Honeywell VCM DATASHEET
Pressure switches
Mechanical 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
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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 pressure 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 counterforce 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 bellows, 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 stainless 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 connected 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
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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 figure can serve only as a rough estimate. With pulsating pressure or pressure impacts in hydraulic systems, 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 greasefree. The sensors are hermetically encapsulated. They contain no seals. (See also additional function
ZF 1979 Special Packing)
Switch housing
Pressure connection
Switching function and connection 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 switching 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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