Omega TX12, PT100 TX - Push Button Instruction Manual

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.

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.

SPECIFICATION

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

INSTALLATION AND WIRING

SIDE VIEW

BASE VIEW

Mounting holes: two holes 5.5 mm diameter, 33 mm centres Centre Hole sensor wire entry: 4 mm

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.

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.

USER CONFIGURATION

READ COMPLETE SECTION BEFORE ATTEMPTING CONFIGURATION PARTICULAR CARE SHOULD BE TAKEN REGARDING TIMEOUTS IN MENU 2 & 3

User Configuration

User configuration uses three menus, each menu sets a different parameter:-

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:

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)

Menu 2 Burnout Selection (Timeout is 3 Seconds)

• Refer to figure 3, Connect output to a DC supply, observe polarity. For this menu the input can be connected or open circuit. Turn power on.
• Press and hold button > 2 seconds to enter menus, menu 1 will then be selected, indicated by one flash every burst.
• Single press button to advance selection to menu 2, indicated by two flashes of the program LED every burst.
• Whilst menu 2 is selected, press and hold button > 2 seconds to enter menu 2, at which stage the program LED will either toggle on and off at a slow indicating low scale burnout or fast rate indicating upscale burnout.
• To change burnout direction single press button. The Program LED toggle rate will change to the other setting. Repeated single presses will toggle between up and down scale.
• To store setting allow 3 seconds with no button action, the program will then timeout, store new setting then return to normal operation.

Menu 3 User trim (Timeout is 20 Seconds)

This menu allows the user to trim the output current at 4 mA and 20 mA points, (similar function to trim potentiometers) and is very useful for trimming out sensor errors.

The input of the transmitter must be connected to either a calibrator or temperature sensor held at a known temperature. The (4 to 20) mA loop current also need to be monitored with a current meter.

• Refer to figure 3, connect sensor or resistance box to TX12 input terminals using three wire connection. Connect output to a DC supply, observe polarity, connect current meter in series with loop. Turn power on and allow 1 minute warm period.
• Set calibrator to the equivalent resistance of the PT100 sensor, at required point. Alternatively ensure sensor temperature is at the required calibration point.
• The transmitter will automatically trim the 4 mA end if the output is within the active band of (3.8 to 6) mA, and trim the 20 mA end if the output is within the active band of (18 to 21.5) mA. No setting adjustment is performed if the output current not within these two bands. Ensure your calibration points are within these bands.
• Press and hold button > 2 seconds to enter menus, menu 1 will then be selected, indicated by one flash every burst.
• Single press button to advance selection to menu 2, and single press again select menu 3 indicated by three flashes of the program LED every burst.
• Whilst menu 3 is selected, press and hold button > 2 seconds to enter menu 3, which stage the program LED toggle on and off at either a slow rate indicating downward trim direction or fast rate indicating upwards trim direction.
• To change trim direction double press button. The Program LED toggle rate toggle to the opposite direction. Repeated double presses will toggle between and down trim direction
• To trim output current, single press button to advance current 2 uA in set direction, or press and hold button to auto advance in set direction release button to stop advance. Note after approximately 20 seconds of continuous button press, auto trim rate will speed up. Monitor the current change on the current meter.
• To store new setting allow 20 seconds with no button action, the program will then timeout, store new setting then return to normal operation.

Reset to factory default settings

If required the SEM203P can be reset to factory default setting, this procedure also removes any user trim adjustment. Factory default settings are:

To reset to factory setting, hold the button down whilst the TX12 is powered up.