SM2910 / SM2930 Servomotor

The SM2910 / SM2930 Servomotor is unique in that it is both an ON/OFF and PROPORTIONAL motor in one. Either mode is selectable from DIP switch 2 and the input circuitry is protected so that even if the DIP switch is set to PROP mode (0 - 10VDC) and 24VAC is applied, there can be no damage. The Status LED would flash five times to indicate the DIP switch is incorrectly set. The Servomotor can also be set for two speeds via DIP switch 4, 20 seconds for high speed operation and 60 seconds for normal operation over 90°. The microprocessor controller also controls the speed of the motor so that it is constant regardless of load.

The Servomotor direction can be reversed by DIP switch 1 either ClockWise (CW) or Counter ClockWise (CCW). There is also a soft start feature so that whenever the motor starts the microprocessor controller ramps it up to full speed. It also stops the Servomotor instantly so there is no overshoot. This enables the Servomotor to have a very narrow deadband of 0.1V. In practical terms, with a 0 - 10VDC input range and a 1VDC input, the motor would start at 0.1VDC and stop at 10% open. With the input signal falling to 0VDC the motor would reverse at 0.9VDC and drive back to fully closed. Another unique feature of the Servomotor is the self centring damper clamp which enables the Servomotor to be bolted directly to the mounting surface, as it does not suffer from the oscillating motion of the U - clamp type damper motors. When actuators are used on rising stem valves they are generally limited to 90° rotation. However this requires a different rack and pinion assembly with a larger pinion for increased travel. This reduces the output thrust or force, necessitating a more powerful actuator. The SM2910 / SM2930 Servomotor is selectable for either 90° or 270° rotation on the CW Pot and uses the same rack and pinion assembly for small and large valves.This means that the SM2910 15Nm Servomotor is all that is required for most applications. Used in these applications the Servomotor will self-stroke (torque limit), simplifying set-up and commissioning. The microprocessor controller will hold the torque limit for five seconds and then shut off. The status LED will flash once every second to indicate the Servomotor is in torque limit.

The SM2910 (15Nm) / SM2930 (30Nm) Servomotor has a built-in torque limit which protects the geartrain and external equipment Most other actuators rely on this torque limit to end stop or reduce the rotational angle through mechanical stops on or external to the actuator. With the SM2910/SM2930 Servomotor, two electronic limit potentiometers are provided. The first with a rotational adjustment of 0 - 45° and the second with a rotational adjustment of 45 - 90° and 270°.

The 0 - 10VDC Proportional mode is also fully adjustable with a Zero adjustment of 0 - 9VDC and a Span adjustment of 1 - 10VDC. The scales are both 0 - 10VDC for ease of setting. If the Zero pot is set at 10V the maximum offset will still be 9VDC and if the Span pot is set at OV the minimum span will still be 1VDC. The default settings are: Zero - OVDC and Span - 10VDC. When operation under power fail mode is required, the usual method has been to use a mechanical spring, which is wound up as the actuator drives. The disadvantages with spring return have been the heavy load constantly imposed upon the motor and geartrain winding the spring up and down and the reduction in output torque available, which also reduces proportionally as the spring winds down. EG: if a spring return actuator has an output torque of 10Nm when fully wound up, it will only have about 3Nm when wound down.

The SM2910/SM2930 Servomotor range can be fitted with a unique Power Fail Module (PFM) which mounts in the cover of the Servomotor and plugs into the main board. The PFM consists of a number of SuperCaps (Capacitors) depending upon the torque required and associated electronics. This module supplies a constant output voltage and hence a constant speed. When power is applied the Servomotor will drive open and the PFM will be charged at the same time. When power is removed the Servomotor will drive back with full torque and high speed taking only 15 seconds for 90° rotation. The direction the Servomotor has to drive under power fail mode is selectable from DIP switch 3, alleviating the need to remove the actuator from the damper shaft, reverse it and replace it on the shaft.

An auxiliary switch module (ASM292) is available for the Servomotor and plugs onto the main board. This has two switches that are adjustable over the full operating range of 90° or 270° via two potentiometers. The auxiliary switches are rated at 250VAC 5A.

Note:Off is default

SWITCH ON OFF
1 COUNTER CLOCKWISE (CCW) CLOCKWISE (CW)
2 PROPORTIONAL 0 - 10 VDC ON / OFF
3 POWER FAIL CLOCKWISE (PFCW) POWER FAIL COUNTER CLOCKWISE (PFCCW)
4 20 SEC 60 SEC

FULL ON
ONE FLASH EVERY SECOND
FIVE FLASHES EVERY 15 SECONDS SET

NORMAL OPERATION
TORQUE LIMIT OR SELF STROKING FUNCTION
DIP SWITCH 2 INCORRECTLY

SUPPLYVOLTS 24VAC
50/60Hz Nominal 24VDC Nominal
MIN 17 VAC MAX 29VAC MIN 20VDC MAX 36VDC

POWER FOR TRANSFORMER SIZING
T2,7W 5VA - SM2910
3,7W - SM2930 7VA

INPUT SIGNAL
0 - 10 VDC
Proportional Mode Only

INPUT IMPEDIENCE
100KΩ (effective)
Proportional Mode Only

ZERO ADJUST
0 - 9 VDC
Proportional Mode Only

DEFAULT SETTINGS
ZERO - 0 VDC
SPAN - 10VDC

ROTATIONAL ANGLE
90° and 270° via CW pot
90° and 270° via CW pot

ROTATIONAL ADJUST
CCW 0 - 45°
CW 45° - 90° and 270°

ROTATIONAL TIME
90° - 20 or 60 sec (SW4) or 15 sec PFM
270° - 60 or 180 sec (SW4) or 45 sec PFM

ROTATIONAL DIRECTION
Reversible via DIP SW1
Reversible via DIP SW1

OUTPUT TORQUE
SM2910 - 15Nm
SM2930 - 30Nm

PROTECTION
IP52
IP52

TEMPERATURE RANGE
-10 to 50°C
-10 to 50°C

WEIGHT
SM2910 - 750g
SM2930 - 950g

MATERIAL - HOUSING
Case - Polycarbonate
Lid - polypropylene

MATERIAL - GEARS
SM2910 - Acetal
SM2930 - Acetal & Metal