Honeywell VCM DATASHEET

Pressure switches

Mechanical pressure switches

Technical features / Advantages

Wall mounting

or directly on the pressure line

Switching element (microswitch)

Lead sealable setpoint adjustment

Setting spindle locking element

Terminal connection

or plug connection to

DIN 43 650 Form A

Stainless steel sensor housing

Stainless steel bellows

with internal stop

Pressure connection

G 1/2“ external

G 1/4” internal

Centring pin

Diecast aluminium housing

IP 54 or IP 65

version also available

Pressure switches

Mechanical pressure switches

Pressure switches

General description

Operating mode

The pressure occurring in the sensor housing (1) acts on the measuring bellows (2). Changes in pres-

sure lead to movements of the measuring bellows (2) which are transmitted via a thrust pin (4) to the

connecting bridge (5). The connecting bridge is frictionlessly mounted on hardened points (6). When the

pressure rises the connecting bridge (5) moves upwards and operates the microswitch (7). A counter-

force is provided by the spring (8) whose pretension can be modified by the adjusting screw (9)

(switching point adjustment). Turning the setting spindle (9) moves the running nut (10) and modifies

the pretension of the spring (8). The screw (11) is used to calibrate the microswitch in the factory. The

counter-pressure spring (12) ensures stable switching behaviour, even at low setting values.

Pressure sensors

Apart from a few exceptions in the low-pressure range, all pressure sensors have measuring bellows,

some made of copper alloy, but the majority of high-quality stainless steel. Measured on the basis of

permitted values, the measuring bellows are exposed to a minimal load and perform only a small lifting

movement. This results in a long service life with little switching point drift and high operating reliability.

Furthermore, the stroke of the bellows is limited by an internal stop so that the forces resulting from

the overpressure cannot be transmitted to the switching device. The parts of the sensor in contact

with the medium are welded together without filler metals. The sensors contain no seals. Copper bel-

lows, which are used only for low pressure ranges, are soldered to the sensor housing. The sensor

housing and all parts of the sensor in contact with the medium can also be made entirely from stain-

less steel 1.4571 (DNS series). Precise material data can be found in the individual data sheets.

Pressure connection

The pressure connection on all pressure switches is executed in accordance with DIN 16288 (pressure

gauge connection G 1/2A). If desired, the connection can also be made with a G 1/4 internal thread

according to ISO 228 Part 1. Maximum screw-in depth on the G 1/4 internal thread = 9 mm.

Centring pin

In the case of connection to the G 1/2 external thread with seal in the thread (i.e. without the usual

sheet gasket on the pressure gauge connection), the accompanying centring pin is not needed.

Differential pressure switches have 2 pressure connections (max. and min.) each of which are connect-

ed to a G 1/4 internal thread.

1 = Pressure connection

2 = Measuring bellows

3 = Sensor housing

4 = Thrust pin

5 = Connecting bridge

6 = Pivot points

7 = Microswitch or other switch-

ing elements

8 = Setting spring

9 = Setting spindle (switching

point adjustment)

10 = Running nut (switching point

indicator)

11 = Microswitch calibration

screw (factory calibration)

12 = Counter pressure spring

General technical data

Diecast aluminium GD AI Si 12 Diecast aluminium GD AI Si 12

G 1/2 external thread (pressure gauge connection) and G 1/4 internal thread

G 1/4 internal thread for DDCM differential pressure switches

Floating changeover contact. Floating changeover contact.

With rising pressure switching With rising pressure switching

single-pole from 3-1 to 3-2. single-pole from 3-1 to 3-2.

8 A at 250 VAC 3 A at 250 VAC

5 A at 250 VAC inductive 2 A at 250 VAC inductive

8 A at 24 VDC 3 A at 24 VDC

0.3 A at 250 VDC 0.03 A at 250 VDC

min. 10 mA, 12 VDC min. 2 mA, 24 V DC

preferably vertical vertical

(see technical data sheet)

IP 54; (for terminal connection …300 IP 65) IP 65

– EEx de IIC T6 tested to EN

50014/50018/50019 (CENELEC)

– PTB 02 ATEX 1121

Plug connection to DIN 43 650 (200 series) Terminal connection

or terminal connection (300 series)

PG 11 / for terminal connection M 16 x 1.5 M 16 x 1.5

See data sheets –15 to +60°C

Adjustable via spindle. On switching device Adjustable via spindle after the

300 the terminal box cover must be removed terminal box lid is removed

Adjustable or not adjustable Not adjustable

(see Product Summary)

Only possible on plug connection housing 200

Max. 70°C, briefly 85°C Max. 60°C

Higher medium temperatures are possible provided the above limits for the switching device are

ensured by suitable measures (e.g. siphon).

All pressure switches can operate under vacuum. This will not damage the device.

< 1% of the working range (for pressure ranges > 1 bar)

No significant deviations up to 4 g.

With sinusoidal pressure application and room temperature, 10 x 106 switching cycles.

The expected life depends to a very large extent on the type of pressure application, therefore this fig-

ure can serve only as a rough estimate. With pulsating pressure or pressure impacts in hydraulic sys-

tems, pressure surge reduction is recommended.

Overvoltage category III, contamination class 3, reference surge voltage 4000 V.

Conformity to DIN VDE 0110 (01.89) is confirmed.

The parts of all pressure switches with sensors made from steel or stainless steel are oil and grease-

free. The sensors are hermetically encapsulated. They contain no seals. (See also additional function

ZF 1979 Special Packing)

Switch housing

Pressure connection

Switching function and con-

nection diagram

(applies only to version with

microswitch)

Switching capacity

(applies only to version with

microswitch)

Mounting position

Degree of protection (in vertical

position)

Ex degree of protection

PTB approval Electrical connection

Cable entry

Ambient temperature

Switching point

Switching differential

Lead seal

Medium temperature

Vacuum

Repetition accuracy of switch-

ing points

Vibration strength

Mechanical life

Isolation values

Oil and grease-free

Normal version

Plug connection Terminal connection

…200 …300

version

…700

with microswitches of the DCM, VCM, DNM, DNS and DDC series.

The technical data of type-tested units may differ slightly.

(please refer to type sheet)

Pressure switches

Mechanical pressure switches

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