Sensor LDU 68 Series Manual Download Page 30

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Ideas in Measuring ..

TECHNIQUES LIMITED

Page 30

LDU 68 Series Manual

Issue 1h

Please note that when the Logic Output is ON it is conducting.

An example of a negative hysteresis of 100 kg (H0= -100) on a setpoint (S0) of 2000 kg (see lines
1 & 2 of the table above):

When the weight is increasing between 0 kg and 2100 kg the logic output is “ON”. Once the weight
increases above 2100 kg, the logic output is “OFF”. The logic output will come “ON” again when
the weight drops below 2000 kg.

An example of a positive hysteresis of 100 kg (H0= +100) on a setpoint (S0) of 2000 kg (see lines
3 & 4 of the table above):

When the weight is increasing between 0 kg and 1999 kg the logic output is “OFF”. Once the
weight increases above 1999 kg, the logic output is “ON”. The logic output will switch “OFF” again
when the weight value drops below 1900 kg.

Example

Setpoint

Hysteresis

Logic Output State

Load

S0 = 2000 kg

Increasing

H0 = -100kg

H0 = 100kg

Above 2000 kg ON

0 . . . 2100 kg ON

Above 2101 kg OFF

Above 2001 kg OFF

Above 1901 kg ON

Below 2000 kg ON

0 . . . 1999 kg OFF

Below 1900 kg OFF

Decreasing

Request / Setting

5.10 Setpoint Commands - Sn, Hn, An

The LDU 68.x has 2 logic outputs where the status is dependent on the weight value (setpoint).
Each logic output can be assigned an independant setpoint value (Sn) with corresponding
hysteresis/switch action (Hn) and base (An - switch on the gross or the net weight)

Using the H0 command you can set the hysteresis on the setpoint value and define whether the
logic output switches on or off when the setpoint value is reached. The numeric value of H0 sets
the hysteresis and the polarity sets the action when the setpoint is reached.

Similarly, to read or change the setpoint value for logic 1, issue the commands as above but
substitute S1 instead of S0.

S0 Setpoint value for logic output 0

H0 Hysteresis and switch action for logic output 0

Master (PC / PLC) sends

LDU XX.X responds

Result

S0_03000

0+01500

Setpoint S0 set to 1500 d

Setpoint S0 changed to 3000 d

Request / Set base for logic output 0

Setpoint range between ± 1 (minimum) and ± 99999 (maximum)
Similarly, to read or change the hysteresis value for logic 1, issue the commands as above but
substitute H1 instead of H0.

The A0 command defines the base on which the setpoint acts. If A0 is set to “0” then the setpoint
acts on the unfiltered gross weight. So when the unfiltered gross weight reaches the setpoint, the
logic output turns on/off. Similarly, if A0 is set to “1” then the setpoint acts on the unfiltered net
weight.

Similarly, to read or change the base for the setpoint of logic 1, issue the commands as above but
substitute A1 instead of A0.

NOTE: All changes to the setpoint settings have to be stored in EEPROM using the SS command.
See section 5.11

A0 Request / Set the base for logic output 0

Request / Set Hysteresis value on logic output 0

Master (PC / PLC) sends

LDU XX.X responds

Result

H0_100

0-00100

Hysteresis on S0 set to -100 kg

Hysteresis on S0 changed to +100 kg

Master (PC / PLC) sends