Flintec LAC 74.1 User Manual

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Page 1

FLINTEC ...the right weigh

Analogue Amplifier Type LAC 74.1

MANUAL

Off

0,5

2,0

1,0

%at 2mV/V

SET ZERO Pot ccw = calib.

2,5

FLINTEC

LOAD CELLS 10Vdc 120mA

Exc

Inp Inp Sen

Sen

+++

4,0

8,0

16,0

Exc

Relative gain

Resolu.

1000 n

Pol. +/-

Fine adj.

SET SPAN Pot ccw = calib.

1,0

0,25

Out

20mA/ 10V

Gnd

0,5

1,0

2,0

4,0

8,0

16,0

Fine adj.

CUT

SET

3,3

FILTER

160

0,33

500

0-20/4-20

20mA/10V

OUTPUT

In range.

Under

Over

CND

Error

Pwr. OK

LAC 74.1

Log Err.

Gnd

I/V

PWR

12-24Vdc

GND

Document No G133 Rev2 UK

www.flintec.com

Manual LAC 74.1 Page 1

Page 2

...the right weigh FLINTEC

LAC 74.1 Specifications

Linearity < 0.01 %

Analogue input range

Excitation 10 V DC, for up to 4 load cells 350 Ohm, 6 wire technique

Safety circuit

Zero adjustment (Offset) ±3 mV/V, zero adjustment by DIP switches and fine trimming potentiometer Current output Voltage output Input filters 0.33 ... 33 Hz, DIP switch selectable (5 steps) Temperature range –20 °C to +50 °C (operating); –20 °C to +60 °C (storage)

Temperature effects

Enclosure

Power supply

All dimensions in mm. Dimensions and specifications are subject to change without notice.

±0.1 mV/V to 3.5 mV/V, gain adjustment by DIP-switches and fine trimming potentiometer

Logic output, Open Collector, normally closed, opens in case of error (max. 30 V DC, 300 mA):

- Load cell input- or sense wires signals are out of range

- The current or voltage output is out of range

-Powerfail

0 ... 20 mA or 4 ... 20 mA; R 0 ... 10 V; R

Load

³ 500 Ohm

Load

³ 500 Ohm

on zero 25 ppm/°K on span 50 ppm/°K

135 x 66 x 18 mm, protection IP40, for standard 35 mm DIN-rail mounting, (special housing on request)

12 ... 24 V DC ±10% or 12 ... 18 V AC, 3 W max., reversed polarity and excess voltage protected

System Configuration

0,5

2,5

Off

%at 2mV/V

SET ZERO Pot ccw = calib.

FLINTEC

LOAD CELLS 10Vdc 120mA

Exc

Inp Inp Sen

Sen

+++

Load cells

connection

;

6-wire

1,0 5

4,0

2,0

8,0

16,0 80

Exc

Relative gain

Resolu.

1000 n

Pol. +/-

Fine adj.

SET SPAN Pot ccw = calib.

PLC and/or

computer with

analogue input

1,0

0,25

Out

20mA/ 10V

Gnd

PLC

system

0,5

3,3

FILTER

160

0,33

500

0-20/4-20

20mA/10V

OUTPUT

In range.

Under

Over

Error

CND

Pwr. OK

1,0

2,0

4,0

8,0

16,0

Fine adj.

CUT

SET

LAC 74.1

Log Err.

Gnd

I/V

Open Collector output,

normally closed,

opens in case of

LAC 74.1 error

Silo Nr.: 1

Netto : 17285 kg Tara : 1458 kg

PWR

12-24Vdc

GND

-----------------------

Power supply

12...24 V DC

14...28 V AC

Page 2 Manual LAC 74.1

Page 3

FLINTEC ...the right weigh

Calibration of the analogue output

1. Mounting the module

The SG module has to be installed in a cabinet in compliance with (inter)national electrical regulations. Connection details are printed on the upper face of the amplifier housing. The amplifier module supports 6 wire technique. If you are using a 4 wire load cell, the “Exc +” and “Sen +” terminals must be shorted together as well as the “Exc –“ and “Sen –“ terminals.

2. Adjustment settings

All DIP-switches and potentiometers are positioned near the top edge of the housing.

DIP-switches and

potentiometer

for zero setting

OFF

0,5

1,0

2,0

2,5

%at 2mV/V

SET ZERO Pot ccw =calib.

DIP-switches and

4,0

8,0

16,0

Pol. +/-

Fine adjust

potentiometer

for gain setting

Relative gain*

Resolution *1000n

SET SPAN Pot ccw =calib.

0,1

0,25

DIP-switches

for low pass filter

0.5-33 Hz

0,5

1,0

2,0

4,0

8,0

16,0

signal out of range (e.g. negative too)

signal out of range (e.g. > 2 mV/V)

fCUT

Fine adjust

SET FILTER

error message safety logic

DIP-switches for choosing analogue output 0-20 mA or 4-20 mA or 0-10 V.

3,3

0,33

160

500

input signal OK

power is ON

20mA o.10V

0-20 o. 4-20mA

OUTPUT

Over

Under

In range

= =

In range = = =

Power OK

Error

Power OK

CND

Under

Over Error

3. Setup DIP-switches

Zero setting:

The left six DIP-switches permit the off-set to be adjusted in steps of 0.5 mV throughout the range of 0 to 31.5 mV. The seventh DIP-switch sets the polarity of the zero adjustment, either Positive (ON) to make the output more positive or Negative (OFF) to make the output more negative. The 20-turn potentiometer permits fine trimming of the zero point. The total range is + or – 80%.

DIP-switch ON none 123456allPol.Pot.

Relative to 20 mV % 0 2.5 5 10 20 40 80 157.5 +/– 3

InputatZeroV

out

mV00.512481631.5+/–0.6

Span (Gain) setting:

The seven DIP-switches permit the relative gain to be set in 128 steps of 0.25x over the range 1 to 32. The 20-turn potentiometer permits fine trimming. Therefore, any input signal range between 0.1 mV/V and 3.2 mV/V can be used to generate the full scale output (0 – 10 V or 0 – 20 mA or 4 – 20 mA). Note that the higher the gain, the lower the resolution that can be obtained.

DIP-switch ON none 1234567allPot.

Relativegainfactorf10.250.5124816330.3

Inputat10VV

out

Manual LAC 74.1 Page 3

mV32302824168421xx

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...the right weigh

FLINTEC

Current output: The I

range can be set to0–20mAor4–20mA.

out

Voltage output: 0 – 10 V output only if current output 0 – 20 mA is selected.

Low-pass filter:

By combining the four DIP-switches the low-pass filter can be set from 0.33 Hz up to 33 Hz. Factory default is 33 Hz.

DIP-switch ON none 1234

Time constant ms 5 16 50 160 500

Settling time ms 40 130 400 1300 4000

Cut off frequency Hz 33 10 3.3 1 0.33

4. Output current (or voltage) adjustment

Use a digital multimeter with at least a 5 digit display. Connect to current or voltage output as appropriate. Remark: The multimeter should have a current resolution of 0.01 mA to get a calibration accuracy of 0.05%.

5. Setting Zero

With no load on the weighing system, use the Zero DIP-switches to initially set the zero value coarsely to approximately 4 mA (or whatever value you want at no load). Then use the fine zero potentiometer to make the final adjustment.

6. Setting the Span (Gain)

If you know that you will need to change the gain substantially, it is best to adjust the span DIP-switches first and then reset the zero prior to applying any loads. For instance if you are only using 40% (8 mV) ofthe load cell range (20 mV) you will needto increase the relative gain to 4x (DIP switch 5 on). See Gain table overleaf. Apply the calibration load and use the fine potentiometer to give the required result.

Stages 5 and 6 may have to repeated to achieve the required results.

7. Weighing system ready for use

The weighing system is now calibrated and ready for use.

8. Safety

If a short circuit occurs on the load cell supply wires, output wires or sense wires, the output from the LAC 74.1 will fall to zero as a fail safe condition. With the 4 – 20 mA range selected,an open circuit in the 4 – 20 mA loop will also be detected as a fault. Under fault conditions the 4 – 20 mA output will fall to 4 mA. If the input signal from the load cell(s) is greater than 4 mV/V (in a fault condition) then the output will also fall to zero. The fault condition is also signaled by the release of the FAULT output (normally closed, open collector) and by the red “ERROR” status LED.

Page 4 Manual LAC 74.1

Page 5

FLINTEC ...the right weigh

Typical Platform 600 x 600 mm

Off

0,5

1,0

%at 2mV/V SET ZERO Pot ccw = calib.

2,5

FLINTEC

LOAD CELLS 10Vdc 100mA

Exc

Inp Inp Sen

Sen

+++

Shield

+Excitation

+Sense

+Signal

-Signal

4,0

8,0

2,0

16,0

Exc

-Sense

-Excitation

Relative gain

Resolu.

1000 n

Pol. +/-

Fine adj.

SET SPAN Pot ccw = calib.

Analog 0/4 ... 20 mA or 0 ... 10 V

0,5

1,0

0,25

Out

20mA/ 10V

Gnd

I/V

ue Output

4,0

8,0

2,0

16,0

Fine adj.

CUT

SET

3,3

0,33

FILTER

160

500

0-20/4-20

20mA/10V

OUTPUT

Under

In range.

Over

CND

Error

Pwr. OK

LAC 74.1

Log Err.

Gnd

Logic Output

Open Collector,

normally closed,

opens at LAC error

PWR

12-24Vdc

GND

+12-24 V DC

Manual LAC 74.1 Page 5