Agilent Technologies D, 66311B, 66309B, 66111A manual Open Sense Lead Protection

3 - Installation

Open Sense Lead Protection

The main output (output 1) of the dc source has built-in open sense protection circuitry that detects if there is an open in either the positive or the negative remote sense lead or load lead path. For battery powered devices, undetected open sense connections can cause incorrect battery charger calibration, incorrect test results due to erroneous voltage settings, and low voltage phone shutdown due to a large transient voltage drop.

To enable open sense lead detection from the front panel, press the Output key, use pto scroll to SENS:PROT, press …to select ON, then press Enter. To have the unit turn on with open sense detection enabled, save this state in location 0 and set the power-on state to RCL 0.

When this circuit is enabled, the sense and load leads are checked every time the output transitions from disabled to enabled (off to on). If a lead opens while the output is enabled, this will not be detected immediately by the open sense circuit. However, the output voltage will increase or decrease, depending on which one of the leads is open. Figure 3-5 illustrates the actual output voltage change that occurs with no load lead drop if a lead opens. Turning the output off, then on again, will cause the unit to check the output sense and load leads and determine if a sense lead is open.

19

18

17

16

15	Values will increase by about
	+0.3 V under load conditions

	14
	13																																				D
																																		CONNECTE
VOLTAGE	12
	11																																DS
																																	A
OUTPUT																															E	LE			N
	10
																														SE	NS		S OPE
																													BOTH
																																	+
	9
ACTUAL																											N
																									P	E
	8																							O
																							S
																					A	D
																				E
																			L
	7										N
																		E
										E							S
									P							N
							O								E
														S
	6					S							-
					-							D
										A	N
								+
	5						H
					O	T
				B
	4
	3
	2
				Values will decrease by about
	1			-0.1 V under load conditions
	0	2	3	4							5						6							7				8	9		10			11		12	13	14	15
	1

PROGRAMMED VOLTAGE

Figure 3-5. Output Voltage vs. Programmed Voltage with Open Sense Condition

36