OPERATING SPECIFICATIONS
SEM203TC MKII
PUSH BUTTON THERMOCOUPLE TEMPERATURE TRANSMITTER
Mounting holes:
2 holes 0.22” (5.5mm) diameter, 1.3” (33mm) centers
Center hole sensor wire entry:
0.16” (4.0mm) diameter
Side View
1.69”
(43.0mm)
1.3”
(33.0mm)
Centers
0.83”
(21.0mm)
Base View
Figure 1
Figure 2
3.0 INSTALLATION AND WIRING
3.1 Mechanical
The SEM203TC transmitter has been specifically designed to fit inside a
DIN standard probe head enclosure (such as the Status SCH4 series),
which provides adequate protection from moisture, dust, corrosive atmos-
phere 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
SEM203TC enclosure has a center hole allowing the sensor wired to enter
screw terminals from the transmitter center, this is applicable when the
sensor is mounted directly below the transmitter.
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.
3.2 Electrical
Electrical connections to the transmitter are made to the screw terminal provided on the top
face. The correct type of thermocouple wire must be used to connect sensor, this will normal-
ly be provided as part of the probe assembly. The screw terminals allow for wires to enter either
inner or outer direction. Never attempt to unscrew the spare terminal which secures the facto-
ry fitted cold junction sensor. The terminal is fitted with a tamperproof screw to avoid acciden-
tal removal.
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, depend-
ing on configuration setting.
Figure 2 gives connection details, the output is shown connected to a 24V supply. The load sym-
bol 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, [ (V supply – 10) / 20] K
⍀
.
The transmitter conforms with EC directive BS EN 61326 : 1998 when correctly installed in a ter-
mination head providing at least IP20 protection and with sensor wires less than 3 meters. A
shielded twisted pair of wires is 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 range “R” LED acts as over-range LED. The menu LED is always off.
4.0 USER RANGING
The transmitter may be purchased pre-configured, if specified at the time of order. User ranging is
provided to allow the temperature range of the transmitter to be set to a custom range. This con-
figuration level cannot change the input type, if the input type or other parameters require change,
then please refer to the advanced configuration section. To confirm the present input type set on
the transmitter is correct for y our application, count the number of flashes of the range “
R
” LED at
power up then refer to the chart in section 5 “Menu 1” to establish the type set.
The push button is located under the slot in the key hole label, the slot located next to the menu
“
M
” LED. To press the button use a 3 mm screw driver (flat blade), inserted into the slot and
locate resistance of button key. The button has a slight click action.
It may be worth noting at this stage that the advance user configuration provides the user with
the option of selecting fixed ranges, this may be a more attractive option if a suitable range is
available, as no calibration equipment will be required.
Configuration will require the following tools and equipment:
• DC Supply (12 to 30) V @ 30 mA
• Thermocouple calibrator
• Thermocouple compensating wire
• Screw driver flat blade 3 mm wide
To re-range the temperature scale follow the following instructions:
• Connect thermocouple calibrator to SEM203TC input terminals using correct thermocouple
compensation wire. Observe polarity.
• Connect the output terminals to the DC supply, observe polarity.
• Turn DC supply on.
• Set calibrator to the required low scale temperature. Note Range “
R
” LED if on indicates
input connection error or input out of range, please check input.
1.0 DESCRIPTION
The SEM203TC MKII is an in-head (4 to 20) mA transmitter that connects to a standard thermocouple sensor
and converts the sensors temperature to a linearized temperature (4 to 20) mA signal.
The transmitter sensor type and range can be requested at the time of order, but if desired the user can re-
configure the transmitter parameters by use of a single push button and the range “R”, menu “M” LEDS. Two
methods of configuration are available, the first “USER RANGING” acts only on the transmitter range, sim-
ilar to the previous SEM203TC design. The other method “ADVANCED USER CONFIGURATION” offers full
configuration. This level is entered by holding down the push button on power up. The advanced level has
the following menus:
• Menu 1 - Selection of input type, seven popular thermocouple or mV input.
• Menu 2 - Select either user push button set range or one of seven fixed ranges.
• Menu 3 - Select either up or down scale output on sensor burnout.
• Menu 4 - User trim allow trim of output current at high and low range.
• Menu 5 - Reset factory default.
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