D
4.2.12 Option B - Internal RH% Sensor Calibration
Not relevant to the D
4.2.13 Option C - Set Alarm Relay(S)
This option will only be available for models which have relay outputs fitted at the time of
ordering. Up to 4 relays can be fitted to each D. These are changeover relays,
single pole with all 3 contacts, off, common and on, (contacts 1, 2 and 3 - see chapter 4 for pin
connections) available to the user.
Each relay may be assigned to any software channel of the D, more than one
relay can be assigned to a single channel to give a ‘window’ threshold if required.
Option C will first ask the user to specify which relay to set, and then which software channel
to use as a threshold. The relay threshold must then be entered using the same format as
the full scale for that channel - an example is given on screen.
Leading zeros are required and the format must be adhered to. Invalid characters will restart
this sequence. Note that sometimes there may be internal rounding of figures due to multiple
linearisation tables and the set positions may deviate from the input values by one least
significant bit.
Your choices and threshold value is repeated on screen for your confirmation.
NOTE - for humidity, no sign (+ or -) is needed, only one decimal place is required, format is
xxx.x (e.g. 099.9). For thermistor channels the format is xxx.xx plus a + or - sign (e.g. +100.00).
All other channels must be entered as raw data, e.g. +19000 - however, these are
redisplayed for confirmation as scaled values if the channel being configured is set up as
AX+B. (See Appendix 5 for a table of wind direction degrees against raw data count for the
Vector W200P windvane.)
The relays will switch whenever the channel to which they are assigned is sampled i.e. at
each sample time.
e.g. if the sample code is set to 30 seconds (code 06) then it will compare the threshold value
with the channels reading every 30 seconds and switch accordingly.
When the logger’s other functions are used, e.g. offload in Main Menu mode, the relays will
remain in their last set position. They will hold this position until the logger reverts to its normal
‘sleep / sample / store’ mode. As soon as the Main Menu mode is left and the first sample
occurs, the relay assigned to the sampled channel will take on its new position, if its threshold
or the reading from the channel have altered.
To disable switching a relay, assign to an unused channel or set the threshold to a value
outside the normal operating range, above or below, depending on the desires contact
position.
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