ElmoMC SimplIQ Analog Servo Amplifiers-Violin Operating Manual - Manual (Page 18)

Elmo Motion Control Rev 09/09 VIO-Velocity - Operating Manual
Page 14
3.3
Current Gain Control (CGC)
The amplifier is equipped with Current Gain Control (CGC) for improved performance of low induction
motors. By switching S3 to the ON position the gain of the current loop is reduced, thus enabling the use of
low inductance motors without the insertion of an additional inductor. The default (S3 OFF) is high gain.
Switching S3 to the ON position reduces the proportional gain (P) of the current loop by approx. 70%. In
the following table, minimum inductance values can be calculated.
Minimum inductance for High Gain Minimum inductance for Low Gain
25/50 L
Load (millihenry)
> 2.4*10 -3 * V
supply (Volt)
L
Load (millihenry)
> 0.9*10 -3 * V
supply (Volt)
15/55 L
Load (millihenry)
> 4*10
-3
* V
supply (Volt)
L
Load (millihenry)
> 1.6*10
-3
* V
supply (Volt)
10/100 L
Load (millihenry)
> 9*10 -3 * V
supply (Volt)
L
Load (millihenry)
> 2.2*10 -3 * V
supply (Volt)
15/100 L
Load (millihenry)
> 6*10
-3
* V
supply (Volt)
L
Load (millihenry)
> 1.5*10
-3
* V
supply (Volt)
6/200 L
Load (millihenry)
> 16.5*10 -3 *V
supply (Volt)
L
Load (millihenry)
> 4*10 -3 * V
supply (Volt)
15/200 L
Load (millihenry)
> 6.6*10
-3
*V
supply (Volt)
L
Load (millihenry)
> 1.6*10
-3
* V
supply (Volt)
Table 8: Minimum inductance values
3.4
External Current Limit - Continuous (ECLC)
The amplifiers' continuous current limit can be reduced by an external voltage or by a fixed resistor R9. .
For most applications using a fixed resistor will be the preferred method.
3.4.1 ECLC external voltage
An external positive voltage (0 to 3.75V) to terminal ECLC in reference to terminal ECLRET will control
continuous current limit from zero to Ic (nom).
) ( *
75 . 3
) ( nom I
V
V
new I
C
ECLC
C
=
Remarks:
The voltage will be internally clamped to 3.75V whenever the external V
ECLC
will be higher
than 3.75V.
The external voltage source must be capable to source/ sink at least ±0.2 ma.
The max absolute V
ECLC
is 12V.
3.4.2 Continuous current limit resistor
The user can change the continuous current limit by calculating and inserting R9. The value is given by:
1
) (
) (
* 4 . 37 ) ( 9 − =
nom Ic
new Ic
Kohm R
Remarks:
• 0 < R9 < 36.4K (1/8 Watt)
• If R9 is larger than 36.4K the current limit will be internally clamped to the nominal value.
• I
C (nom)
is the nominal continuous current limit of the amplifier.
3.5
External Current Limit - Peak (ECLP)
The amplifiers' peak current limit can be reduced by an external voltage or by a fixed resistor R10. . For
most applications using a fixed resistor will be the preferred method.