1.0
DESCRIPTION
The TX12 head mounted temperature transmitter connects to any standard pt100
resistance sensor and converts the linearised temperature to a (4 to 20) mA signal. The
transmitter is a two wire device, and is fully configurable by the user, over a wide
temperature range, with the aid of a simple push button. This new TX12 design
incorporates additional configuration menus, allowing the user to push button trim the
transmitter output at both zero and span, ideal for trimming out sensor errors. The
transmitters advanced circuitry guaranties high stability over the wide operating ambient
temperature ranges experienced by head mounted devices.
One of the transmitters features is the program LED, which provides visual indication of
sensor fault when in normal operation and is also used to guide the operator through the
simple menus during configuration.
2.0
RECEIVING AND UNPACKING
Please inspect the packaging and instrument thoroughly for any signs of transit damage.
If the instrument has been damaged, please notify your supplier immediately.
3.0
SPECIFICATION @ 20 °C
INPUT
Sensor Type
PT100 100 R @ 0°C 2 or 3 Wire
Sensor Range
(-200 to +850) ° C (18 to 390) _
Sensor Connection
Screw terminal
Minimum span (see note 1)
25 °C
Linearisation
BS EN 60751(IEC 751) standard / JISC1604
Accuracy (see note 2)
±0.1 ° C±0.05% of Reading
Thermal Drift
0.0025 % / °C
Excitation current
< 200 uA
Lead Resistance effect
0.002 ° C/ _
Maximum lead Resistance
20 _ per leg
Note 1
Any span may be selected, full accuracy is only guaranteed
for spans greater than the minimum recommended span.
Note 2
Basic measurement accuracy includes the effects of
calibration, linearisation and repeatability
OUTPUT
Type
Two wire (4 to 20) mA sink
Limits
Low 3.8 mA ; high 21.5 mA
Accuracy
±(mA out / 2000) or ±5 uA which ever greater
Loop Effect
± 0.2 uA / V measured @ 50 Hz 1 V (peak to peak)
Thermal Drift
± 1 uA / °C typical ; ±1.5 uA Max
Max Load
[ (Vsupply – 10)/20 ] K_
GENERAL
Update Time
0.5 Seconds
Response Time
1 Second to reach 90% of final value
Start up time
From power up typically 5 Seconds
Filter Factor
Adaptive
Ambient Temperature
(-40 to 85) °C
Connection
Screw Terminal
Approvals
BS EN 61326 ; 1998 – Electrical equipment for measurement
and control ANNEX A ; ANNEX F
Factory Default
(0 to 100) °C upscale burnout (0.0 °C user trim)
4.0
INSTALLATION AND WIRING
Figure 1
Mounting holes : two holes 5.5 mm diameter, 33 mm centres
Centre Hole sensor wire entry : 4 mm
4.1 Mechanical
The TX12 transmitter has been specifically designed to fit inside a DIN standard probe
head enclosure (such as the Status SCH-4 series), which provides adequate protection
from moisture, dust, corrosive atmosphere etc. All cable entries must be sealed using the
correct size gland. Likewise any probe assembly fitted must be sealed.
Care must be taken when locating the transmitter to ensure the working ambient
temperature range of (-40 to 85) °C is not exceeded. The TX12 enclosure has a centre
hole allowing the sensor wired to enter screw terminals from the transmitter centre, this is
applicable when the sensor is mounted directly below the transmitter.
4.2 Electrical
Electrical connections to the transmitter are made to the screw terminal provided on the
top face. The sensor wires must be equal length and type for the lead compensation to
work correctly. The screw terminals allow for wires to enter either inner or outer direction.
The transmitter is protected against reverse connection and over voltage. If no sensor
(input) connection is made the transmitter will go into either up or down scale output
current, depending on configuration.
Figure 2 gives connection details, the output is shown connected to a 24 V supply. The
load symbol represent any other device connected in the loop, such as Monitoring
equipment , panel indicators and loop isolators. The load value can range from 0 ohms to
the max loop load for given supply, refer to section 3 “Max load” for more information.
The transmitter conforms with EC directive BS EN 61326 : 1998 when correctly installed
in a termination head providing at least IP20 protection and with sensor wires less than 3
metres. Screened or twisted pair wires are recommended for output wires. Always ensure
the (4 to 20 ) mA loop is grounded at one point, this would normally be at the monitoring
equipment or loop power supply.
In normal operation the program LED acts as over-range LED.
Figure 2
33.0 mm
CENTRES
Ø 43.0 mm
21.0 mm
SIDE VIEW
BASE VIEW
TX12
M4561/0807
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INSTRUCTION
SHEET
5.0 USER CONFIGURATION
IMPORTANT
READ COMPLETE SECTION BEFORE ATTEMPTING CONFIGURATION
PARTICULAR CARE SHOULD BE TAKEN REGARDING TIMEOUTS IN MENU 2 & 3
Figure 3 Configuration circuit
User Configuration
User configuration uses three menus, each menu sets a different parameter:-
Menu 1
Set range
Menu 2
Set direction of output on sensor burnout
Menu 3
User trim at 4 mA and 20 mA.
The configuration menus are navigated using the push button and program LED, The
push button is located under the hole in the keyhole shaped wiring label. To press the
button use a 3 mm screw driver (flat blade) inserted into the hole. The button has a slight
click action.
Three types of button press are used:-
•
Single button press
= Advance
•
Double press within 0.5 seconds
= Escape or change direction
•
Press and hold button > two seconds
= Enter
•
When a menu is selected the Program LED will flash in bursts of one to three flashes, the
number of flashes represents the menu number.
Navigating the menus
•
To access menus, press and hold button > 2 second, then program LED will start
to flash, one flash every burst. This Indicates “menu 1” is selected.
•
Use single button press to advance selection to “menu 2”, the program LED will
now show two flashes per burst. The Next single presses will advance the
selected menu to menu 3 and the next single press will advance selected menu
back to menu 1. Repeated single presses will cycle the selected menu back
around menus 1 to 3, in the above sequence.
•
Double press button to escape from menus, and return to normal. Normal
operation can also be selected by turning transmitter power off and on. Note the
transmitter will not time out and automatically escape from menus.
Menu 1 Range configuration (No Timeout)
Configuration will require the following tools and equipment :-
•
DC Supply (12 to 30) V @ 30 mA
•
Precision resistance decade box to simulate PT100 sensor.
•
Screw driver flat blade 3mm wide
•
PT100 resistance tables
•
Current meter (user trim)
PUSH BUTTON
PT100 TX
MADE IN UNITED KINGDOM
