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Model 2701 Fast Data Rates Using Front Panel Controls

Introduction
The Model 2701 maximum data rate is specified at 3500 readings per second1. To
achieve this rate there are several parameters that must be configured. Not all of the parameters
are available through front panel controls. This technical note describes a technique to configure
the 2701 for maximum speed with a remote connection and how to save this set up in order to
achieve the maximum data rate using the front panel controls at a later time without the remote
connection.

Setting Parameters
Four parameters can be controlled from the front panel to configure the Model 2701 for high
speed. With this configuration the data rate achieved is about 220 readings per second. These
parameters and their settings are as follows:

1. Rate = Fast
2. Range = fixed
3. Filter = Off
4. Delay = Off

But this is not the maximum rate the data can be obtained with the Model 2701.
The following additional parameters need to be configured in order to obtain the maximum data
rate.

1. Rate = 0.002 NPLC (Fast from front panel is 0.1 NPLC)
2. AutoZero = Off
3. Trigger Count set to 1
4. Sample Count set to 1000 or higher

These parameters are only controlled through software control over a remote connection
(Ethernet or RS-232). Once these parameters are set, the entire configuration could be saved in
memory. Then this configuration is recalled from memory using front panel controls. The fast
3500 readings/sec rate is now achievable from front panel controls.

The memory is nonvolatile so the parameters remain intact when power is off. Once the
configuration is set it will not change unless overwritten with new settings. Up to four different
configurations can be saved in memory.

The following is a sample of SCPI command codes to configure the Model 2701 for maximum
data rate.

*RST Reset Model 2701
:SENSE:VOLT:DC:NPLC 0.002 Set 0.002 Line Cycle Integration
:SENSE:VOLT:DC:RANGE 10 Fix range to 10V
:SENSE:VOLT:DC:AVERAGE:STATE OFF Disable Filter
:TRIGGER:DELAY 0 Trigger delay set to 0.0
:SYSTEM:AZERO:STATE OFF Disable AutoZero function
:TRIGGER:COUNT 1 Trigger count = 1
:SAMPLE:COUNT 1000 Take 1000 readings for every one
trigger
*SAV 1 Save configuration in memory 1




1
This is the speed of the 2701 mainframe without any switching.
These commands set the Model 2701 configuration for maximum speed. This is only achieved
when the memory location is invoked. Once the configuration is downloaded it must be recalled
on the front panel in order to obtain the high reading rates.
For example...
1. Press SHIFT.
2. Press SETUP.
3. Use the left arrow and up/down arrows to select the Saved configuration (e.g. SAV1).
4. Press ENTER.
5. Now the configuration is restored.

Maximum speed may not be the exact rate required for some applications. The most important
parameter to affect speed is the rate command (NPLC). Table 1 contains some typical reading
rates for various NPLC configurations. This is with storing 1000 readings into the buffer and
monitoring the elapsed time with the time stamp feature.

NPLC Readings per Second Resolution
.002 3500 3