RMS Technologies 4-AXIS CONTROLLER/DRIVER - Manual (Page 11)

S I X P A C K / Q U A D P A C K 11
5 S Y S T E M S T A R T U P
5.1 System Start Up / Notes
When the PACK is supplied with power it runs an internal initialization and a self-test of the internal
processor-system starts. If executed successfully a “0“ appears in the LED-display after a second. The
PACK is operational now and can receive user commands.
Defective motor drivers can not be detected by the self test. Should the motor turn on and off during
operation, a constant high motor current or insufficient cooling of the drivers could be the problem. The
motor driver chip turns itself off for a short time when overheated. To allow higher constant motor current
the motor drivers of the PACKs are cooled with a heat sink. A forced air cooling can additionally improve
the maximum current.
When an application requires detection of temporarily interrupted power supply of the PACK, this can be
done for example by signaling via external TTLOUT1 by programming it to a negative level. The RS 232-
interface usually receives a 0-byte after hardware reset.
5.2 Selecting Motors
When selecting motors, consider stepper motors with the lowest inductance possible, i.e. low coil
resistance, to obtain smoothest movements and the maximum possible rpm. On the other hand low coil
resistance lowers the torque. Therefore you should choose the motor with the lowest inductance
possible which delivers the needed torque at a coil current of approx. 600 mA respectively 1000mA.
Highest possible operating voltage of the PACK results in high rpm also. With higher coil resistance or a
too low operating voltage the duty factor of the chopper drivers increases. When exceeding 50% a
cheering noise can occur in the coils.
5.3 Length of Wires
motor wires: must be < 3m (use twisted pair wire)
RS 232: must be <3m
CAN, RS485: can be >30m
5.4 Cooling
If the continuous current for drive and stop is higher than 1A with QUADpacks or higher than 500 mA
with SIXpacks, the PCBs must be cooled sufficiently.
This can be achieved by mounting the PACK vertically, so that the motor supplies are located on top.
With continuous full load cooling will be required.
5.5 Grounding
For a good ESD protection the electronics must be connected effectively with ground. Therefore two
holes are provided on the PCB with ground contacts.
If the electronics is delivered without housing, these two screws must be connected to ground.
If the electronics are built-in the housing the tape must be taken away of the two fixing drilled holes on
the back side. The electronics must now be grounded via these two blank areas.
5.6 Improvement of the EMC-Conduction
To improve the cable-bound conducted emission, a ferrite-clip should be clipped over the supply circuit.