Minco TT115, TT155, TT297, TT165 Operating Instructions

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TT115/TT155/TT165/TT297 TemptranTM

2-wire Temperature Transmitter for RTD Thermometers

Installation and Operating Instructions

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Description

Designed for use in room air applications, model TT115/TT155/TT165 is a 2-wire temperature
transmitter for RTD (Resistance Temperature Detector) thermometers. The TemptranTM
converts the RTD's signal into a 4 to 20 mA DC current. The current changes according to the
range in which the Temptran is calibrated: 4 mA at the lowest temperature of the range, rising
to 20 mA at the top of the range. The leads that supply power also carry the current signal.

Note: Transmitter circuit board only, Room Air housing and RTD sold separately.

Specifications

Sensing Element:

100 ohm platinum RTD, 0.00392 ohm/ohm/°C TCR,

100 ohm platinum RTD, 0.00391 ohm/ohm/°C TCR,
100 ohm platinum RTD, 0.00385 ohm/ohm/°C TCR,

1000 ohm platinum RTD, 0.00385 ohm/ohm/°C TCR
1000 ohm platinum RTD, 0.00375 ohm/ohm/°C TCR

Output:

4 to 20 mA DC over specified range, limited to 30mA maximum.

Calibration Accuracy:

± 0.1% of Span

Transmitter Linearity:

± 0.1% of Span.

Physical:

Printed circuit board designed to mount inside the S470 series
thermostat housing with RTD

Operating Environment:

32° to 122°F (0° to 50°C), non-condensing.

Storage Environment:

-67° to 212°F (-55° to 100°C), non-condensing.

Ambient Temperature

Effects:

± 0.007% Span/°F (± 0.014% Span/°F for Spans < 100°F)

Warm-up Drift:

± 0.1% of Span max., assuming Vsupply = 24 VDC and Rloop =
250 ohms. Stable within 30 minutes.

Supply Voltage:

8.5 to 35 volts DC, non-polarized.

Input Voltage Effect:

± 0.001% of span per volt from 8.5 to 35 VDC.

Maximum Load

Resistance:

The maximum allowable resistance of the signal-carrying loop,
including extension wires and load resistance, is given by this
formula: Rloop max = (Vsupply-8.5)/.02 amps. For example, if
the supply voltage is 24 VDC, the loop resistance must be less
than
775 .

System Integration:

Output “High” (22-28mA) with sensor open. Output “Low”
(3.3-3.7mA) with sensor shorted.

Zero and Span

Adjustment:

Non-interacting, Zero and Span ±5%.

Maximum Output

Current:

30 mA.

Power Connections:

Screw terminals, non-polar (connect either way).

Sensor Connections:

Screw terminals, non-polar (connect either way).

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Installation

Locate the Temptran near the RTD, in an area where the ambient temperature stays between
the temperature range of the output.
Connect the Temptran as shown in the wiring diagram below. The transmitter’s power and RTD
connections are designed for non-polar hook-up, so polarity is not important. The maximum
DC supply should not exceed 35 VDC. For the RTD, good connections are a must, a few ohms
of resistance in the connection could cause an error of several degrees.
The Temptran has been factory-calibrated to its marked temperature range or to a specific
RTD, do not change its Zero or Span adjustments.

Wiring Diagram

Figure 1

Power Supply

DC power supply requirements are determined by the transmitter’s minimum voltage
requirement and voltage drop across the load resistor and installation lead wires.

Example: The transmitter requires 8.5 Volts minimum. A typical 250 ohm load resistor drops 5.0
Volts @ 20 mA. Allowing a margin of 0.5 Volts for the supply permits 25 ohms of lead wire
resistance for remote installation. Totaling these, we get a minimum power supply requirement
of 14 VDC.

Using a 24 VDC power supply will take care of nearly all installations, but the transmitter will
operate at voltages up to 35 VDC.