Downhole monitoring system (TMS) for ESPs

Post by **ALEngineer** » Mon Mar 30, 2026 1:06 am

The downhole monitoring system (TMS) measures key well and ESP parameters:

ESP motor and intake fluid temperature;
Intake pressure at the pump;
Vibration on the X, Y, and Z axes.

What's in the package:

SIU (surface interface unit, TMS): Installed inside the ESP control panel / VSD.
downhole sensor (TMS): Mounted on the ESP motor base.
Wellhead controller (KTM): Optional surface module for extra site I/O.

Why it matters:

Smart-well capability: Extra measurements support closed-loop and SCADA-driven decisions.
Stable link: Fast data channel between surface and downhole.
Digital control: Fully digital processing.
Independent power: The downhole sensor (TMS) is powered over the motor neutral, not a separate downhole supply.
Vendor-agnostic: Works with VSDs from many manufacturers.

20200128_115733.jpg

The SIU (surface interface unit, TMS) is the topside unit installed in the ESP control panel. It powers the downhole sensor (TMS), displays real-time data, and integrates with SCADA via Modbus RTU.

Technical summary: downhole monitoring system (TMS) specs

SIU (surface interface unit, TMS)
Typically installed inside the VSD (ESP control panel) or switchgear. Primary interface between the downhole sensor and the SCADA / control system.

Insulation monitoring: Tracks system insulation resistance (SUT / step-up transformer - lead cable - ESP motor) from 0 to 9999 kOhm.
I/O capability:

4 analog inputs (4-20 mA) for external sensors.
8 analog outputs (0-10 V) for data integration.
2 discrete inputs / 2 discrete outputs (up to 50 mA).
Comms: Supports RS-232 and RS-485 via Modbus RTU.
Power requirement: Standard 110/220 V AC supply.

Downhole sensor (TMS)
Mounted on the ESP motor base.

Data points: Intake pressure (up to 60 MPa), motor winding temp (up to 400°C), intake fluid temp, and 3-axis vibration (X/Y/Z).
Scan rate: 10-second update interval.
Power/comms: Data is transmitted via the motor neutral (wye / star point).
Dielectric strength: Rated up to 10 kV.

Wellhead controller (KTM-5) - optional
Additional surface module for expanded site monitoring.

Expanded I/O: 8 extra analog inputs (0-10 V and 4-20 mA) and 4 discrete inputs.
Interface: Connects via RS-485 (Modbus RTU).
Power: 16-42 V DC.