Watlow MLS - Manual (Page 84)

72 MLS User’s Guide
Setup
Input Reading Offset
Use this menu to make up for the input signal's inaccuracy. For
example, at temperatures below 400
º F, a type J thermocouple may be
inaccurate ("offset") by several degrees F. Use an independent
thermocouple or your own calibration equipment to find the offset for
your equipment. To correct for offset errors, change the factory default
setting to a positive or negative value for the loop you are editing. (A
positive value increases the reading and a negative value decreases it.)
Selectable range: -300 to +300.
NOTE
If the input type is Linear, Pulse, or Skip, you will not
see the Input Reading Offset menu.
Linear Scaling Menus
The linear scaling menus appear under the Setup Loop Inputs main
menu, and they are available for Linear and Pulse inputs only. It lets you
scale the "raw" input readings (readings in millivolts or hertz) to the
engineering units of the process variable.
You'll only see the linear scaling menus if you set the
loop's input type to Linear or Pulse.
For linear inputs, the input reading is in percent (-16.6 to 100%)
representing the -10-60 mV input range of the MLS. The scaling
function is defined by two points on a conversion line. It relates the high
PV to the high reading and the low PV to the low reading to define the
line. The engineering units of the process variable can be any arbitrary
units.
LOOP PROCESS UNITS
ALARM SETPOINT STATUS OUT%
06 INPUT READING
OFFSET? 0
º F