SD7540A Stepper Drive
20 Gear Drive, Plymouth Industrial Park, Terryville, CT 06786
page: 12
Tel: (860) 585-1254 Fax: (860) 584-1973 Web: www.amci.com
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MIC RO CON T RO L S INC.
Wiring the SD7540A Control Signals to a Single-Ended Input
The SD7540A is built with differential inputs for optimal noise immunity. However many stepper
control circuits use single-ended (sinking or sourcing) control signals. The following schematics
show the correct wiring when using the SD7540A with single-ended control signals.
V
D C
R
L I M I T
5 V o l t s
1 2 V o l t s
1 5 V o l t s
2 4 V o l t s
N o n e
2 . 0 K
9
2 . 0 K
9
3 . 9 K
9
S D
I n p u t
+ S T E P
O R
+ D I R E C T I O N
S T E P
O R
D I R E C T I O N
R
L I M
I n d e x e r
O u t p u t
V
D C
+ 5 t o + 2 4 V
S D
I n p u t
+ S T E P
O R
+ D I R E C T I O N
S T E P
O R
D I R E C T I O N
R
L I M
V
D C
+ 5 t o + 2 4 V
O p e n C o l l e c t o r S o u r c i n g O u t p u t
O p e n C o l l e c t o r S i n k i n g O u t p u t
I n d e x e r
O u t p u t
S h i e l d e d , T w i s t e d
P a i r C a b l e
S h i e l d e d , T w i s t e d
P a i r C a b l e
Note: For the Disable input, the internal resistor is 1 k
Ω
. For the Step and Direction inputs,
the internal resistor is 316
Ω
Disable Input Wiring
The Disable Input on the SD7540A will shut off motor current when active. With the exception of
the internal resistor value, the circuitry of the Disable Input is identical to the Step and Direction
Inputs.
The SD7540A does not accept directional pulses while the Disable Input is active.
If not used, the Disable Input pins can be left open. The SD7540A will never disable the motor
current if these pins are left open.
