Honeywell HMR4007 manual PIN Configuration, Circuit Description, Pin Number Pin Name Description

HMR4007

SENSOR PRODUCTS

PIN CONFIGURATION

Pin Number

Pin Name

Description

Digital Interface

1	RTS	Serial Clock Output
2	Data_Out	Serial Data Output
3	Data_In	Serial Data Input
4	CTS	Serial Clock Input
5	Power	Unregulated Power Input (+6 to +28 VDC) (see note 1)
6	GND	Power and Signal Ground
Analog Interface
1	Power	Unregulated Power Input (+6 to +28 VDC) (see note 2)
2	Analog Out	0 - 2.5 VDC analog output
3	Position Valid	TTL level (0 = position invalid, 1 = position valid)
4	GND	Power and Signal Ground
Jumper Block #1
2-5	Note 1	Analog Output port selected as power source
3-6	Note 1	Serial Communications port selected as power source

Note 1: The board contains three interface connectors for digital and/or analog communications. Power is supplied to the board through any one of these connectors and is selected by jumper block #1. All of the ground connections on all three ports are common to the circuit ground and are not affected by the jumper position. Only ONE of the three positions on JP1 should be shorted at a time. Shorting more than one may result in excessive power supply currents and board damage.

CIRCUIT DESCRIPTION

The HMR4007 Linear Position Sensor circuit board includes all of the basic sensors and electronics to provide a digital indication of position of a target magnet. The HMR4007 starts with an array of seven Honeywell HMC1501 single axis magnetoresistive (MR) sensors to determine the field geometry and direction of a target magnet attached to the moving part of a device under test. These sensors are supplied power by a constant voltage source, and the use of an array of sensors helps to maintain accuracy over temperature and run-out. The sensor outputs are routed to a multiplexed Analog to Digital Converter (ADC) integrated circuit. A microcontroller integrated circuit periodically queries the multiplexed ADC and performs sensor offset and gain corrections and computes the position of the target magnet as a function of the distance of travel along the long axis of the sensor board. The position data, along with an error bit, is available thought the serial interface or is present on the Digital to Analog Converter (DAC) output port. The serial interface is not needed in order to use the board’s stand-alone analog output. The microcontroller also performs the external serial data interface and other housekeeping functions. An onboard EEPROM integrated circuit is employed as a nonvolatile storage to retain necessary data and configuration variables for best performance.

The HMR4007 uses an on-board low drop out (LDO) +5 volt regulator so that a regulated +5 volt power supply or an unregulated power supply in the range of +6VDC to +28VDC can be used. The power is supplied to the board through one of the three user ports being (serial, analog, or USB) and a jumper is used to select which port is the power source. Only one jumper should be in place at any one time as the board does not have over current protection and use of more than one jumper can result in excessive power supply currents and board damage.

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