Load Cell Amplifier with Relays Data Port & Display for Weighing (LA20LR1S1PLTL)


  • Play LCA20 video to learn more about the features
  • Full digital set–up using PC or keypad
  • 3 x configurable digital inputs e.g. for autotare, peak hold and reset
  • RS485 and RS232 digital data output for communications and printing
  • Measurement speeds of 10 / 80 samples per sec
  • Factory calibration in mV/V
  • 5 V excitation supports up to 10 x 350 R load cells
  • Fully isolated 4-20 mA and 0-10 V analogue outputs
  • 6 wire input to compensate for barrier and cable losses
  • 2 set points SPCO relay outputs
  • Sensitivity from 0.5 to 7.8 mV/V
  • 10 pt linearization
  • Firmware now supports Mantrabus 1 & 2, MANTRA ASCII 2 & MODBUS RTU
  • ROHS Compliant & Environmentally sealed to IP65 / NEMA 4 enclosure dimensions 200 x 120 x 75 mm
  • Supplied in IP65 NEMA4 ABS protected case, stainless steel version or DIN Rail option.
  • The LCA20 shown in main photo has the transparent lid option (LTL)
SKU: LA20LR1S1PLTL Category: Tag:


This very flexible digital load cell amplifier for weighing single or multiple load cell applications, offers an easy one-pass calibration and fast setup.  It is also equipped with relays, data port and display.

The LCA20 load cell weight indicator offers options of local or remote LCD displays, isolated 4-20 mA 0-10 V analogue outputs, relay outputs for control or alarm functions, for example, in crane overhead alarms, and also for, in-flight compensation commonly used in silo bag filling applications. The RS232 or RS485 options provide for digital communications (including setup) and can support label or ticket printers.

Analogue and digital output, set point and display capabilities AC or DC powered, IP65 NEMA 4 protected.

The LCA20 (load cell amplifier) replaces the LCA15 and provides increased functionality, improved performance and takes advantage of new technology. See the migration sheet for further details.

Need to know more about our load cell amplifiers? See our comprehensive information and application suggestions Load Cell Amplifier

View LCA20 Video on YouTube to learn more.

Can be used in conjunction with our LCI load cell failure alarm, which is designed to continuously monitor the condition of individual load cells and activate an alarm when faults in the system are detected, therefore providing increased safety and cost savings onsite for all weighing systems.


TitleVersionSizeHitsDate addedDownload
LCA20 Product Sheet599.16 KB66324-05-2021 DownloadPreview
LCA20 Manual01.053.44 MB73624-05-2021 DownloadPreview
Download LC Toolkit Software1.10.07.24 MB22225-05-2021 Download

Version 1.9.0 The LC Toolkit software for Windows will allow a connection with the LCA20 via an optional on-board communications module LC4 or via an optional programming cable PGM1.

Q: What Protocols are available with the LCA20?

A: There are 4 Protocols
CP=128 = Mantrabus 1 a hex based protocol. Most popular, easiest to deal with from programming point of view.
CP=131 = Mantrabus 2 updated version of Mantrabus1
CP=133 = Mantra ASCII 2 based protocol designed for old teletype machines, looks easier but actually more complicated to programme.
CP = 132 Modbus RTU used a lot in PLCs. 3rd Party S/W available. Hex based.
Or alternatively set CP=127 and the device will transmit an ASCII string every display update (used for continuous printout to either printer or display.

Q: Does stainless steel case for LCA20 have stainless steel glands?

A: No plastic PG9 glands.

Q: Does the 4-20 mA output on an LCA20 have galvanic separation?

A: No but it does have electrical isolation up to ±130V RMS

Q: How do you view the live reading on the LCA20 without Auto Tare and having to calibrate again?

Go to the ‘measurement’ section in the LCA Toolkit.
Note the reading in the ‘Tare’ value box and then change the value to zero. Click on the ‘Tare’ button and the unit will display live reading.

Alternatively, using the keypad:
Go into the menu and pick AT Mnemonic.
Note the reading down and then set to zero.
Press return and then the unit will display live reading.
To reset Auto Tare re enter value in AT Mnemonic screen which you noted down.

Q: What is the maximum length of cable we could connect between a LCA20 unit and a load cell unit?

A: It would depend on many different factors:
The quality of the cable
The type of cable
Whether it was 4 or 6 core
The number of load cells
With the best quality of cable in an ideal environment and with little or no interference we have had operating at 200 metres.

Q: LCA20 / SMW can they handle tension and compression?

A: Yes

Q: Is it possible to connect two LCA20s to one load cell?

How would the scaling of each remain stable in the event of a failure of one or the other ?
Can the output of the load cell be connected to both LCAs? With perhaps a resistor network holding the input of the second to a reference ?

A: This is done using 6 wire, with the second LCA20 as 5 wire (no “+” excitation).
You could have two 6 wire with two blocking diodes (for redundancy).
Or a separate power supply and two 5 wires.

Q: How do I factory reset a ADP / ADW / LCA20 / SMW?

A: Hold down the Scroll and reset key and then power cycle the unit.

Q: Can I use a laptop to set up the LCA20?

A: Yes, by means of the optional PGM1 Programming Cable and the LCA Toolkit. The option to use the LCA20 keypad is also available.

For more ‘Frequently Asked Questions’ please see our Knowledge Centre

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