Cooper Instruments & Systems DFI 1650 Multi-Channel Digital Force Indicator - Manual (Page 30)

CF 66 24 Rev. C 2/05
9.3.8 LIMIT.SOURCE Menu Item
This designates the data source of the channel monitored by this limit. Each channel has three data sources: the
live tracking value (TRACK), its highest value (PEAK), and its lowest value (VALLEY).
The options for this menu item are:
• “TRACK” means the live tracking value of the channel.
• “PEAK” means the highest value of the channel since the peak/valley detector was last cleared
• “VALLEY” means the lowest value of the channel since the peak/valley detector was last cleared
9.3.9 LEAVE MENU Menu Item
When the menu item is displayed, press [ENTER] to leave this menu. Press [EXIT] to return to the RUN mode.
10.0 STRAIN-GAGE INPUT CHANNEL
10.1 Features
The Strain-Gage Input channel provides a DC excitation voltage to and accepts millivolts signals from strain-gage
transducers. These millivolts signals are digitized, converted into engineering units, and placed into the track, peak
and valley data values of the channel. Setup and calibration of the channel can be made manually through the
SETUP mode or automatically if the transducers are equipped with Signature Calibration. See “What is Signature
Calibration? In Section 1.4”
The analog-to-digital converter input circuit is ratiometric to the excitation voltage, features adjustable digital, low-
pass filtering, 12- to 18-bit resolution (depending on the filter setting) and has several different mV/V input ranges.
These many input ranges allow ±50,000 count resolution (at the slowest filter setting) across a wide variety of mV/V
input ranges.
Three methods of calibrating the Strain-Gate Input channel to the transducer are available: known-load calibration,
shunt calibration and mV/V calibration. The benefits of each are discussed in “CALIBRATION TYPE Menu Item” in
Section 10.5.4
Two rear panel control inputs can be field-configured for such functions, as remote tare can be field-configured for
such functions as remote tare, disabling peak/valley detection and clearing the peak/valley values. A voltage or
current digital-to-analog output is also provided.
Many diagnostic functions are preformed automatically to insure correct wiring and operation of the transducer.
FP2000 Transducers
The Strain-Gage Input channel has its own internal shunt resistor for use in Shunt Calibration. It is not compatible
with FP2000 mV/V output transducers that are equipped with “Buffered Shunt Calibration”. If you wish to use Shunt
Calibration with an FP2000 transducer, use an FP2000 with Buffered Shunt cal and amplified output (e.g. 5 VDC,
10 VDC or 4-20mA) connected to a DFI’s High-Level Input channel.
10.2 Wiring
Connect the transducer to a Strain-Gage Input channel by wiring it to the 12-pin connector of that channel. The
System Calibration Sheet that shipped with the instrument describes which cards are installed in each channel.
The pin-out for this connector is shown on the following table.
Table 10-1: Strain-Gate Input Channel Pin Connections
Pin Label Function Reference Pin
1 (top) +EXC (+) Excitation 10
2 +SEN (+) Sense 10
3 -SEN (-) Sense 10
4 -EXC (-) Excitation 10
5 +SIG (+) Signal 10
6 -SIG (-) Signal 10