HP 6623A, 6624A, 6621A manual RQS Bit, Reprogramming Delay, Display On/Off

Table 5-7 summarizes all the conditions under which a service request will be generated.

Table 5-7 Condition for Generating a Service Request

Condition	Commands Sent		State of
	PON	SRQ	RQS Bit
∙ Any	0	0	0
∙ Power-on	1	-	1
∙ Error	-	2 or 3	1
∙ Fault	-	1 or 3	1

Reprogramming Delay

The power supply may switch modes or become unregulated momentarily after a new output value is programmed. Because of their short duration, these cases may not ordinarily be considered a fault but the supply will recognize this deviation and generate a fault signal. To prevent this, the reprogramming delay feature is implemented.

Reprogramming delay will delay the onset of certain fault conditions and prevent the power supply from registering a fault when these conditions are true. When the delay is in effect, the CV, + CC, - CC and UNR bits of the status register are masked and cannot communicate with the mask and fault registers and the OCP function. This will prevent the supply from registering a fault should any of these bits become set during the delay period. Reprogramming delay is initiated when any of the following functions are executed:

VSET: ISET: RCL: OVRST: OCRST; OUT on/off

At power-on reprogramming delay is set to 20 mS. You can specify new values between 0 and 32 S in steps of 4 mS. If you specify a value which is not a multiple of 4 mS, the supply will round off the set value to the nearest 4 mS multiple.

To program a new value of 80 mS in output 2 for example, send the following:

DLY 2,.08

If you send a value outside the 0 to 32 S range you will get a programming error. You may use the programming response times in the specifications table to give you an idea of a typical delay setting. However, the appropriate delay setting will also depend on load capacitance, load resistance, and current limit setting. See page 51 for output capacitor considerations.

To query the reprogramming delay setting of a particular output channel, send the following query:

DLY? 2 (using output 2 as an example)

and address the supply to talk. The response will be a numeric value between 0 and 32.

Display On/Off

When the display is on, the commands sent across the HP-IB may experience a slower processing time because the processor must also spend time to monitor the outputs and update the display. You can shorten your command processing time by turning off the display. To turn off the display, send the command:

DSP 0

To re-enable the display send the command:

78 Remote Operation