DM-TT200 Head-Mount Temperature Transmitter, 4-20 mA / HART

Overview

The DM-TT200 converts an RTD or thermocouple signal into a 4-20 mA loop inside the connection head, metres away from the measurement point. That short analogue path is the whole point: the low-level sensor signal stays inside a shielded head instead of travelling down a cable next to a drive, and the control system receives a robust current loop.

The input is universal and configured by software, covering PT100, PT1000, Ni1000, thermocouple types K, J, T, E, N, R, S, B, and millivolt or resistance inputs. Sensor matching (Callendar-Van Dusen coefficients) can be entered for a specific probe, which brings a standard Class A element closer to a calibrated pair without buying a tighter element.

Key features

• Universal input: RTD, thermocouple, mV, resistance
• 4-20 mA output with HART 7 digital communication
• 1,500 VAC galvanic isolation between input and output
• Sensor matching via CVD coefficients for individual probes
• Sensor break and short-circuit detection with configurable drive
• Fits DIN B connection heads, 34 mm diameter, 22 mm height

Typical applications

• Process temperature loops on RTD and thermocouple probes
• Retrofit of direct-wired RTDs onto an existing 4-20 mA card
• Hazardous-area loops with intrinsic safety barriers
• Sanitary probe assemblies in food and pharmaceutical service

Commissioning note

Configure the input type and range before installation, then verify the loop current at two points. A transmitter configured for a 3-wire PT100 on a 4-wire probe will read a plausible but wrong value, which is harder to find later than an outright failure.