Firma:              Perkin Elmer

Modell:            Nelson Ser.900

Kommentar:   Dokumente engl.

The PE Nelson 950A and 970A (collectively, the 900 Series) Intelligent Interfaces are analog-to-digital interfaces that acquire data and store it in a local buffer memory. The readings are transmitted to the host computer through either an IEEE-488 General Purpose Instrumentation Bus or an RS-232C serial link. Each Intelligent Interface is capable of multiplexing data from two detectors during a single run. Four programmable voltage ranges are available: 10 V, 2 V, 1 V, and 0.1 V. Each voltage range provides a dynamic range of

1:1 000 000 at a sampling rate of 10 Hz.

The Intelligent Interface has two sense input lines (START and STOP). It contains 7 relays that can be programmed by a host computer to control external devices and one system READY relay for communicating with an autosampler. The Rack and Vial Port allows the Intelligent Interface to read digital data at TTL signal levels from autosamplers. The Front Panel provides membrane switches for local control of the interface by the user and an LED display for power, READY, and data range status.

Internal to the Intelligent Interface is a HD64180 microprocessor that executes commands received from the host computer. These commands are part of the chromatography software provided in the PE Nelson Turbochrom, 2600, 4400, or PC Integrator data systems. There are two versions of the interface: the 950A and the 970A. The versions are distinguished only by the available memory, which is 16K and 256K bytes respectively. Memory usage in the interface is kept to a minimum by a delta modulation scheme that stores only the difference between successive readings. On average, each data point can be represented by about 2 bytes of internal storage. The actual amount is a function of the sampling rate and the voltage swing in the data. The segmented memory feature allows individual runs to be separately stored in a First-In-First-Out (FIFO) buffer that optimizes memory allocation.

Interface Models and Memory Options

The 900A Series Interface can be configured for unipolar or bipolar operation at any one of four input voltage ranges. The Input voltage range is specified in the acquisition method of the host software. The polarity mode is specified using the Setup switches on the Back Panel. The available input voltage ranges are tabulated in the "Technical Data" section.

TECHNICAL DATA

Dynamic Range:           1 000 000 Counts/Period.

                                      Sampling Period = 0.1 s

                                      (10 000 000 x Sampling Interval in s)

                                      Counts/Period.

                                      Sampling Period 0.1 s

                                      1 Count = 1 µV On 1 V Scale)

Input Impedance:         10 Mohms Differential Input

Input Ranges:

                                                                  Operating Range, V

                                      Nominal

                                      Range, V         Unipolar                             Bipolar

                                      0.1                    -0.0005 to +0.0995             -0.05 to +0.05

                                      1.0                    -0.005 to +0.995                 -0.5 to +0.5

                                      2.0                    -0.01 to +1.99                     -1.0 to + 1.0

                                      10.0                  -0.05 to 9.95                       -5.0 to + 5.0

Resolution:                   0.1 µV on 0.01 Volt Scale at 10 Hz

                                      1.0 µV on 1.0 Volt Scale at 10 Hz

                                      2.0 µV on 2.0 Volt Scale at 10 Hz

                                      10.0 µV on 10 Volt Scale at 10 Hz

Sampling Rate:            100 Hz to 0.1 Hz

Maximum Gain Error: ± 2.5 %

Maximum Std. Dev.

Gain Error:                   ± 0.17

Maximum Nonlinearity:        ± 0.10% FS

Rack/Vial &                   Contact Closure or TTL Compatible

Start/Stop Inputs:        0.0 V to 0.8 V = "LOW"

                                      2.8 V to 5.0 V = "HIGH"

                                      Hold "LOW" at least 10 ms

                                      Level Sensitive/Not Latched

Relays:                          24 VDC.

(Max Rating)                 0.5 Amp or 12 VA (When Relay Is CLOSED)

                                      10 ms Cycle Time

Power/                           100/ 120/220 VAC +10%, -13%

Operating:                    240 VAC +15%, -10%

                                      120 VA MAX at 47 - 63 Hz

Consumption:              <16 Watts

Fuse:                             0.750 Amps for 100-120 VAC

                                      3AG, Normal Blow (U.S. and Canada)

                                      0.400 Amps for 220-240 VAC

                                      Type T DIN, (Europe and Other)

ESD Protection:           15 KV Discharged through 150 pF and 150 Ohms

Temperature:               0 to 45 degrees C