Humidity Control Operation; Gp Timer Set-Up; Trim Heater Control Via Mercury Case Controller Range - Resource Data Management Mercury PR0018 User Manual

Mercury Switch User Guide

Humidity Control Operation

To utilise this feature a Humidity/Temperature Display is required (PR0445). Connect the Humidity/Temperature display to the display
port on the Mercury Switch. The control algorithm will use the humidity reading from the display in calculating the percentage at which the
trim relays are to be pulsed.
When the measured rH is below the "Humidity Low" parameter the Mercury Switch will pulse the Mercury case controller trim relays to
the duration set by the "Trim Low" parameter. When the measured rH is above the "Humidity Low" parameter but below the "Humidity
High" parameter the Mercury Switch will pulse the Mercury case controller trim relays in proportion to the line drawn between the low and
high levels. When rH goes above the "Humidity High" level the Mercury Switch will pulse the Mercury case controller trim relays at the
"Trim High" setting. Setting the trim high parameter to 70% will result in 30 % energy savings as the controller trim relays will never pulse
on for more than 70%. The trims are pulsed over a 5 minute period. Therefore if the Mercury Switch calculates the trim percentage as
50% then the trim relay will be on for 2 and a half minutes and then off for 2 and a half minutes.

GP Timer Set-up

It is possible to set the Mercury Switch humidity control to operate at specific times. For this operation to occur set the parameter "Trim
Mode" to "Remote". A GP Timer channel must be set up to control the timer on/off periods of the Mercury Switch. For GP Timer set up
please refer to the Data Manager user guide found on the RDM website. The following settings should be followed in the GP setup.
Output Type
Output Mask
Output Channel
When the parameter "Trim Mode" is set to "Remote" and the Data Manager GP timer channel directed to the Mercury Switch is in the on
period the humidity control will operate as described above. During the Data Manager GP timer channel off period the relay will pulse to
the preset "Trim Off Level" parameter. For example if the trim off level is zero then the trims will be completely off. Thus allowing the user
to save energy when the store isn't trading and the trims are not required.
Note if you wish the Mercury controller trim relay to follow the Data Manager Trim Control feature and not the Mercury Switch settings
then please see the Mercury Controller user document (Parameter P-12).

Trim Heater Control via Mercury Case Controller Range

Energy savings via the Mercury controller range can be achieved in a number of ways. One of which is pulsing the trim heater relay off
for a given period of time. One way to pulse the trim heater relay in the Mercury case controller range is by setting the parameter "Trim
Level". This sets a percentage level, of a 5-minute period, to pulse the trim heater relay off/on. Using this parameter pulses the trim relay
irrespective of the actual shop floor humidity. For greater energy savings the Data Manager energy feature trim control or the Mercury
Switch trim control feature can be used. These two options pulse the trim relay dependant on the actual shop floor humidity levels. Thus
if the shop floor humidity is relatively low the trim heaters can be pulsed off for longer durations. Please see the relevant user guides for
further details.
RDM recommend that the trim heater pulse module is used in all instances (PR0723). This module is fitted in between the trim heater of
the case and the relay output of the Mercury Controller which is pulsing the heater. The trim heater module output provides a smoother
power distribution, compared to using the relay output direct, as it switches at the zero voltage crossover point. Switching the trim heater
on and off via a normal relay, without using the RDM trim heater pulse module, may damage the trim heater and reduce the operational
life of the heater. Therefore RDM recommend the use of this module in every trim heater control application.
Warning
Ensure that all power is
switched off before
installing or maintaining
this product
Humidity
High
Humidity
Low
– This should be set to "General".
– This should match the "Controller Name" e.g. "45a"
– Set to "13". This will allow the GP Timer to control the state of the timer.
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