tekmar 664 Snow Detector & Melting Control Installation - Manual (Page 20)

20 of 36 © 2009 D 664 - 07/09
4–20 mA Device
The 4–20 mA output terminals (1 and 2) can not be tested without power applied to the control. Since no power is supplied to
the control at this point, the 4–20 mA output cannot be tested. Please refer to the operation test below.
2 3
Opn/
Var
xxx
+
xxx
–
4
Pwr
Mix
5
Cls
1
4 - 20 mA
2 1
4-20 mA
Test the 4-20 mA output
using a milliamp meter
1000 ma = 1 amp
- +
6.4 mA
Milli Amp
The control’s exterior can be cleaned using a damp cloth. Moisten cloth with water and wring out prior to wiping control. Do no use
solvents or cleaning solutions.
DIP Switch Settings
The DIP switch settings on the control are very important and should be set to the appropriate
settings prior to making an adjustments to the control through the User Interface. The DIP
switch settings change the items that are available to be viewed and / or adjusted in the User
Interface.
If a DIP switch is changed while the control is powered up, the control responds to the change
in setting by returning the display to the VIEW menu. This is true for all the DIP switches except
for the Lock / Unlock DIP switch.
Idle Demand
Melt Demand
Connecting The Control
Make sure all power to the devices and terminal blocks is off, and
remove any remaining jumpers from the terminals. Reconnect the
terminal blocks to the control by carefully aligning them with their
respective headers on the control, and then pushing the terminal blocks
into the headers. The terminal blocks should snap fi rmly into place.
Install the supplied safety dividers between the unpowered sensor
inputs and the powered wiring chambers. Apply power to the control.
The operation of the control on power up is described in the Sequence
of Operation section of the brochure.
Test the 4-20 mA Output
If a 4-20 mA device is used, connect an ammeter to the 4-20 mA output
terminals (1 and 2) and observe the current reading during operation.
When the 4-20 mA modulation increases, the initial percentage output
is zero and the meter should read 4 mA. As the % Output increases, the
meter reading should increase until 100% Output is reached at which
point the meter should read 20 mA. When the 4-20 mA modulation
decreases, the meter should start at 20 mA and eventually reach 4 mA
when the display shows 0% Output.
Note: The 4-20 mA output can only be tested if 4-20 is selected in the
Mixing item of the ADJUST menu.
Cleaning
LOCK / UNLOCK (FACTORY SETTING IS UNLOCK)
The Lock / Unlock DIP switch is used to lock and unlock the access level of the control and tekmar Net™ tN2 device. Once locked,
access levels can not be changed. To determine if the control is currently locked or unlocked, a small segment representing a padlock
is viewed in the bottom right hand corner of the display. When the padlock is closed, the access level cannot be changed.
To change the access level, set the DIP switch to the unlocked, or down position. The current access level of the control or
tekmar Net™ tN2 device is viewed in its Miscellaneous (Misc) menu. While viewing the access level, use the
▲
and
▼
keys to select
between the Limited (LTD), User (USER), Installer (INST) or Advanced (ADV) access levels.
To lock the access level, select the appropriate access level in the Miscellaneous (Misc) and move the DIP switch from the unlocked
position to the locked position. As long as the DIP switch is in the locked position, the access level of the control or tekmar Net™ tN2
device can no longer be viewed or adjusted in its Miscellaneous (Misc) menu.
IDLE DEMAND / MELT DEMAND (FACTORY SETTING IS MELT DEMAND)
The Idle Demand / Melt Demand DIP switch is used for melting and idling operation. The position of the DIP switch determines what
the Melt / Idle Demand terminals (19 and 20) are used for. When the DIP switch is set to the Melt Demand position, the Melt / Idle
Demand terminals (19 and 20) are used to place the snow melting system into Melting mode. When the DIP switch is set to the Idle
Demand position, the Melt / Idle Demand terminals (19 and 20) are used to force the snow melting system into Idling mode.