Temperature Transducer

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2 wire 4...20mA connection
Wide operating range
Low price
0.5% accuracy

Temperature Transducer
MODEL: TT-R-100

The TT-R-100 is used to convert a platinum RTD temperature sensor to a 4-20 mA signal to interface with your energy management panel. The output is proportional over a selected span.

The resistance change of the RTD passes through a bridge to the amplifier and is converted to a proportional d.c. current in the output stage. The output current is controlled through a feedback circuit and thereby becomes independent of load. A diode protects against reverse polarity. This technology is field proven and has been capable of withstanding rigorous environmental chamber testing while retaining linearity without damage.

This technique produces a very reliable system with good accuracy at an excellent price.

Temperature Transducer - Technical Data

Stock Ranges:

-50 to +50°C
0 to +35°C
0 to +50°C
0 to +100°C

Models:

TT-BB-R-100	Bare Circuit Board
TT-ST-R-100	Snap Track Mounted
TT-DR-R-100	DIN Rail Enclosure

Initial Calibration:

± 0.2%

Linearity:

± 0.1% of span

Operating Temperature:

-20 to +70°C

Temperature Drift:

Less than 0.012% Span / °C

Supply Voltage:

5 to 30 Vdc (nominal)

Supply Voltage Error:

0.01% max of fullscale per volt deviation from 24Vdc

Maximum Load:

(Vsupply-12)/20mA

Load Error:

0.02% max of full scale per 100 ohms

Output:

4 to 20mA in 2-wire technology

Temperature Transducer - Installation & Operation

Temperature Sensors

Installation

All Enercorp thermistor temperature sensors are unaffected by polarity or position. Units with time over-ride (TOS) or setpoint over-ride (SS) features have labelled terminal blocks. All other versions are supplied with 22 awg leads.

Troubleshooting

Problem	Cause
Sensor reads 0 or only a few ohms	Sensor or leads are shorted
Sensor reads over full scale or very high	Sensor or leads are open
Readings are erratic	Loose connection

Calibration

These sensors have no built-in means of calibration. Minor adjustments must be made at the receiving instrument or DDC panel. If an adjustment of more than a degree is required first check your connections. If the connections are good the sensor may have been damaged by operation outside it's temperature range or mechanical causes. Damaged sensors can not be repaired and must be replaced.

RTD Temperature Transmitters

Installation

All Enercorp RTD temperature transmitters are unaffected by position, are reverse polarity protected and supplied with a two pole terminal strip.

Troubleshooting

Problem	Cause
No reading	1. Lead wires are reversed 2. No power to board - check voltage is between 13 and 30 VDC
Reading too low or too high	1. RTD wires shorted or RTD defective. Check that RTD resistance is about 100 ohms + 0.4 ohms/degree C above 0 C. 2. Check for correct transmitter range. 3. Check for condensation or mechanical damage to board.
Readings are erratic	Loose connection. Screw down all connections tightly.

Calibration

These transmitters have clearly marked zero and span pots. To calibrate connect a precision decade box to the RTD terminals. Since 1 degree Fahrenheit change is equal to a 0.2 ohm change you need a very accurate decade box to calibrate accurately. Insert a DVM set to mA in the 2-wire loop and apply power. With the decade box set to the scale beginning resistance from the table adjust the zero pot to obtain 4 mA. Change the resistance in the decade box to the scale end and adjust the span pot as necessary to obtain 20 mA. Go back and forth until the readings are stable.

°F	Ohms	°C	Ohms
-50	82.08	-50	80.32
0	93.03	0	100.00
100	114.68	35	113.61
125	120.04	50	119.39
250	146.48	100	138.50
400	177.48	200	175.84
750	246.68	400	247.06

Temperature Transducer - Ordering Data

TT-	(	Model	)	-R-100/	(	Range	)
		BB = Bare PC Board				Stock values:
		ST = Snap Track				-50+50C
		DR = Din Rail				0+35C
						0+50C
						0+100C

e.g. TT-ST-R-100/0+35C	Temperature transmitter mounted on snap track with 0 to 35°C temperature range
e.g. TT-P-4-R-100/-50+50	4" pipe RTD sensor with -50 to +50°C temperature sensor built-in.

Temperature Transducer - Downloads

Data Sheet

Installation & Operation

All files are in PDF format and may be read with Adobe Acrobat Reader

Temperature Transducer