Heinrichs Messtechnik GmbH
Page 14 of 118
OPERATING MANUAL TMU-W / UMC4
Accuracy
Mass flow
Fluids
TMU-W004 and TMU-W006
± 0.1 % of actual flow ± zero point stability
(1)
TMU-W012
± 0.15 % of actual flow ± zero point stability
(1)
Repeatability error
± 0.05 % of actual flow (sensor with transmitter) ± ½ zero point stability
(1)
Mass flow
Gases
TMU-W004, TMU-W006 and
TMU-W012
± 0.5 % of actual flow ± zero point stability
(1)
Repeatability error
± 0.25 % of actual flow (sensor with transmitter) ± ½ zero point stability
(1)
Additional measured values
Volume flow
Not available
Temperature
± 0.5 °C
Hysteresis
n/a
Settling time
1 to 15 seconds
Startup drift
15 minutes
Long-term drift
± 0.02 % of upper-range value per year
Influence of ambient temperature ± 0.005 % per K
Influence of fluid temperature
Compensated
Influence of fluid pressure
For fluids: too small to be relevant
(1) Refer to section 3.3.2, “TMU-W flow ranges” for detailed information on flow ranges
Table 2: Flow-Rate Accuracy
Pressure loss in Hydrogen dispensers
The pressure loss of gases with constant mass flow is highly dependent on the operating pressure in the
mass meter and the resulting flow rate. The TMU-W is designed that its pressure lost will not exceed 30 bar
during a standardized refuelling operation with hydrogen and an empty vehicle tank, as defined in the
SAEJ2601. With an almost full vehicle tank, the pressure loss shall be much less than 20 bar.
Environmental Conditions
Ambient temperature
− 40 °C to + 60 °C (-40 °F to 140 °F)
Storage temperature
− 40 °C to + 80 °C (-40 °F to 176 °F)
Climatic category
In conformity with IEC 654-1. Unsheltered class D locations with direct open-air climate.
Ingress protection
Sensor: IP 67 (NEMA 6), Transmitter: IP68 / 1 m for 24 hours (NEMA 6P) acc. to DIN EN 60529 with
mounted and sufficiently tightened approved cable glands.
