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1. TEDS IEEE 1451.4 INTRODUCTION
The DPM-3 is a TEDS IEEE 1451.4 Plug and Play Smart Load Cell Meter. TEDS, or
Transducer Electronic Data Sheet, is a set of electronic data in a standardized format
defined within the IEEE 1451.4 standard. Stored in an EEPROM, this data specifies what
type of sensor is present, describes its interface, and gives technical information such as
sensitivity, bridge type, excitation, etc.
The DPM-3 automatically detects when a TEDS IEEE 1451.4 compliant Load Cell/Torque
Sensor has been connected to it by using a built-in EEPROM detector. Once such a sensor
has been detected, the DPM-3 displays a front panel TEDS indicator light, reads the
EEPROM, stores the information in memory, and performs an automatic configuration. The
built-in, sensor-related EEPROM may be of any of the following types: DS1973/DS2433,
DS2431 or DS1971/DS2430A. The automatic system configuration function performs all
steps needed to calibrate the TEDS IEEE 1451.4 compliant Load Cell/Torque Sensor and
DPM-3 as a system. This includes the configured precision of 32 bits, 19 bits or 11 bits and
the configured excitation voltage. Using the DPM-3 with a TEDS IEEE 1451.4 compliant
Load Cell/Torque Sensor is as easy as plugging a mouse into a computer, making it a true
plug and play experience.
The DPM-3 is safety certified to UL 61010-1 and to CSA C22.2#61010-1. It carries the ETL
certification mark for the USA and Canada.
2. GENERAL INTRODUCTION
DPM-3 digital panel meters are a versatile, cost-effective solution to a wide variety of
monitoring and control applications. They are easily set up to produce an accurate display
of weight, load or direct reading of microvolts. Setup can be via front panel pushbuttons or
the meter’s serial interface. Digital scaling of zero and span provides direct readout in engi-
neering units. Digital calibration of all ranges eliminates drift associated with potentiometers
found in non-microcomputer-based meters. Selective security lockout of the front panel keys
protects against accidental changes to the meter setup.
A unique method of analog-to-digital conversion provides 60 conversions per second (50 for
50 Hz operation), while integrating the signal over a full line cycle for maximum noise
rejection. Self-calibration cycles reduce the average reading rate to 56 per second (47 for
50 Hz). This fast read rate provides an accurate display of peak signal input and quick
response in control applications.
An adaptive auto-filter automatically selects a time constant appropriate for the encountered
signal noise level. This ensures stable displayed readings and outputs while responding
rapidly to changes of the input signal that exceed a selected threshold value. Input signal
polarity may be selected as normal or reverse.
The DPM-3 uses a lightweight, high-efficiency switching power supply that operates from
either AC or DC voltages and complies with safety regulations. The meter can be powered
worldwide without changes to the supply. An optional low voltage supply operates on 10 to
48 Vdc from batteries or 12 to 32 Vac from sources such as 400 Hz aircraft power. Both
supplies have an isolated 10 Vdc excitation supply to power transducers.
