INSTALLATION
15
CURRENT SET
TERMINAL 11 & 12
The CURRENT SET input determines the magnitude of the motor phase currents. This
is done by connecting a
1
⁄
4
watt resistor between Terminals 11 & 12. Terminal 11 is
the CURRENT SET input and Terminal 12 is the ground reference.
Do not use Terminal 12 for power supply ground; Terminal 1 is power supply
ground.
The resistor value for phase current for a motor in the high performance configuration is
derived using the following equation:
I
-
7.2
)
I
(47,000)(
=
R
SET
SET
SET
Where R
SET
is the current set resistor and I
SET
is the desired current.
Table 5 (page 16) lists resistor values rounded off to the nearest 5% standard resistors
for both high performance (half winding) and low performance (full winding) operation.
Use the half winding values for operating 4 wire motors.
The maximum phase current of 7.2 amps is obtained with no CURRENT SET resistor
(Terminal 11 voltage equals 2.5 volts), Zero phase current occurs with CURRENT SET
shorted to ground (Terminal 11 voltage equals 0 VDC).
For best low speed smoothness, the motor phase current should not differ from the
manufacturer's rating by more than
±
20%. Currents substantially above or below this
may affect microstep accuracy and increase low speed vibration.
THE CN0162 DEFAULTS TO ITS MAXIMUM CURRENT OF 7.2 AMPS
PER PHASE IF NO CURRENT SET RESISTOR IS PRESENT. THIS
MAY CAUSE DAMAGE TO A MOTOR THAT IS TOO SMALL FOR THIS
CURRENT LEVEL.
