T-mass 65 Simulated Current Output Overview
T-mass 65 is a thermal mass flowmeter launched by Endress+Hauser, widely used for gas flow measurement. Its simulated current output function allows manual setting of 4-20 mA current values without actual flow, used for loop testing and system verification.

Function and Application Scenarios of Simulated Current Output
Main Functions
- Loop verification: Verify whether the current loop from the transmitter to the control system (DCS/PLC) is normal.
- System commissioning: Simulate flow signals to test host computer display and alarms when the pipeline is not filled with gas.
- Troubleshooting: Quickly determine whether the issue is with the instrument or the loop.
Application Scenarios
- New project commissioning phase
- Regular maintenance and calibration
- Loop verification after transmitter replacement
Simulated Current Output Setup Steps
Enter simulation mode via local display or debugging software (such as FieldCare), and follow these steps:
- Enter the main menu, select "Diagnostics" → "Simulation".
- Select the "Current Output" simulation option.
- Set the simulation value (e.g., 4 mA, 12 mA, 20 mA).
- After confirmation, the transmitter outputs the corresponding current and displays the simulation status.
- After testing is complete, exit simulation mode and resume normal measurement.

Comparison of Simulated Current Output Parameters and Normal Output
| Item | Simulated Current Output | Normal Measurement Output |
|---|---|---|
| Output Signal | Manually set 4-20 mA | 4-20 mA varying with flow |
| Applicable Conditions | No actual flow required | Actual flow required |
| Typical Uses | Loop testing, verification | Process control, metering |
| Exit Method | Manually exit simulation mode | Automatically follows flow |
Precautions and Troubleshooting
Precautions
- Simulation mode is for testing only, never enable it for long periods during normal production.
- The simulation value should be within the 4-20 mA range to avoid over-range alarms.
- After exiting simulation, confirm that the output matches the actual flow.
Common Troubleshooting
- No current output: Check loop power supply, wiring polarity, and fuses.
- Large current value deviation: Check whether the load resistance is within the allowable range (typically ≤ 500 Ω).
- Unable to enter simulation mode: Confirm user permission level; some parameters require an expert password.
Summary
T-mass 65 simulated current output is an efficient tool for commissioning and maintenance. Correct use can quickly verify the current loop and improve system reliability. Always follow the specifications during operation and exit simulation mode promptly after testing.