Fisher DPR900 User Manual page 62

54.3
54.4
Discrete Inputs (DI)
Use FCODE 125 thru 128 to assign discrete input functions to Dll
thru Dl4. The controller recognizes a discrete input signal as active
when voltage is present at the input.
Function FCODE Option No Default Selected
Vallle Vallle
DII 125 Voltage present at input 1 1
NO voltage present at input 2
Dl2 126
Voltage present at input
1
1
No voltage present at input 2
D13 127 Voltage present at input 1 1
No voltage present at input 2
D14 128
Voltage present at input 1 1
No voltage present at input 2
External Discrete Signal Switching (A/M and
R/L) and Signal Tracking
Discrete signals DII and D12 are used to switch modes from auto to
manual and/or from remote to local. While the discrete input allows
changing of states, the initial state must have been enabled from the
front panel (i.e. to go from local to remote, the R button must initially
be set from the front panel). The discrete cannot be used to switch the
controller to the remote mode initially. Mode switching is on the trailing
edge of the discrete signal. Only the M button lights when the
controller is switched remotely. The yellow increase/decrease buttons
do not light, and do not function unless the M button has been
pressed. This activates the local/manual control state.
Setpoint tracking via FCODE 140 does not occur when remote
switching selects the manual mode. This prevents the accidental reset
of the setpoint in cases such as cascade control.
This function also controls the activation of output tracking if it has
been selected
as
active in the manual mode. To control the signal
manually, even after remote switching to manual, the user must press
the M button to activate the yellow increase/decrease buttons.
The controller cannot be switched into the auto mode as long as the
discrete signal remains active. DO1 (Auto/Manual status) is activated
when the controller is in manual mode and remains active until the
controller is in auto mode.
lJM6.1:DPR9Q0:9102 Change 1 -September 1991