Elmo ISP manual Current loop, Current limits, Time dependent peak current limit

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4.4Current loop

Current loop control is obtained by op amp U1/B (Current amplifier) and R7, C2 which form a lag-lead network for current loop. The standard amp is equipped with R7 (100Kohm) and C2 (0.01 æF) to get optimum current response for an average motor in this power range. These components are mounted in solderless terminals.

4.5Current limits

The servo amplifier can operate in the following voltage-current plane:

				+V
-Ip		-Ic			Ic	Ip
Intermittent		Continuous
zone		zone		-V
	Ic - Continuous current				Ip - Peak current
			Fig. 4.1: Voltage-Current plane

Each amplifier is factory calibrated to have this shape of voltage-current operating area with rated values of continuous and peak current limits. In addition the peak current limit is time dependent as explained in 4.5.1.

4.5.1Time dependent peak current limit

The peak current is so designed that its duration is a function of the peak amplitude and the motor actual operating current before the peak demand. The maximum peak current is available for 1.6 second. The duration of Ip is given by:

ISP - Rev 6/95