10 HD65 & HD130 STEPPER DRIVES USER GUIDE
operation provided the speed is less than about 440 half steps/sec.
This speed is programmable (see "Setting up the drive"). Switch 6
may be turned on to hold this input permanently at 0v and so prevent
the anti-resonance system from operating.
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PIN 14 - Square-off. When this input is open-circuit, the motor
current is "squared off" to the one-phase-on level at approximately
3200 half steps/sec. This gives improved midrange torque
compared with the usual two-level current profile. However the input
may be taken to 0v which will cause the drive to square off
permanently. Square-off can also be disabled (see programming
switch 0 under "Setting Up the Drive").
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PIN 15 - External Reset. Connect to 0v to reset a fault condition
(provided the cause of the fault has been removed). An alternative
method of resetting is to temporarily remove power.
PIN 16. Sync. Connecting the sync terminals of several drives
together will cause all the chopper regulators to synchronise,
eliminating beat fre-quencies and minimising the audible noise at
standstill. Turret lugs are provided on each side of the motherboard
to simplify interconnection between adjacent drives. All drives in a
single rack may be interconnected in this way, but it is not
recommended to connect drives in different racks together.
Setting Up theDrive
Motherboard Link The two-position link on the motherboard is fitted in position "a" for a
standard drive operating in the full or half step mode. Position "b" is
used when the optional microstep card is fitted.
A 10-position programming switch on the motherboard sets up the
main operating conditions, and in most applications this will be the
only adjustment required. Certain parameters are determined by
resistors on the drive and on the motherboard, and again the values
as supplied have been optimised for all normal applications.
Information is given on changing these parameters should this prove
necessary.
The functions of the programming switch are as follows:
1-4: Current programming. (see next section).
5: Square-off switch. Turning this switch "on" has the same
effect as grounding the "square-off" terminal, i.e. gives
permanent square-off at the one-phase-on current except at
standby.