Raven Installation Guide
MAN-RAVIG (Ver. 1.1)
4-1
Chapter 4: Servo Control Operation 4.1 Current Command Input
The Raven has two differential inputs. The input operating voltage range is ± 3.75 V,
meaning that a 3.75 V signal will result in a fully rated peak current. The current limit
circuits will override this signal if the peak duration exceeds 2.7 seconds and/or the
required current exceeds the values set by the ECLC and ECLP signals. If the input
command voltage exceeds 3.75 V, input scaling must be implemented by adding a pair of
external resistors, according to the following formula:
Rin (KΩ) = (5.33 * Vin) - 20
Be careful not to apply input voltage above the maximum allowed input voltage as this
will cause the input operational amplifier to operate beyond its limits (+20 V) and in
extreme cases, may even damage it.
4.2 CFM
The amplifier is equipped with a current feedback multiplier (CFM). Connecting pin J2/6
to J2/5 multiplies the signal of the current feedback by 2 and consequently causes the
following changes to occur:
Current gains are divided by 2.
Current monitor is multiplied by 2.
Current limits are divided by 2.
This function should be activated whenever the rated current and the peak current of the
motor are less than 50% of the amplifier rated continuous and peak limits, respectively.
Continuous
Current limit
Peak Current
Limit
Current
Gain(A/V)
Current
Monitor
(V/A)
Differential
Input
Impedance
Without CFM Ic Ip Ip/3.75 3.9/Ip 40 kΩ
With CFM Ic/2 Ip/2 Ip/7.5 7.8/Ip 40 kΩ
Table 4-1: CFM Effects
The defaul t (pin J2/6 left open) is the low current feedback.
For permanent selection, a simple short is recommended.
For remote selection, the scheme in Figure 4-1 should be used.