Digital Fluid Damped
Single Point Load Cell
• Fully Calibrated, filtered digital output
• High A/D update rates (adjustable from 50 to 800
• Readings on request OR continuously output• Checkweigher function-reading acquired over period
• Configurable filtering• Safeguarded access to calibration for approved
• EMC compliant and surge protected• Extensive on board diagnostics with error log• Visual indication of operating mode and fault conditions
Fluid damped and overload protectedAuto detect communication
Model Digital 240 is specifically designed for high speed/
Communication is straightforward using an ASCII command
dynamic weighing. Fluid damping vastly improves its
structure and high update speeds are possible, making it
response time and fatigue life over undamped load cells.
particularly suitable for check weighing.
On board electronics make it highly configurable and simple
In multi-head weighing machines, up to 12 units can be
to employ in approved weighing applications.
networked together over an RS485 link. The load cells
A wealth of application experience has gone into this load
initialize automatically and arbitrate between themselves to
cell to allow weighing system designers to speed
create a working network. This removes much difficulty at
development of their own designs - a great proportion of the
set up and means that load cells can be changed over in
functionality required to create a fully featured weighing
service as ‘plug and play’ units: - Factory calibration ensures
system is already implemented in the digital 240.
that each unit will be virtually identical in performance.
Fluid damped & overload/underload protected
Maximum Dynamic Load
Operating Temperature Range
Protection Class (EN6059)
*1, 2, 3 & 90Kg not OIML approved.
Current Consumption (maximum)
Load Cell Excitation Voltage
Update Rate (ADC)
Maximum Cable Length
Maximum Number of Network Devices
Cable to be ordered separately standard 3 meter cable, Part Number. 3-1437-720-4.
COMMUNICATING WITH THE DIGITAL 240
The Digital 240 has a number of key features in terms ofdiagnostics foe cell operation:
The digital 240 operates in two distinct modes
1. External indication of errors - a tri-colour led is used to
show status and fault conditions. Even in the worst case,
if communication with the load cell is not possible, thedigital 240 can still give an indication of its health and set up.
A typical digital weighing installation will consist of a hostdevice (e.g. PC, digital indicator, PLC) and between 1 to 12
2. Internal error log - a time referenced log of errors is
load cells connected over a single bus and then back to the
maintained (up to 14 scrolling errors) which allows tracing
host via a single cable. Over this connection commands
of repeating fault conditions, and identification of time of
are issued by the host and the load cells respond with
3. Validity of readings - with each reading, status characters
When a network of load cells (or a single load cell) are
are transmitted (good/bad/warning). Fatal errors cause
connected together to a host device, on initialisation of the
readings to cease and error codes are transmitted.
network, the first load cell on the network will designate itself
4. Integrity of calibration - at power up the cell(s) self check
the ‘Boss’ load cell, and set up the other load cells in
‘Auxiliary’ mode, establishing communication and allocatingaddresses etc. It also performs weighing system checks,
ensuring calibration integrity and compatibility of load cells
(b) Consistency between units used in combination
(c) The network has been changed - units added/removed
In operation, the host device can as a result of the above,ignore the detail of managing all load cells, and communicatewith the Boss device only as though it were a scale. Auxiliaryload cells can, however still be accessed individually asrequired.
A significant advantage of the digital load cell is in terms ofcost of ownership. The analogue load cell, especially in multi-cell applications can be awkward to set up and fault find. Ina production line environment, the real cost of determiningand resolving equipment problems is high. Reliable andmeaningful feedback about load cell operation and faultconditions are essential for fast recovery and this is wherethe Digital 240 pays for itself.
INSTALLATION CHECK LIST
The model 240 has proved itself a consistent performer in
The Digital 240 is an accurate, repeatable instrument and to
check weighing and the Digital 240 extends its capability
realize its full performance, a number of points should be
with features specific to this application:
Mount on Flat, level (ideally ground) surface, rigid enough to
remain level under load. Isolate where possible, from sources
of vibration (Motors, random external etc). Use 4 off base
User configurable f3db = 0.14 to 195Hz Slope = 12dB/octave
plate bolts, torqued to 35-40NM (25-30lb ft).
2. Externally triggered acquisition of weight (e.g. Trigger input
from PECs). The Digital 240 allows a maximum 480Hz A/DAcquisition speed - producing a single filtered weight valueat the end of the weighing period.
LIVE END MOUNTING
• The weighing platform belt feed should be appropriate to
the maximum live weight (live weight can cause stretching
• The weighing platform assembly should be rigid enough
• Note: settling times increase with tare load.
Anything that prevents free movement of the cell under
• Use both load cap mounting bolts torqued to (12lb ft).
INFEED OF WEIGHED ITEMS
• Avoid shock application of load from:
(a) The Transportation grub screw (centre load cap vent
(a) Edge impact due to a step between infeed and weighing
(b) The under side of the load cap is free of debris etc
(b) Live weight dropped directly onto platform
(c) The filters fitted to the load cap are not blocked (special
• The path of the live weight over platform, should be through
filters/ options can be provided for corrosive atmospheres,
the centre line of the load cell (length wise).
low temperatures, high humidity/very aggressive wash down.
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Information contained herein is intended to provide a product description only. No license, express or implied, byestoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Vishay'sterms and conditions of sale for such products, Vishay assumes no liability whatsoever, and disclaims any expressor implied warranty, relating to sale and/or use of Vishay products including liability or warranties relating to fitnessfor 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 fullyindemnify Vishay for any damages resulting from such improper use or sale.
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