Watlow CLS200, MLS300 and CAS200 - Manual (Page 59)

Chapter 3: Controller Parameter Descriptions
Communications Specification 53
NOTE
Use the High Process Variable and Low Process Variable
for an offset on all types of inputs. Add or Subtract the off-
set from both the High and Low Process Variables full scale
valves. For example, for a J-type thermcouple, the full
range is 14000 (1400°F) to –3500 (–350°F) with an offset of
+5 degrees set the high Process Variable to 14050 and the
low Process Variable to –3450, moving the full range scale
up 5 degrees.
Precision (19)
The precision determines the number of decimal places in the associated
parameters.
The value stored in this parameter affects several other parameters.
• Range: –1 to +4.
• Default: –1 for a J-type thermocouple.
The MLS, CLS and CAS do not store any floating-point values. Instead,
they use the Precision parameter to simulate floating-point calculations
for these other parameters:
• Process variable
• Setpoint
• Proportional band
• High process alarm
• Low process alarm
• Deviation band alarm
• Heat/cool spread
• Alarm deadband
• Ready setpoint
• Segment setpoint
• Tolerance value
When the controller sends values for these parameters to host software,
it sends them as integers. To convert the numbers to a decimal, the host
software must do the following:
(1) Take the number from the controller.
(2) Divide it by 10 |p| (where |p| is the absolute value of the precision set-
ting. So for example, if the precision is set to –1, divide values read
via communications by 10, and if the precision is 2, divide by 100).