Limits view parameters
The
Limits
view includes these parameters:Parameter | Description |
|---|---|
High Clamp | Highest value that an output channel is allowed to reach in the control process. |
Low Clamp | Lowest value that an output channel is allowed to reach in the control process. |
Disable All Alarms | Indicates that all alarms are disabled for a channel. When the checkbox is selected, Latch Limit Alarms and Latch Rate Alarm are not available. The High Clamp and Low Clamp limits are still effective though, so the output signal is constrained to within the clamp limits. |
Latch Limit Alarms | Indicates that the high and low limit alarms are retained even after the condition ceases. The high or low limit alarm is set if the requested output level is beyond the clamp limit (>High or <Low). This is useful if you want to detect a transient alarm condition and preserve its indication until the alarm is explicitly unlatched. To unlatch alarms, select Unlatch or send a CIP message using the MSG instruction. |
Ramp in Run Mode | Indicates that ramping is enabled during Run mode. Ramping occurs between the current output level and any new output value received. If Ramping is enabled, the output is allowed only to change at the configured ramp rate limit. |
Ramp Rate | Indicates the maximum rate of change an output makes in engineering units/second. Ramp Rate also serves as a trigger point for a ramp rate limit alarm when Ramp in Run Mode is selected.Ramp Rate is also used for ramping to a user-defined value in Program or Fault mode.If any of the three ramp functions are enabled, enter a Ramp Rate that is more than 0. If none of the three ramp functions are enabled, enter a Ramp Rate of 0. Ramp functions include:
If the commanded output value (O.ChXData) changes faster than the specified Ramp Rate , a ramp rate limit alarm is signaled (I.ChXRampAlarm) and the rate of change in actual analog output value is reduced to the configured Ramp Rate . |
Latch Rate Alarm | Indicates that the rate alarm is retained even after the condition ceases. The ramp rate alarm is set if there is a minimum change of input between samples of a channel. The Max Ramp Rate should be greater than zero when this checkbox is selected. This is useful to detect a transient alarm condition and preserve its indication until the alarm is explicitly unlatched. To unlatch alarms, select Unlatch or send a CIP message using the MSG instruction. |
Unlatch | Unlatches the adjacent alarm. Not available when offline or Disable All Alarms is selected. |
Unlatch All | Unlatches all alarms for the channel. Not available when offline or Latch Limit or Latch Rate alarms are not selected. |
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