Limit Delay

Temprecord Mk III has a the ability to compare the logged temperatures and humidity against upper and lower limits, and report whether the limits have been exceeded via the red and green LED on the logger. In some situations, the logger must be started while the temperature/humidity is outside the limits and it is undesirable for this situation to be reported as a temperature/humidity outside of the limits. Also, there are applications where a brief excursion outside the limits may be expected, and is not to be reported as an out-of-range error.

To accommodate these situations, Temprecord allows you to set a limit delay parameter. The limit delay is used in two ways - it affects the behaviour of both the safe range, and also the lower and upper temperature and humidity limits.

•The limit indicators (upper temperature exceeded, lower temperature exceeded, upper humidity exceeded, lower humidity exceeded) are only set when the number of continuous samples exceeding the respective limit is greater then the limit delay parameter. In other words, the limit delay specifies how many consecutive samples are tolerated outside the limits before an out-of-limits condition is flagged.

To have the limit indicators set (and therefore the red LED flash) as soon as any single sample exceeds the respective limit, set the limit delay to 0.

•If the enable safe range option is checked, comparison of the temperature (and/or humidity) values starts as soon as the number of samples taken inside the safe range exceeds the value specified in the limit delay parameter. In other words, the limit delay specifies how many consecutive samples are tolerated inside the limits before checking of the samples against the limits begins. For example, if the limit delay is set to 5, the checking of temperatures and/or humidity against limits will not start until more than five successive samples have been recorded as inside the safe range.

To have comparison against the limits begin as soon as a sample is inside the safe range, set the limit delay to 0.

On the LCD logger the behaviour of the LED's when limits are transgressed is configurable - i.e. when you program a logger you can determine whether the LED's indicate the state of the limits. See Enable Status LEDs for more information.

In the Mk3 Temprecord loggers, the value of the delay (in samples) also sets the safe range delay, i.e. setting the limit delay in the Mk3 logger also sets the safe range entry delay, and the limit delay in turn is shared between the temperature and humidity channels, whereas in the G4 (LCD) logger these parameters are separate and can also be independently programmed for each humidity or temperature channel.