AD-FM 255 GVD, AD-FM 255 GVD-O


The frequency measuring converter AD-FM 255 GVD supplies an initiator or a contact and transforms its impulse sequence to a proportional impressed analogue signal. The output signal is independent from the connected load up to a maximum value. All measuring ranges and outputs can be freely parameterized. This can be carried out via the optional operating panel AD-VarioControl or via the programming software AD-Studio. Input, output and the supply voltage are separated from each other galvanically with high isolation.

AD-FM 255 GVD, AD-FM 255 GVD-O


The main area of application is the through-flow measuring at water meters, further applications are energy consumption measuring etc.

Specific characteristics

  • Inputs: NAMUR, contact, open collector, 3-conductor Opto, 24V activ
  • Outputs: current and voltage
  • Digital output: Relay or semiconductor (pulse or limit value function)
  • Operating module VarioControl as an accessory
  • Programming via configuration software

Business data

Order number
AD-FM 255 GVD Relay output
AD-FM 255 GVD-O Semiconductor output
Accessory (optional)
Operating module AD-VarioControl
USB programming adapter AD-VarioPass /AD-Studio
EClass 27210128
Customs tariff number / country of origin 8543 70 90 / Deutschland


Technical specifications

Digital input
Input NAMUR (EN 60947-5-6), reed contact, open-collector, 3-lead opto-transmitteror 24V active
Input frequency Min. 0 ... 10 mHz; max. 0 ... 10 kHz
Frequency generator supply Active: 8V / 8mA
Kontaktentprellung (activatable) 40 ms
Output current
Output range 0 ... 20 mA
Max. burden 400 Ohm
Residual ripple < 50 µAss
Output voltage
Output range 0 ... 10 V
Min. burden 10 kOhm
Residual ripple <20 µVss
Unit <0,3%
Temperature influence <100 ppm / K
Response time Approx. 70 ms
Relay output
Contact type Potential-free changeover
Max. AC-breaking capacity 250 V AC, 2 A AC, 50Hz
Max. DC-breaking capacity 50 V DC, 2 A DC
Switching operations
Mechanical 107
AC: 230V / 2A, cos(phi)=1 6 * 105
AC: 230V / 2A, cos(phi)=0,4 2 * 105
DC: 24V / 1A 2 * 105
Semiconductor output (optional)
Max switching voltage 30 V DC
Max. switching current 50 mA DC
Voltage drop < 1 V
Voltage range AC 50 ... 253 V AC, 50/60 Hz
Nominal voltage AC 230 V AC
Voltage range DC 20 ... 253 V DC
Nominal voltage DC 24 V DC
Power consumption AC / DC 3,7 VA / 2,1 W
Dimensions (WxHxD) 23x110x134 mm
With operating module (bxhxt) 23x110x138 mm
Type of protection IP 20
Connection method Detachable terminal clamp
Terminals, wire cross section 2,5 mm² flex wire / 4 mm² one wire
Bolting torque terminals 0,5 Nm
Weight ~ 140 g
Manner of fastening 35 mm DIN rail 35mm
Environmental conditions
Ambient temperature -10 ... 50 °C
Storage and transport -10 ... 70 °C (no condensation)
Product family standard 1) EN 61326-1
Emitted interference EN 55011, CISPR11 Cl. B, Gr. 1
In a critical EMC environment, shielded encoder cables are recommended.
1)During electromagnetic disturbance minor changes in output signal are possible.
Electrical safety requirements
Product family standard EN 61010-1
Overvoltage category II
Pollution degree 2
Galvanic isolation, test voltages
Input/output 2 kV RMS (1 min.)
Signal/auxiliary voltage 3 kV RMS (1 min.)

Block and wiring diagram

AD-FM 255 GVD, AD-FM 255 GVD-O


AD-FM 255 GVD, AD-FM 255 GVD-O

We only use technically necessary cookies to improve the user-friendliness of our site.
Cookies for analysis and marketing purposes are not used!
You can find further information in our privacy policy.
made with ♡ by