Input Range

The Input Gain parameter sets the amplification range for the input signal.

The Offset parameter is generally used to compensate for the deadload; particularly in cases where the combined weight of deadload and payload exceed the A to D converter input range.

Input Range and Offset are considered part of the loadcell's calibration. To burn these values into the module's EEPROM memory and protect them in the event of a power outage, use the Save Calibration command.

Set Gain/Offset, Command #8461

Set Gain limits the input range. The gain is applied to the signal after offset compensation.

Setting the Gain to 0 limits the input range to ±20mV (Default setting), setting it to 1 limits the input range to ±80mV.

Set Offset sets the offset compensation, which is applied to the input signal before the gain. By default, the offset is set to 0mV (no offset).

Possible values are in the range of ±31, where: 1LSB ≈ 0.5mV/V (= 2.5mV at exactly 5V excitation). Hence, the maximum offset compensation is ±15.5mV/V (= ±77.5mV at exactly 5V excitation).

To calculate the offset value, measure the differential voltage at the input, between the -SG and +SG terminals, and then calculate the offset value according to 1LSB ≈ 0.5mV/V.

If, for example, the differential voltage at the input is 10mV, use -4 as the offset value.

Notes ♦	Changing Gain or Offset requires you to recalibrate and save all calibrated points.
♦	If the application requires you to set Input Range/Gain, you must make these settings before you calibrate points. Setting the Input Range/Gain after calibrating points invalidates the calibrated points.
♦	Offset values out of the ±31 range will be truncated and no error will be returned.
♦	The uV/V rep. mode uses its own input range settings and therefore is not affected by the command.

Command parameters

SI 141

Determines the number and location of the Loadcell.

Set Gain

LC #	DIN Location
0-2	Always 0	0-7

Storing the value 202 into SI 141 sets the gain for Loadcell 3 on the 3rd module on the DIN rail.

Set Offset

Offset	LC #	DIN Location
1	0-2	Always 0	0-7

Storing the value 1202 into SI 141 sets the Offset for Loadcell 3 on the 3rd module on the DIN rail.

SI 142

MI address; this MI will contain the Command Status indication

SI 143

SI 144 provides either the Gain/Offset value, or the location of the MI containing the value.

If the value of SI 143 is:	Result
4	The Gain/Offset value will be taken directly from SI 144.
10	The value in SI 144 provides the address of an MI that provides the Gain/Offset value.

SI 140

Command number: 8461

Read Gain/Offset, Command #8717

Reads the input range Gain/Offset from the Loadcell to the PLC.

Command parameters

SI 141

Determines the number and location of the Loadcell.

Read Gain

LC #	DIN Location
0-2	Always 0	0-7

Storing the value 202 into SI 141 reads the gain for Loadcell 3 on the 3rd module on the DIN rail .

Read Offset

Offset	LC #	DIN Location
1	0-2	Always 0	0-7

Storing the value 1202 into SI 141 reads the Offset for Loadcell 3 on the 3rd module on the DIN rail.

SI 142

MI address; this MI will contain the Command Status indication

SI 146

If the value of SI 146 is:	Result
10	When the command runs, the value in SI 147 provides the address of an MI that will contain the Gain/Offset value.

SI 140

Command number: 8717

Input Range

Set Gain/Offset, Command #8461

Read Gain/Offset, Command #8717

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