Raven Installation Guide
Chapter 4: Servo Control Operation
4.1Current 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.
4.2CFM
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.
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| Current | Differential |
| Continuous | Peak Current | Current | Monitor | Input |
| Current limit | Limit | Gain(A/V) | (V/A) | 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 default (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
