SRS Labs CTC100, Руководство пользователя

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Remote Programming 106
CTC100 Programmable Temperature Controller
By default, each PID loop has no assigned input channel. In this state, all PID settings are locked
except for
channel.PID.input
. If a macro attempts to change the setpoint, the feedback gains,
produced and the macro continues to run. An error message is only
printed if Verbose is set to High.
Channel. PID.D 0.0
Channel. PID.I 0.0
Channel. PID.P 0.0
These instructions set the PID gain factors. The PID equation is:
Output
t
= Pe
t
+ 0.5IT( (e
0
+ e
1
) + (e
1
+ e
2 t 2
+ e
t 1
) + (e
t 1
+ e
t
) ) + (D/T)(e
t
e
t 1
)
where P, I, and D are the derivative gains, e
t
is the error (the difference between the setpoint and
the PID input signal) at time t, and T is the ADC sampling time. Thus, larger values of P, I, or D
produce a faster feedback response. Increasing P or I tends to create oscillations, while increasing
D reduces oscillations but adds noise. Negative values of P, I, and D should be used if the output
drives a fan or other device that cools the sample.
Errors: Attempting to set P, I, or D when no PID input channel is selected produces a run-time
produces a run- . Attempting to set P when the PID mode is set to
Follow produces an assembly-
Channel. PID.Ffwd " Channel name "
Selects a feedforward input channel. If a valid channel is selected and the PID mode is set to
lue the value of the feedforward channel is added to the PID output at each ADC
conversion. To disable this feature, issue the
channel. ffwd()
instruction with an empty
argument.
This feature can be used to implement feedforward control. The feedforward input should be
some quantity with a known and predictable effect on the feedback system. The feedforward
gain controls can be used to scale the feedforward effect.
Channel. PID.Gain 0.0
Channel. PID.ZeroPt 0.0
These instructions set the offset and gain for Follow mode. They are only available when the
PID mode of
Channel
is set to Follow. In Follow mode, the value of an output channel follows
the value of another channel with offset and gain applied:
Output = ( Input Zero pt ) × Gain
when the input is
equal to the zero point, the output is zero.
Errors: Issuing a zero point or gain instruction when the PID mode is set to On or Off produces
an assembly-tim
Channel. PID.Input " Channel name "
Determines which temperature the PID feedback loop controls. If the channel name does not
exist, any previously-selected input is deselected, leaving no PID input selected and the PID
feedback disabled.
Channel. PID.Mode { Off, On, Follow }
Enables or disables PID feedback. Turning feedback off freezes the output at its current value
current PID gain of the channel
selected with the input instruction, adjusted by the Zero pt and Gain factors.