Setpoint Ramp And Hold - Fisher DPR900 User Manual

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Configuration
5-33
5.7.8
Setpoint Ramp and Hold
May 1991
Changing the SP limits also changes the O-100
percent scales used by the SP and PV bargraphs
to that of the setpoint limits: 0 percent = lower limit
and 100 percent = upper limit.
When setpoint limiting is used, and the user elects
to retransmit the SP signal out on A02, the
transmitted signal will be the resealed O-l 00%
signal.
Setpoint ramping may be required for slow starting systems, such as
a steam system that requires warming up. The user selects initial
setpoint ramping options via FCODE 109. The controller may ramp
either the remote or the local setpoint value and can be configured to
indicate Ramp Status with DO3 and D04.
Function FCODE
Option No Default Selected
VZllW V&e
Setpoint
109 Disabled 0 0
Ramping
Enabled,
output on
DO>DO4 1
Enabled, no indicated
output
2
When ramping is configured, the ramp speed and ramping time period
must be set via FCODE 13 and 14.
Function Paramefers
Setpoint Ramping rate
Ramping Ramping timer
FCODE Range Unit Increment Default Selected
Vak V&.K3
13 Mt?k?S. Min. 1 digit Max
14
O-999
Min. 1 digit 1 Min
The controller determines the ramp direction (up or down) depending
on whether the setpoint value lies above or below the current process
value. The ramp starts when the controller is switched from manual to
auto. This switching can be manual or done via the control signal at
Dll or Dl2.
The following shows an example of the controller ramping function.
UM6.1 :DPf?900:9102