EM-121 STEPPER MOTOR CONTROLLER 40V 1A FEATURES • Bipolar chopper • Wide operating voltage range • Full and half step operation • 7-settable phase currents • Auxiliary oscillator • Acceleration ramp, 3-speed • Self recovery fuse • Rail mounting base fittable EM-121 is bipolar-chopper type stepper motor controller. Bipolar operation suits most stepper motors and provides the best torque. Phase current is set to desired level using chopping type current limit. The phase current ( current limit ) can be set in seven different levels using jumpers. A wide phase current set range makes it possible to use the device with several different motors. EM-M121 also utilizes steady state current hold, in other words when the motor is stopped the controller decreases phase current, this feature reduces both the motor and controller thermal loss. Two steady state current hold modes are settable. The controller features an auxiliary oscillator, which has fifteen preprogrammed frequencies. The frequency is set with four control inputs. Auxililary oscillator in EM-121 has also an acceleration ramp feature, which can be used to change frequencies flexibly, so that the motor will start up reliably even at high frequencies. There are three acceleration ramp intervals, that can also be bypassed. The inputs operate with so called negative logic, in other words the inputs are activated with connecting the input to ground, the inputs also work with TTL-logic level control. The power state of EM-121 has thermal protection for overload, the device has also self recovery fuse that protects the controller from over current and reversed input voltage polarity. EM-121 BLOCK DIAGRAM TECHNICAL DATA: 1A PTC FUSE Operating voltage Idle current Current set Steady state I hold Voltage loss Fuse Aux. osc. freq. Freq. precision Digital control Step freq. Operating temp. Dimensions Weight 12-40Vdc approx. 40mA / (20mA shutdown "0") 0.25; 0.37; 0.5; 0.63; 0.75; 0.9; and 1.0A approx. 35 or 67% of current set 3V when Im=1A 1A self recovery. 20, 50, 100, 200, 300 Hz 400, 600, 800, 1000 Hz 1.5; 2; 2.5; 3; 3.5; 4 kHz typ. 1% "off" when Uin 4 -30V or open "on" when Uin 0-1V max. 9kHz 0-50°C 67x75x25mm approx. 100g 15 + 6 INPUT REGULATION 14 5 FULL- / HALF STEP 11 SHUTDOWN 13 DIRECTION 12 STEP 1 STEP LOGIC 2 POWER STAGE STEADY STAGE CURRENT HOLD 3 CURRENT LIMIT 10 9 AUX OSCILLATOR 4 8 7 ACCELERATION RAMP PHASE CURRENT SM

speed 4 speed 3 speed 2 speed 1 shutdown step input Supply voltage 12-40Vdc filtered. direction 0V gnd full / half OPERATING INSTRUCTIONS EM-121 Control inputs are activated using switches, or 0-5V voltage signals, or NPN-open collector outputs. 10 11 12 13 14 15 67mm 72mm ramp A A' 2 3 4 5 B B' 1A 0.9A 6 supply 12-42V 1 supply 0V current set CURRENT SET Phase current setting map 9 steady state current hold 8 STEP: - full step switch on or 0V half step switch off or 5V DIRECTION: - Forward switch on or 0V Backwards switch off or 5V STEP-INPUT: - TTL or 0-5V pulse, trigs with falling edge SHUTDOWN:...