The supply-limit-switch AD-SMK 330 GS serves the switching of limiting values on transmitter signals. The device has an 0..20 mA, 4..20 mA input and an 0..10 V input and a current-limited transmitter feed. With this, 2-wire and 3-wire transmitter can be supplied and measured. With its two potential-free change-over contacts, the AD-SMK 330 GS can switch maximal two independent limiting values. The switching thresholds can be set at the front with the aid of the integral key coding switch in percent steps. The status of the relevant relay is indicated via an LED at the front. The AD-SMK 330 GS has two different operating modes, which can be selected via the function keys. Either two independent limiting values can be switched, whereby here one key coding switch per relay is effective. The switching hysteresis is in this case 1 percent. In operating mode hysteresis, both relays are synchronous. Here, the upper and lower switching point (switch-on point and switch-off point) can be selected separately with the two key coding switches. The relays can work in the operating current principle or the closed-circuit current principle in both operating modes. This can also be selected at the function keys. The efficient wide range power pack allows the supply with all established supply networks or voltage levels. Input, output and supply voltage are separated from each other galvanically with high isolation.



Switching of limiting values on active standard signals, which correspond to, for instance, flows, height levels or temperatures.

Specific characteristics

  • analog inputs for current and voltage
  • current limited transmitter supply
  • two potential-free changeover
  • simple point setting using coded key
  • wide range power supply

Business data

Order number
Customs tariff number / country of origin 8538 90 91 / Deutschland


Data sheet pdf en-smk330gs.pdf (272 kB)
Tender text zip (14 kB)
Safety instructions pdf ad-safety-instructions.pdf (43 kB)

Technical specifications

Current inputs
Measuring range 4 ... 20 mA
Input resistance 50 Ohm
Input voltage
Measuring range 0 ... 10 V
Input resistance 400 kOhm
Transmitter supply
Voltage open circuit/full load Less then 21 V / higher 18 V
Current limit Ca. 30 mA
Relay outputs A/B
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
Transmission behaviour
Basic accuracy 1 % (1 Digit)
Temperature influence +/- 100 ppm/K of full scale
Response time 100 ms
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 2,4 VA / 1,8 W
Manner of fastening DIN rail 35mm (EN 50022)
Type of protection IP 20
Connector cross section Max. 2,5 mm²
Weight ~ 200 g
Environmental conditions
Ambient temperature -10 ... 50 °C
Storage and transport -10 ... 60 °C (no condensation)
Product family standard 1) EN 61326-1
Emitted interference EN 55011, CISPR11 Cl. B, Gr. 1
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/relays 4 kV (1 min)
Input/power-supply 3 kV (1 min)
Relays/power supply 4 kV (1 min)
Relays with each other 3 kV (1 min)
Protective systems
Input Overvoltage
Power supply Over voltage, over current and over temperature

Block and wiring diagram




Circuit examples


CAD / CAE Daten

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