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IL78A
IN-LINE AC Strain Gage Conditioner
1
G
ENERAL
The Model IL78A is a single-channel conditioner of phase-sensitive carrier-amplifier design.
Intended for applications involving transformer-coupling to the transducer bridge (as with rotary-
transformer torque sensors), this conditioner can also be used in conventional installations when
high sensitivity is required or where the electrical environment is especially noisy. Responding
only to the modulated carrier frequency, the IL78A rejects extraneous voltages that can cause
errors in DC systems, particularly when there is a need to "blow up" a portion of the transducer
range. User-adjustable phase and symmetry controls are provided.
The Model IL78A's is calibrated by means of a "two-point (dead-weight)" or shunt-calibration
technique, which are outlined in section three. The user can utilize the shunt calibration method
by adding the correct leaded shunt resistor value from "Cal Sense" to either + Sense or - Sense
depending on the polarity desired.
Top View of the Model IL78A AC Strain Gage Module (cover removed)
Shunt Operation:
selection. "EXT" is for an external - user installed shunt or "INT" for the internal - built in - 59K Ohm shunt. Installing the jumper
enables the selected feature. For an external shunt resistor, install the leaded resistor between the "Cal Sense" (pin 7) terminal
and either the + Signal (pin 5) or the - Signal (pin 6) terminals. Use the SW4 "Shunt" button to engage the shunt resistor across
the selected side of the bridge or "SHP or "SHN" logic input lines. For transducers with an installed shunt resistor, place the
jumper on the "EXT" teminals and wire the "Cal Sense" line to the transducer's shunt connector pin.
AC Strain Gage Phase Operation
Due to the AC modulated aspects of the IL78A AC Voltage excitation circuit, the IL78A8 contains a "PHASE"
adjustment which aligns the transducer's return output signal to the conditioner's demodulator. When the
demodulator is aligned properly through calibration, maximum amplitude and linearity are achieved.
92371.00 rev. B
D
ESCRIPTION AND
Located between the two screw terminal connectors, the IL70A contains a Shunt resistor jumper
GENERAL DESCRIPTION AND SPECIFICATIONS
M
ODEL
AC Strain Gage
C
ONDITIONER
S
PECIFICATIONS
IL78A
Module
IL78A.1
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Table of Contents
Summary of Contents for DayTronic IL78A
- Page 1 "EXT" teminals and wire the "Cal Sense" line to the transducer's shunt connector pin. AC Strain Gage Phase Operation Due to the AC modulated aspects of the IL78A AC Voltage excitation circuit, the IL78A8 contains a "PHASE" adjustment which aligns the transducer's return output signal to the conditioner's demodulator. When the demodulator is aligned properly through calibration, maximum amplitude and linearity are achieved.
- Page 2 WARNING Death, serious injury, or fire hazard could result from improper connection of this instrument. Read and understand this manual before connecting this instrument. Follow all installation and operating instructions while using this instrument. Connection of this instrument must be performed in compliance with the National Electrical Code (ANSI/NFPA 70-2014) of USA and any additional safety requirements applicable to your installation.
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Page 3: Safety Precautions
WARNUNG Der falsche Anschluß dieses Gerätes kann Tod, schwere Verletzungen oder Feuer verursachen. Bevor Sie dieses Instrument anschließen, müssen Sie die Anleitung lesen und verstanden haben. Bei der Verwendung dieses Instruments müssen alle Installation- und Betriebsanweisungen beachtet werden. Der Anschluß dieses Instruments muß in Übereinstimmung mit den nationalen Bestimmungen für Elektrizität (ANSI/NFPA 70- 2014) der Vereinigten Staaten, sowie allen weiteren, in Ihrem Fall anwendbaren Sicherheitsbestimmungen, vorgenommen werden. -
Page 4: Medidas De Seguridad
Medidas de seguridad Las medidas de seguridad siguientes deberán observarse cuando se realice cualquier tipo de conexión al instrumento. ο Cuando se haga conexiones a circuitos eléctricos o a equipo de activación por pulso, deberá abrirse sus respectivas cajas de seguridad. NO deberá hacerse ninguna conexión del instrumento en líneas eléctricas bajo tensión. ο... -
Page 5: Standard Accessories
Sicherheitsvorkehrungen Die folgenden Sicherheitsvorkehrungen sind immer dann zu befolgen, wenn eine Verbindung zum Instrument hergestellt wird. ο Öffnen Sie beim Anschluß an elektrische Stromkreise oder Impulsauslösungseinrichtungen die entsprechenden Unterbrecher. Es dürfen KEINE Anschlüsse an das Instrument unter stromführenden Spannungsleitungen montiert werden. -
Page 6: General Description And Specifications
IL78A AC Strain Gage Conditioner Module IL78A SPECIFICATIONS Measurement Range: Adjustable 0.5 mV/V to 5.0 mV/V; nominal full-scale Transducer Types: Conventional 4-arm strain gage bridges, typically transformer coupled - 120 to 10 k ohm Excita tion: 3.28 kHz; Nominal 2.77 Vac rms, sensed Power Supply : 11 - 28 Vdc regulated;... -
Page 7: Transducer Connections
AWG 16 to 30. NOTE: The recommended transducer cabling would be eight wire, individually shielded, twisted pair - wired as indicated (Fig. 1) Sense lines must be connected at the transducer (as recommended) or at the IL78A screw terminals - as a minimum. Table 2 denotes screw terminal assignments... - Page 8 When more than one IL78A is being used in the same measurment setup, beat frequencies can be produced by the excitation clock oscillator. To prevent this, the user should declare one of the IL78A units as a Master via switch 6 on the front panel. The other units should be switched to Slave and wired as shown with the SYC terminals connected and a separate Power Common wire.
- Page 9 IL78A AC Strain Gage Conditioner Module Fig. 4 Remote Shunt Activation Connections TRANSDUCER CONNECTIONS IL78A.2...
- Page 10 AC Strain Gage Conditioner Module 3 GENERAL DESCRIPTION AND CALIBRATION The Model IL78A is useful in applications involving tranformer coupling to the strain gage bridge (for example, rotary transformer torque sensors) and in certain appications that require high sensitivity with optimum signal-to- noise characteristics.
- Page 11 (see Figure 2). To perform calibration, proceed as follows. Turn power ON to the IL78A DC Power input terminal (11 to 28 Vdc input) The front-panel indicator should light green to indicate the application of dc power.
- Page 12 Note: Above calculation is useful in applications involving non - star bridge shunt calibration strain gage bridges (for example DC bridges, and slip ring type torque sensors). Rotary transformer type sensors which use star bridge shunt circuit will not equate properly and the sensor's published calibration data should be referenced. Calibration IL78A.3...
- Page 13 Master/Slave Connections. : When more than one IL78A is being used in a measurement setup (instruments are closely mounted or the transducer cabling is in a common conduit or raceway), beat frequencies may be produced from the 3-kHz oscillators used in the instruments to develop the excitation.
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Page 14: Verification Of Normal Operation
It is the purpose of this section to aid the user in determining, in the event of a malfunction to which the Model IL78A is suspected of contributing, whether the instrument is functioning normally or whether it is the source of the observed trouble. In the event the unit requires repair, the user may also contact the factory Service Department or the local Daytronic Representative for assistance. - Page 15 IL78A AC Strain Gage Conditioner Module Fig. 4 Star Bridge...
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Page 16: Product Warranty And Repair
AC Strain Gage Conditioner Module Product Warranty and Repair Daytronic Corporation warrants its products to be free from defects in material and workmanship, under normal and proper use in accordance with our instructions, for the period of time specified below. Our liability under such warranty or in...
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