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IMPORTANT
•
The LCT-485 is not suitable for use in a hazardous area. It MUST ONLY be connected
in the safe area, and protected by a suitable Intrinsically Safe isolator or barrier.
•
Do not operate this unit near strong electromagnetic fields (e.g. around generators or
induction heaters). Electromagnetic interference can cause measurement errors.
•
Wires must be connected only to the appropriate terminals.
•
Do not open the LCT-485 housing. This will damage the unit and invalidate the
warranty.
MAINTENANCE
Our customer service representatives are available for application assistance, calibration,
repair, and solutions to specific problems. Contact our Service Department before returning
any equipment. In many cases, problems can be solved over the telephone. If the device is
not performing as it should, try to match the symptom below to the problem. If the table does
not help, contact us for further advice.
TROUBLESHOOTING
Symptom
No communications
No (or intermittent)
communications
GUARANTEE
Calex guarantees each instrument it manufactures to be free from defect in material and
workmanship under normal use and service for the period of two years from the date of
purchase. This guarantee extends only to the original buyer according to the Calex Terms and
Conditions of Sale.
Calex Electronics Limited
PO Box 2, Leighton Buzzard, Bedfordshire, England LU7 4AZ
Tel: +44 (0)1525 373178
Email: mail@calex.co.uk
8
Probable Cause
No power to the
device
Incorrect Modbus
Slave address
Modbus Slave address
conflict
RS-485 network layout
incorrect
No termination
resistors
Fax: +44 (0)1525 851319
Online: www.calex.co.uk
Solution
Check the power supply and wiring
Check the Modbus Slave address on the
label on the side of the unit. Check if the
Modbus Slave address has been changed.
To read the Slave Address via Modbus:
With only one LCT-485 unit connected to
the Modbus Master, read from register
0xD0 using Slave address 255 (this will
produce a response from any Slave address)
Ensure each unit on the network has a
unique Modbus Slave address
Ensure each RS-485 device is attached with
as short a cable as possible to the main
network bus
Ensure there is a 120 Ω termination resistor
connected between the RS-485 + and - lines
at the Modbus Master, and another at the
end of the bus at the farthest device
Issue B - Oct 20
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