Configuration software
4.5.7 Unit Details
4.5.7.1 Overview
The unit details options allow you to fine tune the operation of the WL-TX-900.
The WL-TX-900 only turns on the analog circuits and the +24V analog loop power
supply when they are actually required. You can reduce the module power
consumption by limiting the amount of time the analog circuitry and the +24V analog
loop supply is enabled.
Sample period - determines how often the module checks an analog signal. Warmup
time determines how long the analog circuits are powered up before performing the
sample. The analogue circuitry is powered all the time if the warmup period for any
analog input is set to a value longer than the sampling period. By setting the sample
time as long as possible, and setting the warmup time as short as necessary to power
the external conditioning circuitry, the module power consumption can be reduced.
Debounce time - the amount of time an input needs to have differed from its previous
value before it is recognised as having changed. This helps with noisy signals. Inputs
subject to a high level of noise can cause the module to transmit multiple messages
due to random changes to the input level. By setting the debounce time to a larger
value, the signal needs to change by the configured sensitivity for some time before a
change is registered and a new message is sent.
4.5.7.2 Unit Detail Options
Feature
Description
Thermocouple
debounce
For analog signals (e.g. thermocouple, analog 4-20 mA, and
module temperature), debounce time is the product of the number
of samples and the sample period. The signal must differ from the
previous value by the sensitivity value for this duration to register a
‘change of state’.
This means that changing the analog sample time will also change
the debounce time. For analog signals, a value of 0 or 1 generates
the quickest response and 255 the slowest response.
Thermocouple
sample period
This sets the period between samples of the thermocouple input.
A smaller value will cause mappings using this input to be
triggered more frequently (i.e. quicker response).
A larger value will cause mappings using this input to be triggered
less frequently (i.e. less power consumption).
Thermocouple
warm up time
The amount of time the analog circuits are turned on before
sampling the thermocouple input.
For normal thermocouples, these can be set to the minimum value
(i.e. 0.08 seconds).
If using an external (millivolt) device powered from the +24V
supply that requires a longer period to settle, you may need to set
this value to allow the external device to settle.
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