Instruction Manual

Instruction Manual
D103434X012
Blocks
November 2014
117
input connector. In RemoteCascade (RCas) mode, the SP [8] comes from a host computer that writes to RCAS_IN [28].
The range and units of the SP [8] are defined by the PV_SCALE [11] attribute.
In Manual (Man) mode the SP [8] automatically tracks the PV [7] value when you select the SP‐PV Track in Man I/O
option in IO_OPTS [14]. You can disable this option in OOS mode only.
The SP [8] value is limited to the range defined by the setpoint high limit attribute (SP_HI_LIM [20]) and the setpoint
low limit attribute (SP_LO_LIM [21]).
In Auto mode, the rate at which a change in the SP [8] is passed to OUT [9] is limited by the values of the setpoint
upward rate limit attribute (SP_RATE_UP [19]) and the setpoint downward rate limit attribute (SP_RATE_DN [18]). A
limit of zero disables rate limiting.
As shown in figure B‐12, the block executes a percentage of the set point change each macrocycle. For example, if the
set point rate is set at 10% per second and the macrocycle is 500 milliseconds (0.5 seconds or 50% of 1 second), then
during the first macrocycle the set point will change 5% (50% of the 10% per second rate). If the macrocycle is 750
milliseconds (0.75 seconds or 75% of 1 second), then during the first macrocycle the setpoint will change 7.5% (75% of
10).
In Auto mode, the converted SP [8] value is stored in the OUT [9] attribute. In Man mode, the OUT [9] attribute is set
manually, and is used to set the analog output defined by the CHANNEL [22] parameter.
Figure B‐12. Analog Output Function Block Timing Diagram
B2718‐1
CAS_IN, 2
OUT
SP
Time
SP RATE UP
SP
RATE DN
1 second 1 second 1 second 1 second
1 macrocycle
1 macrocycle
TRANSDUCER BLOCK
TRAVEL TARGET
Action On Fault Detection
To define the action you wish the compensated value to take when the block is in CAS mode, and the CAS_IN [17]
input detects a communication failure, or is commanded to go to fault state by the upstream block or the resource
block, configure the following parameters:
IO_OPTS [14]: Determines the action OUT [9] will take upon a fault state. If the IO_OPTS [14] “Fault State to Value” is
not selected, then OUT [9] holds its last position when Fault State is set. If “Fault State to Value” is selected, OUT [9]
goes to the FSTATE_VAL [24] value when Fault State is set.