Page 27 801P5 Smart Switch
TM
NOTE
NOTE
4-20 MILLIAMPERE OUTPUT SCALING
The 4-20 mA output is scaleable, allowing 4 mA to represent any
pressure between 0% and 66% F.S.O., and 20 mA to represent
any pressure between 33% and 100%F.S.O. This feature is helpful
in systems where the normal operating pressure falls within the
pressure range of the unit. For example, let’s assume that the
Smart-Switch
TM
has a pressure range of 0 to 100 PSIG, and the
process that it is monitoring operates between 20 and 80 PSIG.
The equipment that is monitoring the 4-20 mA output expects 4
mA to represent 20 PSIG, and 20 mA to represent 80 PSIG. Using
the following instructions, by setting SCLO to 20 PSIG and SCHI
to 80 PSIG, these conditions will be met.
Scale Low (SCLO)
To set the pressure at which the output equals 4 mA, press the
[UP/DOWN ARROW] keys until SCLO is displayed. Press
[SELECT] to enter the submenu. Use the [SELECT] key to move
from digit to digit and use the [UP/DOWN ARROW] keys to
adjust each digit. Once you have set the pressure, press [STORE]
to save your setting. The range of adjustment for this function is
zero psig to 66% of F.S.O.
The difference between the SCLO setting and the SCHI setting
must be at least 33% of F.S.O.
Scale High (SCHI)
To adjust the pressure, at which the output equals 20 mA, use the
[UP/DOWN ARROW] keys until SCHI is displayed. Use the
[SELECT] key to enter the submenu. Use the [SELECT] key to
move from digit to digit and use the [UP/DOWN ARROW] keys
to adjust each digit. Once you have set the pressure that should
equal 20 mA output, press the [STORE] key to save your setting.
The range of adjustment for this function is 33% F.S.O to 100%
of F.S.O.
The difference between the SCLO setting and the SCHI setting
must be at least 33% of F.S.O.