions	Per IEC 61298-1

Compensated pressure range in bar abs. at 20 °C [psi abs. at 68 °F] (g/l SF₆)	Accuracy 1)	Output parameters	Output signal
0 …2(12.28) [0 ... 29.00]	■ ±2% ■ ±1.5%	Absolute pressure at 20 °C [68 °F]	4 ...20mA
0 …3(18.65) [0 ... 43.51]
0 ... 6 (38.87) [0 ... 87.02]
0 …8(53.4) [0 ... 116.03]
0 …10(68.96) [0 ... 145.03]
0 …12(85.79) [0 ... 174.04]
0 …16(124.64) [0 ... 232.06]

Density range in g/l SF 6 (compensated pressure range in bar abs. at 20 °C [psi abs. at 68 °F])	Accuracy 1)	Output parameters	Output signal
0 …10(1.64) [0 ... 145.03]	■ ±2% ■ ±1.5%	SF₆ gas density in g/l	4 ...20mA
0 …16(2.59) [0 ... 232.06]
0 ... 25 (3.97) [0 ... 362.59]
0 …40(6.16) [0 ... 580.15]
0 …60(8.87) [0 ... 870.22]
0 …80(11.33) [0 ... 1,160.3]

Compensated pressure range in bar abs. at 20 °C [psi abs. at 68 °F] (g/l SF₆)	Overload safety in bar abs. [psi abs.]	Burst pressure in bar abs. [psi abs.]
0 ... 2 (12.28) [0 ... 29.00]	6.2 [89.92]	10 [145.03]
0 ... 3 (18.65) [0 ... 43.51]	14.5 [210.30]	24 [348.09]
0 ... 6 (38.87) [0 ... 87.02]	14.5 [210.30]	24 [348.09]
0 ... 8 (53.4) [0 ... 116.03]	31 [449.61]	52 [754.19]
0 ... 10 (68.96) [0 ... 145.03]	31 [449.61]	52 [754.19]
0 ... 12 (85.79) [0 ... 174.04]	31 [449.61]	52 [754.19]
0 ... 16 (124.64) [0 ... 232.06]	62 [899.23]	103 [1,493.89]

Case

Case material	316L
Case options	■ Cable outlet ■ Metal cable outlet, shield optionally connected (heavy-duty version)

Name in accordance with IUPAC 2) nomenclature	Abbreviation	Description (CAS no.)
Sulphur hexafluoride	SF 6	2551-62-4
Nitrogen	N 2	7727-37-9
Tetrafluoromethane	CF 4	75-73-0
Oxygen 3)	O 2	7782-44-7
Carbon dioxide	CO 2	124-38-9
2,3,3,3-Tetrafluoro-2-(trifluoromethyl)propanenitrile 4)	C4-FN (fluoronitrile)	42532-60-5
Helium	He	7440-59-7
Argon	Ar	7440-37-1