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Instruction manual for use of TRA-104D transmitters
Transmitter is designed for measurement of air temperature at °C or °F and relative humidity of
air without aggressive ingredients with computing one of the following values: dew point
temperature, absolute humidity, specific humidity, mixing ratio and specific enthalpy. Instrument is
equipped with an external humidity and temperature probe on a cable. The probe is a non-
removable instrument part. Measured and computed values are displayed on dual line LCD display.
The first line displays temperature. Value displayed on the second line is selectable among relative
humidity and computed value. It is also possible to display both readings with cyclic overwriting in
4 seconds interval. It is possible to switch OFF the LCD at all. Transmitter is connected to circuitry
by means of one or two galvanic isolated loops. Each loop has two-wire connection and each loop
requires power from evaluation device. It is always necessary to connect current loop I1 for proper
transmitter function (from loop I1 part of the transmitter is powered). If current loop I1 is opened or
disconnected, then loop I2 and LCD will not work. It is possible to assign measured value to current
loop output I1 or output I2 (both two-wire connection). Please read instruction manual before the
first device connection.
All transmitter setting is performed by means of the PC connected via the optional communication
cable (not included in delivery). Program Tsensor for transmitter setting is available at Atal.
Program enables to assign each current loop output measure value (temperature, relative humidity,
computed value) and its range. It supports make the adjustment of the device too. This procedure is
described at file „Calibration manual.pdf“ which is installed commonly with the software. It is also
possible to assign both outputs to the same value (with the same range), if two evaluation devices
are necessary to connect.
Device setting from the manufacturer
Transmitter is set from the manufacturer to the following parameters:
value at output I1: relative humidity, range 4 – 20 mA corresponds 0 to 100 % RH
value at output I2: temperature, range 4 – 20 mA corresponds -30 to +105 °C
display: switched ON
value displayed at line 2: relative humidity only
Modification of the setting is possible to do by means of the PC using procedure described
at the end of this document.
Installation of the transmitter
Transmitter case with electronics is designed for wall mounting. It is NOT recommended to
use the probe for long time under condensation conditions. It could be the cause of water steam
condensation inside the sensor’s cover into water phase. This liquid phase stays inside sensor’s
cover and can’t escape from the cover easily. It can dramatically increase response time to relative
humidity change. If water condensation occurs for longer time it can cause sensor damage. Similar
effect can occur under water aerosol conditions. If this effect may occur, it is necessary to use the
probe at operation position with sensor cover downwards. Don’t connect transmitter while power
supply voltage is on. Interconnection terminals are accessible after unscrewing four screws and
removing the lid. Lace the cable through a gland at the case wall. Connect the cable to terminals
with respecting the signal polarity (see figure). Terminals are self-clamping and can be opened by a
suitable screwdriver. For the opening, insert the screwdriver to upper terminal hole and lever by
him. Do not remember to tighten glands and case lid with inserted packing after cables connecting.
It is necessary for warranting of protection IP65.
It is recommended to use shielded copper cable (e.g. SYKFY) with outside diameter of the
cable must be from 3.5 to 8 mm, maximal length 1200m. The cable must be located at indoor rooms
(probe is not protected for outdoor use). The cable should not be led in parallel along power