PT113
Instruction Manual
8
to complete the mechanical installation of your weighing system and the panel is finalised to ensure
best reliability before starting the electrical installation as described below.
4.3 CONNECTING THE LOAD CELL
Warning:
After load cell connection to the instrument, any welding on the mechanical constriction is not
recommended. Disconnect all connectors from the instrument before any welding on the mechanical
hardware.
The load cell wiring should be installed carefully before energising to avoid damage to the instrument
and load cells. The combined input resistance of the load cells that you want to connect should be more
than 58Ω (6x 350Ω or 12x 700Ω load cells). Do not bind the load cell cables together with other cables
as it could result in cross-talk interference. Please also keep them well away from the AC power cables.
4 wire LC connection
6 wire LC connection
Load cell connection details are shown above. In 4-wire installations the sense and excitation pins with
the same polarity should be connected together in the connector (connect Sense+ to Exc,
Sense- to Excitation-). If you have a junction box in your system, use 6 wire cable between the
instrument and the junction box, and for 4 wire load cells connect Sense and Excitation in the junction
box for better performance.
Warning:
Always connect Sense pins to Excitation pins for 4 wire connection. Non-connected sense
pins may cause the wrong Excitation voltage measurement and create an accuracy problem.
Warning:
Connect the load cell cable shield to the reference ground or shield pin of the load cell
connector.
4.4 POWER SUPPLY AND GROUNDING
The weighing instrument measures very low signal levels. The quality of the power supply and
grounding will affect the accuracy and the safety of your measuring system. It is very important that the
instrument should not share power lines with noise-generating parts such as heavy load switching
relays, motor control equipment, inductive loads, etc. If the condition of the mains power supply in the
plant is poor, install a special mains power line and grounding.
The power supply voltage of the instrument shall be between 11 VDC and 28 VDC. The connection of
power supply to the 24 VDC power supply connector is shown in 4.2.1CONNECTIONS. Be sure, the
power supply is switched of before connection.
Warning
:
Before modifying the instrument, turn the power off and wait at least for 30 seconds.
Warning:
Connect the power supply grounding
pin to the reference ground.
4.5 FIELD BUS CONNECTION
Refer to the following sections for the appropriate fieldbus connection.
9.1 PT113MB, PT113EN - Modbus
9.2 PT113PB – Profibus
9.3 PT113PN - Profinet
9.4 PT113EI - Ethernet/IP
9.5 PT113CO – CANopen
PT are developing a Technical Note TN 16.779 Software and Communication with Azure Series
Instruments to assist with field bus communication set up.
4.6 ENERGISING THE INSTRUMENT
Check the mechanical installation, grounding, load cell connection and power supply connection to be
sure correct electrical installation has been completed before energising the instrument. If all previous
steps have been completed properly, energise the instrument.
