Agilent Technologies Setting 82357A High-Performance Operation, Setting T1 Value With Sicl

Using the 82357A

Setting Configuration Parameters

Setting 82357A High-Performance Operation

Introduction

Setting T1 Value With VISA

NOTE

Changing the T1 delay as described in this section is an advanced feature and also requires attention to cable lengths and other system features.

The GPIB transfer rate for 82357A writes using large (>1000 bytes) buffer size is affected by the Data Available (T1) delay time. (The transfer rates are not noticeably affected when the buffer size is <1000 bytes). The default delay time used by the 82357A is 800 nsec.

The maximum transfer rate for T1 = 350 nsec is about 900 KBytes/sec as compared to about 650 KBytes/sec for the 82357A default value of 800 nsec. Changing the T1 delay affects ONLY the write performance of the 82357A.

To set the T1 value with VISA, use the VI_AGATTR_GPIB_T1_DELAY attribute. The VI_AGATTR_GPIB_T1_DELAY value is the time of the T1 delay in nanoseconds, and should be no less than VI_AG_GPIB_T1DELAY_MIN

or no greater than VI_AG_GPIB_T1DELAY_MAX. This value is defined in Agilent's 'visa.h' header file. To use this value, you must '#define AGVISA_ATTRIBUTES' before the '#include "visa.h" in your C or C++ source file.

The 82357A supports T1 delays from 350 nsec to <max_value> in steps of 40 nsec. You can find out the actual value by calling viGetAttribute().

Attribute	Access Priv.	Data Type	Range (nsec)	Used By
VI_AGATTR_GPIB_	RW Global	ViInt32	VI_AG_GPIB_T1DELAY_MIN to	GPIB INTFC
T1_DELAY			VI_AG_GPIB_T1DELAY_MAX	resources

Setting T1 Value With SICL

To set the T1 value with SICL, use the igpibsett1delay() command and modify the GPIB environment. For further information, you may want

to see the Hewlett-Packard document “Tutorial Description of the Hewlett- Packard Interface Bus”. See Section 2.12, Optimizing Performance.

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