Mechanical Power Instrument Himmelstein Model 726

1550 Kingston Rd. #1116
Pickering, ON
L1V 6W9
TEL: 1 800 809 7167 CDA/USA
Load Cells/Transducers
Pressure Sensors
Torquemeter/Torque Sensor
Vibration/Shock Monitors
Mechanical Power Instrument Himmelstein Model 726

Model 726 Mechanical Power Instrument

These instruments are compatible with one current output (4-20 mA, 12±8 mA, 0±10 mA, or 0±20 mA) torque, force or pressure transmitter; and one frequency output sensor. They will also compute mechanical or fluid power and perform twenty (20) useful processing functions including limit checking, tare, hold and max/min capture. You needn't write code or add hardware to quickly be up and running a productive test.

The two line alphanumeric readout displays measured and computed data, units of measure and test status. Transducer calibration is automatic, requiring no manual adjustments.


  • Reads, Displays, Processes And Outputs
    • Shaft Torque, Speed, Power
    • Pump/Motor Head, Flow, Fluid Power
    • Drawbar Force, Velocity, Power
  • Built-in Ranges of 4-20mA, 12±8mA, 0±10mA, and 0±20mA
  • 2000 Samples/Sec. For DC Current Input Channels
  • 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
  • CE Marked


These instruments are compatible with virtually any transmitter or current source, and one frequency output sensor. They are particularly well suited for torque transmitters, pressure transmitters, or current sensors and frequency producing speed, flow, and velocity transducers..

They are compatible with Himmelstein 2 Wire Torque Transmitters: MCRT 3900X Series, Please consult factory for verification of compatibility.


Current Input

May be used either differentially/floating or single ended.


4-20mA, 12±8mA, 0±10mA, or 0±20mA selectable from the keypad or remotely

Overrange Capability

50% of full scale.

Input Protection

±130VDC or 130Vrms at each input to ground. Differential inputs protected by 62mA fuse.

Input Impedance

100 OhmΩ differential, 200k from negative input to ground.


Absolute calibration is automatic when current range is selected.

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.

Signal-to-Noise Ratio

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

Common Mode Rejection Ratio

>80dB DC to 10MHz.


0.01% of F.S.

Overall Accuracy (at 77oF/25oC)

0.02% of full scale typical, 0.03% of full scale, worst case.

Temperature Effects

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

Maximum Cable Length


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).

Low Pass Filter (keypad selectable)

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

Common Mode Rejection

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

Display Ranges and Resolution

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

Response Time

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

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

Type: 2 line by 16 alphanumeric characters, each 0.2" wide by 0.3" high. Backlit LCD with adjustable contrast.
Views: 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 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 driven testing. 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 function -- destination)

Type: TTL compatible, Schmitt Trigger, low-true with 47kΩ pull-up. Input current is -100A @ 0V.
Protection: to 130VDC (or 130Vrms).

Six Logic Outputs

(each with programmable function -- source)

Type: Open collector, low-true. Operating @ 24V (max) and 0.3A max sink current.
Protection: Short circuit (current and thermal limits) and overvoltage (0.5A fuse).

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

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

Serial Communication Port

(user selectable as RS232, RS422, or RS485)

BAUD Rate: 300 to 38400. Maximum Cable Length: 4000ft (RS422/RS485), 50ft (RS232).
Maximum Number of Devices: 32 (RS485), 1 (RS232/422).
120ohm 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 (100kohm) with respect to Earth Ground.
Commands: Control of all modes, settings, and measurements.

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: <1ohm/10kohm.
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 signal to noise spread. Measurements are made for a 1 minute interval using a 100 ohm source impedance.

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

3. Option MA converts voltage output to 4-20mA or 12±8mA current output(s). See Bulletin 389-1 for complete details.

4. Specification is subject to change without notice.

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