1.2 Front Panel Operation
1 – 5
1.2.2
Ramping
The ramping feature of the SIM960 PID Controller allows the user to
linearly slew the internally generated setpoint level from its current
value to a new value. The slew rate may be changed using the
SP Ramp
parameter on the front panel.
The indicator to the right of
SP Ramp
shows whether ramp-
ing is enabled or disabled.
Use [On
/
O
ff
] (with
SP Ramp
se-
lected) to enable
/
disable ramping.
When disabled, changes to
the
Internal Setpoint
parameter take e
ff
ect immediately.
When
ramping is enabled, however, changes to
Internal Setpoint
do not
immediately take e
ff
ect. Instead,
Internal
(in the Setpoint block of
the INPUTS section of the front panel) begins to blink, showing that
a new setpoint has been entered and a ramp event is now pending.
To begin the ramp, press [Ramp Start
/
Stop]. Now, the
Internal
blink
rate doubles, indicating that the setpoint is ramping. To pause the
ramp, press [Ramp Start
/
Stop] ˙
When the ramp is paused, the
In-
ternal
blink rate becomes uneven. To continue the ramp, press
[Ramp Start
/
Stop] again. When the setpoint reaches the new pro-
grammed value, the ramp automatically terminates, and
Internal
stops blinking.
Note,
SP Ramp
has no sign in the numerical display. This is be-
cause the polarity of the ramp rate is unambiguously determined
by whether the newly entered setpoint is greater or less than the
current setpoint. The range of available ramp rates is from 1 mV
/
s
to 10,000 V
/
s. For ramp rates less than or equal to 1 V
/
s, the rate
is dynamically trimmed based on real-time measurements from the
onboard A-to-D converter.
1.2.3
Connections
Connect the sensor output of the system to be controlled to the “Mea-
sure” input of the SIM960˙If an external setpoint is to be supplied, con-
nect this to the “Setpoint” input, and use the button in the INPUTS
section of the front panel to select “External” input. Before connect-
ing the SIM960 output to the system to control, it may be necessary to
set the user programmable output upper and lower
Limits
to guard
against damaging the system. Care should be taken to insure that
the programmed output range is consistent with the system input
range. Once the limits have been programmed, connect the SIM960
output to the system input.
SIM960 Analog PID Controller
