Bulletin E-90-659TH
Series 659TH-1 Push Button Temperature Transmitter
Specifications - Installation and Operating Instructions
Ø3/16 [4.76]
Ø1-41/64 Ø1-5/16
[41.67] [33.32]
The Series 659TH-1 transmitter connects to a thermistor sensor
and produces a 4-20 mA signal that is linear with temperature. It
is suitable for in-head mounting or DIN rail with the addition of
RMK-2 clips.
An LED provides visual indication of sensor fault and programming
mode. The transmitter is simply ranged and calibrated on the
bench by using a single on-board push button switch, without the
need for soldering links. Digital technology ensures accurate and
drift free linearization to common curves.
This transmitter has been specifically designed to be mounted
inside a DIN Standard probe head enclosure, which must provide
adequate protection from moisture, corrosive atmosphere, etc. All
cable entries should be sealed using the correct size cable gland.
Care must be taken when locating the transmitter to ensure the
ambient temperature will remain inside the specified range of -4 to
158°F. The diagrams show the mechanical layout and a typical
application of the transmitter mounted inside a probe head
enclosure, with sensor wires entering through the center hole.
Figure 1
Input Types Available: 22521 common thermistor resistance
curve having a ratio of 9.7 between 0 - 50°C.
Max. Excitation Current: 2251, 240µA.
Range: -13 to 257°F.
Minimum Span: 10°F.
Burnout: Upscale 22 mA (Downscale preset current to order).
Sensor Lead Length: <18’ to 710’ to maintain CE compliance.
Sample Rate: 500 mS per reading.
Accuracy: ±0.25°F within 32 to 212°F; ±0.35°F within -13 to
257°F (0.1°C within 0 to 100°C).
Thermal Drift: Zero ±0.01°F/°F; Span 50 ppm.
Connections: Screw Terminals.
Output: 4 to 20 mA, 2 wire loop powered.
Maximum Output Range: 3.8 to 22 mA.
Operating Voltage: 8 to 30 VDC.
Accuracy: ±5µA.
Thermal Drift: ±1µA/°F.
Response Time: 500 mS to reach 70% of final value.
Loop Resistance: 8001 @ 24 VDC.
Loop Sensitivity: 0.4µA/volt.
Loop Noise: ±0.001µA.
Protection: Reverse Polarity Protected.
Connectors: Screw Terminals.
Input/Output Isolation: Not Isolated.
Warm-up Time: 2 minutes to full accuracy.
EMC: Emissions, BS EN61326; Susceptibility, BS EN61326.
Ambient Temp. Range: -4 to 158°F.
Ambient Storage: -40 to 176°F.
Ambient Humidity: 0 to 95% (Non-condensing).
Dimension: 1.9˝ (43 mm) Diameter - 0.83˝ (21 mm) Height.
Weight: 25 g.
Default Range: 0 to 100°C.
Phone: 219/879-8000
Fax: 219/872-9057
e-mail: [email protected]
Page 2
Connections to the transmitter are made to the screw terminals
provided on the top face. To maintain CE compliance, input wires
must be less than 10 ft in length and output wiring must be
shielded cable grounded at one end only. A hole is provided
through the center of the transmitter body, direct to the input
screw terminals. The screw terminals have been designed to allow
all connection wires to enter from either an inner or outer direction.
The transmitter is protected against reverse connection, therefore
incorrect connection of the output wires will result in near zero
current flow in the loop. Incorrect connection of the sensor wires
will result in the transmitter output going to burnout condition.
Figure 2 shows the method of connection to provide a 4-20 mA
current loop output. The Platinum resistance sensor shown would
normally take the form of a probe assembly with a three wire
output. The output loop shows a 24 VDC power supply, used to
provide loop excitation, the transmitter, and a load, all connected
in series. The load symbol represents other equipment in the loop,
e.g., indicators, controllers, loggers, etc.
Figure 2
The following apparatus will be required in order to re-range the
• Power supply voltage between 10-30 VDC, 30 mA min
• Precision resistance box.
• Connecting cables.
• 3 mm diameter screw driver or similar device.
• Current meter 0 - 20 mA to monitor loop current.
• Thermistor tables.
Refer to Figures 1 and 2 for correct connection and type setting
details, this information is duplicated on the transmitter side label.
1. Connect circuit as shown in Figure 3 and set the Resistance
Box for temperature required at 4 mA.
2. Press and hold the programming switch by inserting a 3 mm
diameter screwdriver blade through the programming hole,
located in the top face of the transmitter housing. Hold the switch
for approximately 5 seconds, until the RED programming LED
flashes. Release the switch.
3. Set the Resistance Box for the required temperature at 20 mA.
Allow 10 seconds settling time, then press and release the
programming switch. The programming LED will flash quickly for a
few moments, then go out. The transmitter is now ranged.
4. Check that the transmitter output range is correct by setting the
Resistance Box to the 4 mA and then 20 mA settings, checking
the output current reading on the meter.
Calibration Circuit
Due to sensing method, certain combinations of open circuit
sensor wires may result in the output current dropping for
approximately 500 mS, before rising to upscale output.
Care must be taken when designing the 4-20 mA circuit to ensure
that the total burden of the loop, that is the total voltage
requirements of all the equipment in the loop added together, does
not exceed the power supply voltage. If a number of devices are
connected in the loop, ensure that only one instrument is tied to
ground. Grounding the loop at two points will result in shorting out
part of the loop and therefore any transmitters in that part of the
loop will not operate.
Maximum load resistor, RL, is calculated as follows:
RL = (v-8)/20 x 1000
For 24V supply:
RL = (24-8)/20 x 1000 = 8001
This transmitter conforms with EC directives BS EN61326 when
correctly installed in a termination head providing at least IP20
protection and fitted with a sensor with less than 10’ (3 m) of
Figure 3
Upon final installation of the Series 659TH-1 Push Button
Temperature Transmitter and the companion receiver, no routine
maintenance is required. A periodic check of the system
calibration is recommended. The Series 659-TH1 is not field
serviceable and should be returned if repair is needed (field repair
should not be attempted and may void warranty). Be sure to
include a brief description of the problem plus any relevant
application notes. Contact customer service to receive a return
goods authorization number before shipping.
This transmitter is normally supplied ranged 0 to 100°C, unless a
special range has been requested at the time of order. With the aid
of suitable equipment, this transmitter can be programmed to a
different range by following the simple procedure listed below.
©Copyright 2005 Dwyer Instruments, Inc.
Printed in U.S.A. 5/05
Phone: 219/879-8000
Fax: 219/872-9057
e-mail: [email protected]
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