Eclipse UDC2500 Limit - Operating Your Limit Controller

Operating the Limit Controller
8/05 UDC2500 Universal Digital Limit ControllerProduct Manual 51
4.6 Operating Your Limit Controller
Operating Principles
The Limit Controller accepts signals from such sources as Thermocouples (T/Cs),
Resistance Temperature Detectors (RTDs), and Radiamatics. The equivalent PV signal is
compared with the Limit set point. If above (Hi Limit) or below (Lo Limit), a limit output
relay is de-energized. When de-energized, the output relay locks out and remains in this
state until the PV input signal drops below the high limit setpoint or rises above the low
limit setpoint, and the controller is reset manually from the front of the controller or
through an optional external switch.
Check the configuration
Make sure the Limit Controller has been configured to handle your process needs. Refer
to
Section 3 - Configuration for prompts and parameters.
• Input Parameters
• Alarm Set Points and type
• Limit Control Type - high or low
• External Reset (Contact Input) - enable or disable
• Power-up Logic - Reset (relay on) or Normal (same as before power down)
• Lockout selection
Power Up Logic
Configurable power-up logic lets you select the latching output relay to require “RESET”
or to provide normal operation at power-up. If power to the limit controller fails and
power is reapplied, the controller goes through power up tests then starts in one of the
following configurable conditions:
• If you configured RST at setup group “LIMIT”, the lower display will blink
“LIMIT” at power up. This will require reset via the
M-A RESET key or external
switch to obtain normal operation.
• If you configured NORM at setup group “LIMIT”, the display and limit controller
will function normally at power up, (that is, no reset of the latching relay is
required unless a limit has been exceeded). If the limit was latched when power
went down, the unit will be in limit at power-up.
Refer to
Section 3 - Configuration, subsection 3.4 Limit Parameters Set Up Group under
SET UP prompt “LIMIT” and make your selection at FUNCTION prompt “POWRUP.”