Mechanical Power Instrument Himmelstein Model 723

1550 Kingston Rd. #1116
Pickering, ON
L1V 6W9
TEL: 1 800 809 7167 CDA/USA
Load Cells/Transducers
Magnetic Sensors
Pressure Sensors
Torquemeter/Torque Sensor
Ultrasonic Sensors
Vibration/Shock Monitors
Mechanical Power Instrument Himmelstein Model 723  

Model 723 Mechanical Power Instrument

These advanced instruments provide engineering unit display of a high level (±1V to ±10V) dc input and a frequency input. They also compute power and perform 21 functions including limit checks, tare, hold, and max/min capture. You needn't write code or add hardware to be up-and-running a productive test.

The two line alphanumeric readout displays measured and computed data, units of measure and test status. To calibrate, enter full scale in engineering units, instrument will provide 0.01% resolution and ±5V and/or ±10V analog outputs at full scale.


  • Reads, Displays, Processes And Outputs
    • Shaft Torque, Speed, Power
    • Pump/Motor Head, Flow, Fluid Power
    • Drawbar Force, Velocity, Power
  • Fast, Rock Solid Readings With High Noise Immunity
  • 2000 Samples/Sec. For Torque, Head Or Drawbar Force Input
  • 1 Millisecond Response For Speed, Flow Or Velocity Input
  • 6 Digit Engineering Unit Display With Legends And 0.01% Resolution
  • RS232, RS422 Or RS485 Serial Communication
  • Auto-Scaled ?±5v And/Or ?±10v Analog Outputs
  • No Pots, Batteries, Fans, Maintenance, Or External Power Supplies


These instruments are compatible with one dc output sensor, and one frequency output sensor. They are particularly well suited for dc output torque, force, and pressure sensors, and frequency producing speed, flow and velocity transducers.

They are compatible with Himmelstein Torquemeter Models: MCRT 4800VT Series, MCRT 48000V Series MCRT 4900V Series, MCRT 49000V Series MCRT 27000V Series Wheel Torquemeters. Please consult factory for verification.


Voltage Input

May be used either differentially or single ended.


1V to 10V. Maximum allowable (no damage) input is 130VDC or 130Vrms.

Overrange Capability

50% of full scale.

Zero Control Range

10% of full scale (F.S.) with 50% overrange and 60% of full scale with 0% overrange.

Input Impedance

2MΩ differential, 1MΩ single ended.


Dual polarity calibration with engineering unit scaling.

Antialias Filter

5 pole Bessel response filter.

Low Pass Filtering

4 pole Bessel response digital filter with 11 cutoff frequencies from 0.1 to 200Hz in 1-2-5 steps.

Common Mode Rejection Ratio

>80dB DC to 10MHz.

Signal-to-Noise Ratio1

with 1/10/100/200Hz filters 86/80/72/66dB.


0.01% of F.S.

Overall Accuracy (at 77oF/25oC)

0.01% of full scale typical, 0.02% of full scale, worst case.

Temperature Effects

Zero: 0.001% of F.S./F (max); Span: 0.001% of F.S./F (max).

Excitation Supplies2

+15V@100mA and +5V@250mA short circuit (current limit) and overvoltage (fuses) protected.

Frequency Input

Any uni-directional or bi-directional (quadrature) source including self generating and zero velocity speed pickups, optical encoders, flowmeters, etc. When used with bi-directional sensors, the conditioner outputs both direction and magnitude

Input Impedance and Configuration

Differential or single ended inputs. 100kΩ differential, 50kΩ single ended.

Input Threshold (keypad selectable)

10, 20, 50, 100, or 200mVpk-pk (between inputs) or TTL.

Maximum Voltage

130VDC or 130Vrms.

Input Signal Bandwidth

0.001 to 200kHz (10 to 200mV pk-pk threshold), 0.001 to 400kHz (TTL threshold).

Display Ranges and Resolution

Rangeless (use any F.S. Engineering Unit value) with 50% overrange. Resolution is 0.01% of F.S.

Low Pass Filter (keypad selectable)

20kHz (-3dB) or none. This filter is not available for TTL inputs.

Response Time

Greater of: 1 ms, typical (2 ms worst case) or the input pulse length.

Common Mode Rejection

80dB (60Hz), 55dB (0 to 10kHz).

Low Pass Filtering of Sampled Data

Unfiltered or 4 pole Bessel filter. Cutoff frequencies from 0.1 to 100 Hz in 1-2-5 steps.

Overall Accuracy

0.01% of F.S. @ +77oF (+25oC), 0.015% of F.S. @ +41oF to +122oF (+5oC to +50oC).

Excitation Supplies3

+12V@125mA or +5V@250mA. short circuit (current limit) and overvoltage (fuses) protected.

Maximum Transducer Cable Length

1000 ft.

System Display

2 line by 16 alphanumeric characters, each 0.2" wide by 0.3" high. Backlit LCD with adjustable contrast.


Select either 2 Channels, 1 Channel with Limit Status, or 1 Channel with I/O Status.

Data Displayed

Select from Current, Max, Min, Spread, Held data and Tare value.

Data Format

Engineering units with 6 digits (1-2-5 format) and 5 character, upper or lower case, user-entered legend/descriptor.

System Response
(per channel)

Data Sampling & Max/Min Update Rates: 2000Hz (hardware channels), 50Hz (CH3 calculation).

Limit Checking Rate: 1000Hz (hardware channels), 50Hz (CH3 calculation).

Logic I/O Response Time: 1ms (hardware channels), 20ms (CH3 calculation).

Update Rate for Each Analog Output: 1000Hz.

System Control

All I/O functions can be ORd in any combination. The pattern function adds ANDing capabilities.

Input Actions/Channel

Logic inputs, outputs, and internal Matrix signals control following actions. Tare, Clear Tare, Hold, Clear Hold, Reset Max/Min, Clear Latched Limits, Check Limits, Do Max/Mins, Apply +CAL, Apply -CAL.

Output Events/Channel

The following events drive Logic outputs and internal Matrix signals. HI Limit, NOT HI Limit, IN Limit, NOT IN Limit, LO Limit, NOT LO Limit, At Max, NOT At Max, At Min, NOT At Min.

Eight User-defined Patterns

Patterns of Logic inputs, outputs and Matrix signals drive Logic outputs and internal Matrix signals.

State Machine Capability
User enabled/disabled. Permits up to eight states and allows event driventesting. See AN7000 for details.

Limit Checking

Each channel has a HI and LO limit which may be latched or unlatched, absolute or signed, and with or without hysteresis. Select either Current, Max, Min, Spread or Held data for limit checking. Limit violations on any or all channels can be set to trigger backlight flashing in any of the display view modes.

Four Logic Inputs

Each with programmable destination, protected to 130VDC or 130Vrms.


TTL compatible, Schmitt Trigger, low-true with 47kΩ pull-up. Input current is -100μA @ 0V.

Six Logic Outputs

Each with programmable source, short circuit (current and thermal limits) and overvoltage (fuse) protected.


Open collector, low-true. Operating @ 24V (max) and 0.3A max sink current.

External +5VDC Power (on I/O connector)

250mA, short circuit (current limit) and overvoltage (fuse) protected.

Serial Communication Port

(selectable as RS232, RS422, or RS485. Supports 32 devices on RS485 port and 1 device on RS232/422)


300 to 38400. Maximum Cable Length: 4000ft (RS422/RS485), 50ft (RS232).

120Ω Termination Resistors (RS485)

user selectable for RXD and TXD.

RS422/485 Transceivers

Slew-rate limited, short circuit protected (current & thermal limits).

RS232 Drivers

Short circuit protected (current limit).

Serial I/Os

Use a 9 pin D connector. They are 15kV ESD protected and float (100kΩ) with respect to Earth Ground.

Non-Volatile Memory Storage for System Settings

EEPROM, batteries are not used.

Dual Analog Outputs

(each assignable to any of the displayed channels)

Output Impedance/Minimum Load Resistance: <1Ω/10kΩ.
Full Scale: 5V or 10V (user selectable). Resolution is 2mV @ 5V FS or 4mV @ 10V FS.
Overrange: 8.2V @ 5V FS or 13.5V @ 10V FS.
Non-linearity: 2mV @ 5V FS or 4mV @ 10V FS.
Overall Error (worst case, including temperature effects): 5mV @ 5V FS or 10mV @ 10V FS.
Filter: 100Hz, 5 pole Bessel response low pass filter.
Protection: Short circuit (current limit) and overvoltage (0.25A fuse) protected.

Size and Weight

6.5" wide, 2.9" high, 8.7" deep. Weight is 3 pounds.

Operating Temperature

+41oF to +122oF (+5oC to +50oC).

Input Power

90VAC to 250VAC, 50/60Hz @ 25VA, max. Two 2A/250V fuses, line filter, and rear power switch.


1. The ratio expressed in decibels (dB), of full scale (F.S.) signal to noise spread. Measurements are made for a 1 minute interval using a 100 Ω source impedance.

2. Both excitation voltages can be used simultaneously with the following restrictions: 6 (15V current) + (5V current) ≤ 700mA AND 15V current ≤ 100mA AND 5V current ≤ 250mA.

3. Both excitation voltages can be used simultaneously with the following restrictions: 4.8 x (12V current) + (5V current) ≤700mA AND 12V current ≤ 125mA AND 5V current ≤ 250mA

4. Specification is subject to change without notice.

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