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 the
Drive
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.
