
4.4 How to Use the Remote SP
E5AK
4--11
4.4 How to Use the Remote SP
·
Taking a remote SP input (4 to 20 mA) as the set point is referred to as
the “remote SP” function. The remote SP function is enabled only when
the “remote SP (RSP) enable” parameter (option mode) is set to “ON”.
·
Remote SP upper-and lower-limit values can be set by scaling.
·
Inputs within the range 4 to 20 mA (-10 to 110%) are allowed as remote
SP inputs. Inputs not within this range are regarded as out-of-range
input values. In this case, input is clamped at the remote SP lower or
upper limit values, and the “RSP” LED blinks.
·
If the output function “RSP input error” is assigned for when an out-of-
range remote SP is input, the “RSP input error” output is turned ON.
Control output also switches to the setting of the “MV at PV error”
parameter.
·
Set the upper limit value in the “remote SP upper limit” parameter and
the lower limit value in the “remote SP lower limit” parameter (option
mode).
RSP (%)
2.4 (-10%)
4
20
21.6 (-110%)
Input (mA)
Out-of-range input
(blinks of upper-and lower-limit values)
Upper limit value
Lower limit value
·
When the “Set point upper limit” or “Set point lower limit” parameters
are changed, the remote SP upper-and lower-limit values are forcibly
changed to the set poimt upper-and lower-limit values. The following
example shows how the remote SP upper-and lower-limit values are
changed when the set point upper limit value is changed from A to B.
Set point limiter
Upper-and lower-limit values of the limiter
Before change
Changed to
upper limit value
RSP scaling upper-and lower-limit values
Set point
Set point
Upper limit value
changed from A to B
B
A
RSP scaling range
·
The set point held internally by the E5AK controller is referred to as the
“local SP (LSP).”
·
If the multi-SP function is enabled, set points 0 to 3 are enabled for use
as the local SP.
·
Use the “SP mode” parameter to switch between the remote SP and local
SP. When the SP mode parameter is set to “
” (remote SP), the
“RSP” LED lights. When the SP mode parameter is set to “
”, the
controller is in the local SP mode.
J
Scaling
F
Relationship with
set point limiter
J
SP mode
LSP
RSP enable
RSP
SP mode