KEPCO EL Series Electronic Load Operator Manual P/N 243-1295 Firmware Version 1.232 (Unit Rev 0 or 1) - Manual (Page 53)

SERIES EL 063010
3-19
Status registers
• 4 - MAV — Message Available, set if an error message is available in the Message
Queue.
• 5 -ESB — Event Status Summary, set if an enabled standard event occurs.
• 6 - MSS — Master Status Summary.
• 7 - OPER — Operation Status Summary, set if an Operation event occurs.
3.11 DAMPING
Typical operation for an electronic load involves the flow of high currents. Often these currents
flow through long interconnections. The combination of high, rapidly changing currents and the
inductance associated with connections to the load can cause unexpected results, such as very
high voltage spikes, oscillation or severe ringing (damped oscillations) at the source.
To help reduce these issues, the Series EL offers multiple forms and degrees of damping to
allow the best measurements possible.
There are two forms of damping in the Series EL load: 1) System Damping, which dampens the
response of the main control loop and 2) Mode Damping that dampens effects at the Power FET
Modules by modifying the individual FET loop characteristics. Increased system damping
reduces the tendency for oscillation and reduces response time to high speed transients.
Increased Mode damping decreases the loop's response time to transients. These two damping
functions have a great deal of interplay. For best results, follow the guidelines of PAR. 3.11.1.
3.11.1 DAMPING ADJUSTMENTS
The factory default settings for damping sets the overall system damping at maximum and the
Power FET Module damping at mid-level. It should be noted that once changed, these damping
settings are stored in non-volatile memory; the new values are retained until changed again. For
most applications the factory settings should provide optimum damping, however, if you have a
special situation, damping adjustments are best made using a test set up as shown in Figure 3-
6.