Novatel OEM7 SPAN, Инструкция по установке и эксплуатации

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Chapter 3 SPAN Operation
OEM7 SPAN Installation and Operation User Manual v14 108
NovAtel products that support quadrature encoding also accept a single channel DMI input. In the case of a
single channel, only the A+/A- differential wire pair is connected. A single channel provides benefit to the SPAN
solution by measuring only the distance traveled without regard for direction.
3.7.2 DMI Connection
Depending on the SPAN system components, the DMI can be connected to a PwrPak7, an IMU, a UIC or an
intermediate processor.
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PwrPak7
For a SPAN system with a PwrPak7, the DMI can be connected to the HD26 COM PORTS connector on the
PwrPak7.
For information about connecting and configuring a DMI connected to a PwrPak7, see
DMI Connected to a
PwrPak7 on page 110.
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IMU Enclosure
For a SPAN system with an IMU-HG1900, IMU-ISA-100C, IMU-ENC-LN200 or IMU-µIMU-IC, the DMI can
be connected to the Wheel Sensor port on the IMU enclosure.
For a SPAN system with an IMU-IGM-A1 or IMU-IGM-S1, the DMI is connected to the AUX port on the
enclosure.
For a SPAN system with an IMU-FSAS or IMU-CPT, the DMI can be connected to the IMU connector.
For information about connecting and configuring a DMI connected to an IMU, see
DMI Connected to an IMU
on page 112.
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UIC
For a SPAN system that uses a UIC to connect the IMU to the receiver, the DMI can be connected to the
UIC.
For information about connecting and configuring a DMI connected to a UIC, see
DMI Connected to a UIC on
page 114.
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Intermediate processor
NovAtel’s OEM7 receiver cards do not handle DMI encoded signals natively. If using a receiver card, an inter-
mediate processor is required to convert DMI pulses into NovAtel commands (RAWDMI).
For information about connecting and configuring a DMI connected using an intermediate processor, see
DMI
Connected to an Intermediate Processor on page 116.
3.7.3 DMI Requirements
The PwrPak7, UIC and certain IMU enclosures are compatible with any wheel sensor meeting the following
requirements:
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Output signal duty cycle is symmetric 40% to 60%.
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Output signal voltage is RS-422 compliant (differential).
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The wheel sensor is powered externally. The receiver does not supply power to the wheel sensor.
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Quadrature, pulse and direction wheel sensors are compatible.
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Expected maximum pulse rate over measurement range does not exceed the product-dependent limit
described in
Table 26: Wheel Sensor Maximum Pulse Rates on the next page.