GDM-100-T

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WIKA · SF6 gas solutions · Family GDM

Hybrid gas density monitor

Name: Hybrid gas density monitor
Brand: WIKA

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

Range

0…21.3 bar

Output

4 ... 20 mA · Modbus® RTU

Accuracy

±1 % at 20 °C

Protection

IP65

RoHSCEEMC directive EN 61326EMC

Price

On request

Depends on configuration

Request a quote

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Description

Gas density is a crucial operating parameter for high-voltage plants. 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-100-T high-precision sensors and evaluation electronics are incorporated.

Via the on-site display, 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 4 ... 20 mA or Modbus ® sensors integrated or attached to the instrument enable remote monitoring of the plant.

Left: Hybrid gas density monitor with integrated transmitter, model GDM-100-T

Right: Hybrid gas density monitor with attached transmitter, model GDM-100-T

The measured data for pressure, temperature and gas density are transmitted using the standardised Modbus ® RTU protocol. The model GDM-100-T can also be configured for alternative gases consisting of N₂, CF₄, O₂, CO₂, 3M™, Novec™ 4710, He and Ar.

The analogue version of the GDM-100-T uses the proven technology of the 4 ... 20 mA analogue signal and outputs the absolute pressure at 20 °C [68 °F] or the gas density in g/l for SF₆ gas as an analogue signal.

The data storage enables trend analysis to be carried out, so that critical SF6 gas conditions can be predicted and rectified in time. An optimisation of the maintenance strategy from time-based (TBM) to condition-based (CBM) is possible through the use of the gas density monitor.

Special features

Ideally suited for smart grid or modernisation projects
Modbus ® delivers measured values for pressure, temperature and gas density as 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 for SF 6 gas
Compact design with only one process connection
Suitable for alternative gases

Identification

Model	GDM-100-T
Product family	GDM
Subcategory	Hybrid gas density monitor with integrated/attached transmitter

Measuring range

Pressure ranges	1.6…16 bar · 0…2.4 bar · 0…3.7 bar · 0…7.5 bar · 0…10.1 bar · 0…12.9 bar · 0…15.7 bar · 0…21.3 bar · 0…2 bar · 0…3 bar · 0…6 bar · 0…8 bar · 0…10 bar · 0…12 bar · 0…16 bar
Density reference temperature	20 °C

Accuracy

Accuracy class

±1 % at 20 °C, ±2.5 % from -20 ... +60 °C

Process conditions

Process connection

G 1/2 B per EN 837G 1/2 B

Electrical characteristics

Output signal	4 ... 20 mA · Modbus® RTU · Modbus RTU
Switching contacts	3

Materials

Wetted parts material

Stainless steel

Operating environment

Ambient temperature	−20…+60 °C
IP rating	IP65
Weight	1.4 kg

Certifications and approvals

Certifications

RoHSCEEMC directive EN 61326EMC

Additional details

Temperature compensation	Yes
Datasheet languages	EN

Tables from datasheet

Selectable versions

Option 1	Laminated safety glass
Option 2	Acrylic glass

Selectable versions

Option 1	1 magnetic snap-action contact
Option 2	2 magnetic snap-action contacts
Option 3	3 magnetic snap-action contacts

Selectable versions

Option 1	Falling pressure
Option 2	Rising pressure

Selectable versions

Option 1	Normally closed
Option 2	Normally open

View all (20)

Selectable versions

Option 1	Galvanically connected
Option 2	Galvanically isolated

Compensated pressure in bar abs. at 20 °C [68 °F] (g/l SF₆)	Pressure in bar abs.	Temperature	Output parameters	Output signal
0 …2(12.28)	0 …2.4	-40 …+80 °C [-40 ...+176 °F]	■ Density ■ Pressure at 20 °C [68 °F] ■ Pressure ■ Temperature	Modbus ® RTU
0 …3(18.65)	0 …3.7
0 ... 6 (38.87)	0 ... 7.5
0 …8(53.4)	0 …10.1
0 …10(68.96)	0 …12.9
0 …12(85.79)	0 …15.7
0 …16(124.64)	0 …21.3

Accuracy specifications

Accuracy 1)
Compensated pressure ranges in bar abs. at 20 °C [68 °F] (g/l SF₆) 0 …2(12.28) 0 ... 6 (38.87) 0 …3(18.65)	For -40 ... -20 °C [-40 ... -4 °F]	■ ±2 %(standard) ■ ±1.5 %(option)
Compensated pressure ranges in bar abs. at 20 °C [68 °F] (g/l SF₆) 0 …8(53.4) 0 …10(68.96) 0 …12(85.79)	For -20 ...+80 °C [-4 ...+176 °F]	■ ±1.25 %(standard) ■ ±0.75 %(option)
0 …16(124.64)	For -40 ...+80 °C [-40 ...+176 °F]	■ ±1.25 %(standard) ■ ±0.6 %(option)
Pressure accuracy	■ ±1 %at 20 °C [68 °F] (standard) ■ ±0.2 %at 20 °C [68 °F] (option)
Temperature accuracy	±1.5 K
Reference conditions	Per IEC 61298-1

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

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

Compensated pressure range in bar abs. at 20 °C [68 °F] (g/l SF₆)	Overload safety in bar abs.	Burst pressure in bar abs.
0 ... 2 (12.28)	6.2	10
0 ... 3 (18.65)	14.5	24
0 ... 6 (38.87)	14.5	24
0 ... 8 (53.4)	31	52
0 ... 10 (68.96)	31	52
0 ... 12 (85.79)	31	52
0 ... 16 (124.64)	62	103

Case

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

Output signal

Voltage supply	DC10…30V
Power consumption
Model GD-20-A	≤ 0.75W
Model GD-20-D	≤ 0.45W
Maximum permissible load R A (model GD-20-A)	R A ≤ (U B - 9.5 V) / 0.023 A with R A in ohm and U B inV
Time response
Settling time 1)	< 10 ms
Switch-on time 2)	≤ 500 ms

Rear cable socket

1	-	-
2	U +	DC 10 ...30V
3	U -	Mass
4	A	RS-485 signal
5	B	RS-485 signal
6	-	-

Rear cable socket

1	U +	DC 10 ...30V
2	-	-
3	U -	Mass
4	-	-
5	-	-
6	-	-

Operating conditions

Electrical safety
Model GD-20-D	Reverse polarity voltage U + vs.U -
Model GD-20-A	Reverse polarity voltage U + vs.U -

EMC tests

Immunity to EMF	30 V/m (at 80 MHz to 6 GHz)
Immunity against surge voltages (surge) per IEC 61000-4-5	1 kV, non-symmetrical, cables to ground, RS485A to RS485B, U + vs.U -
ESD per IEC 61000-4-2	8 kV contact discharge, 15 kV indirect discharge, 8 kV indirect discharge
Immunity against conducted HF signals in accordance with IEC 61000-4-6	10V at 150 kHz to 80 MHz
Immunity against fast transients (burst) per IEC 61000-4-4	4 kV

Logo	Description	Country
	EU declaration of conformity	European Union

Designation	Case ingress protection	Temperature range in	°C Shield provided customer	Shield connected on the instrument	Assignment
				side	U +	U -
Cable outlet 2 m, plastic	IP67	-40 ...+80 °C [-40 ...+176 °F]	Yes	-	Brown	Blue
Cable outlet 5 m, plastic			Yes	-
Cable outlet 10 m, plastic			Yes	-
Cable outlet 2 m, SS			Yes	-
Cable outlet 5 m, SS			Yes	-
Cable outlet 10 m, SS			Yes	-
Cable outlet 2 m, shield connected, SS			Yes	Yes
Cable outlet 5 m, shield connected, SS			Yes	Yes
Cable outlet 10 m, shield connected, SS			Yes	Yes

Model	Description	Order number
Modbus ® start-up kit	■ Power supply unit for sensor ■ Connection cable ■ Interface converter (RS-485 to USB) ■ USB cable type A to type B ■ Modbus ® tool software on USB stick	14075896
WIKAsoft-GD for configuration and testing of the digital sensor	Free download from: www.wika.com/download	-
Optional accessories
Recalibration valve	Model GLTC-CV ■ Enables easy recalibration of the gas density monitor without dismounting ■ Welded permanently to the instrument or available as loose valve for retrofitting	-
Connection cable for Switching outputs	■ Terminal without wiring ■ Connector mounted on the instrument side, cable with loose ends	-

Description	Order number
Adapter from test connection (M26 x 1.5) to quick coupling	14146937
Protective cap for test connection (M26 x 1.5)	14193772
Calibration system for SF₆ gas density measuring instruments, model BCS-10	SeeWIKA data sheet SP 60.08
Calibration system for SF₆ gas density measuring instruments, model ACS-10	SeeWIKA data sheet SP 60.15