Analog Devices LT1260 User manual

Introduction
The LT1260 load cell surge protector provides protection to the weighing system from severe over voltage and high
power impulse currents.
The LT1260 contains unique triple stage surge protection circuitry to protect the signal, supply and shield lines. The first
stage comprises of gas discharge tubes. Three terminal gas discharge tubes are used providing superior differential and
common mode protection against conducted transients then surge protectors based on two terminal gas discharge tubes.
tage two comprises of current limiting fusible series surge resistors which in a rare case of extreme lightning or surge
event will resort to a fail safe operation. This effectively disconnects the line from sensitive electronic equipment. The third
stage comprises of a low capacitance over voltage diode clamp array. The diode array clamps fast transients to a safe
level until the gas discharge tubes turn on.
The triple stage surge protector can handle higher transients then surge protectors based on voltage clamp diodes only.
1 Features
Protects the weighing system from over voltage and high power impulse currents
Protects signal, supply and shield lines
High power triple stage surge protection
Ground clamp provided on the exterior of the enclosure
Suitable for C or DC load cell excitation voltages
IP65 Protection rating
Supports 4 or 6 wire load cells
Clear lid for easy fault finding
Shielded 6-wire connection to the load cell instrumentation
Cage clamp wire connectors
1 year limited warranty
LT1260
Load Cell Surge Protector
Manual – English 1.00

LT1260 Load Cell Surge Protector Page 2
2 Dimension & Template Drawing
3 Specifications
Enclosure:
Unit Dimensions 160x80x55mm (6.3x3.15x2.17”)
Enclosure Sealing Tongue and groove with Neoprene seal
Enclosure Material Polycarbonate (grey base, clear lid)
IP Protection Rating IP65
Electrical:
Stage 1 clamping voltage +-90V
Stage 2 series resistance <=1 Ohm
Stage 3 clamping voltage +-24V
Maximum excitation voltage (symmetrical
to ground)
22Vac or 32Vdc
Nominal excitation voltage (symmetrical
to ground)
20Vac or dc
Leakage current at 20V <10uA
Maximum surge current 5kA (8/20u )
Main earth connection External M8 tud
Connections Input/Output/ ense + Earth
Connector Ratings: (Cage clamp wire connectors)
Conductor cross section solid min 0.2mm2
Conductor cross section solid max 2.5mm2
Conductor cross section stranded min 0.2mm2
Conductor cross section stranded max 1.5mm2

LT1260 Load Cell Surge Protector Page 3
Conductor cross section solid min with
ferrule
0.25mm2
Conductor cross section solid max with
ferrule
1.5mm2
Wire stripping length 7.5mm
Gland Ratings:
Clamping/sealing range 4-8mm (0.157-0.314”) Diameter wire
Environmental Conditions:
Operating temperature -20°C to 60°C (-4°F to 140°F)
Storage temperature -40°C to 80°C (-40°F to 176°F)
Operating and storage humidity <95%, RH (non-condensing)
Weight 340g
4 Installation
The LT1260 load cell surge protector should be connected as close to the load cell or equipment been protected. For
maximum protection the LT1260 can be installed at both ends of the system. Normally the surge protector will be installed
between the junction box and the weighing equipment.
The LT1260 needs to be earthed for the protection circuitry to function correctly. Connect the external M8 stud to the
equipment earth with the minimum length of cable as possible.
The LT1260 provides both a screened earth and an isolated screen by cutting the shield to earth link on the PCB.
If remote sensing is not used as in the case of 4-wire load cells then the system needs to be re-calibrated in
order to cancel out the series resistance.
Notes:
Tighten the gland nut until the rubber touches the cable completely and then tighten the nut with ½ turn (180
degrees)
Install the LT1260 with the glands pointing downwards with cable drip loops (If the cables and load cell surge
protector is exposed to water then bend a short downward loop in all cables near the cord grips so any water
draining down the cables will drip off before reaching the load cell surge protector.
If remote sensing is not used as in the case of 4-wire load cells then the system needs to be re-calibrated in order
to cancel out the series resistance.
5 Ordering Information
LT1260 – Load Cell urge Protector
6 Website
An electronic copy of this manual can be downloaded from www.loadtech.co.za.

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7 Notice
pecifications of the products displayed herein are subject to change without notice. Infiniteq cc, or anyone on its behalf,
assumes no responsibility or liability for any errors or inaccuracies.
Information contained herein is intended to provide a product description only. No license, express or implied, by estoppel
or otherwise, to any intellectual property rights is granted by this document. Except as provided in Infiniteq's terms and
conditions of sale for such products, Infiniteq assumes no liability whatsoever, and disclaims any express or implied
warranty, relating to sale and/or use of Infiniteq products including liability or warranties relating to fitness for a particular
purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right.
The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications. Customers
using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Infiniteq for
any damages resulting from such improper use or sale.
8 Warranty
This product carries a warranty for a period of one year from date of purchase against faulty workmanship or defective
materials, provided there is no evidence that the unit has been mishandled or misused. Warranty is limited to the
replacement of faulty components and includes the cost of labor. hipping costs are for the account of the purchaser.
Note: Product warranty excludes damages caused by unprotected, unsuitable or incorrectly wired
electrical supplies and or sensors, and damage caused by inductive loads.
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