User`s manual

Watlow EZ-ZONE
®
ST • 81 • Appendix
Indication Description Possible Cause(s) Corrective Action
Process doesn’t con-
trol to set point
Process is unstable or never
reaches set point
• Controller not tuned correctly • Perform autotune or manually tune
system.
• Control mode is incorrectly set • Set control mode appropriately (Open
vs Closed Loop).
• Control set point is incorrect • Set control set point in appropriate
control mode and check source of set
point: remote, idle, profile, closed loop,
open loop.
Temperature runway Process value continues to
increase or decrease past set
point.
• Controller output incorrectly pro-
grammed
• Verify output function is correct (heat
or cool).
• Thermocouple reverse wired • Correct sensor wiring (red wire nega-
tive).
• Controller output wired incorrectly • Verify and correct wiring.
• Short in heater • Replace heater.
• Power controller connection to con-
troller defective
• Replace or repair power controller.
• Controller output defective • Replace or repair controller.
[`100] Device Error
[rEtn]
Controller displays internal
malfunction message at
power up.
• Controller defective • Replace or repair controller.
[`h;Er] Heater Error
Heater Error • Current through load is above current
trip set point
• Check that the load current is proper.
Correct cause of overcurrent and/or en-
sure current trip set point is correct.
• Current through load is below current
trip set point
• Check that the load current is proper.
Correct cause of undercurrent and/or
ensure current trip set point is correct.
[`C;Er]
Current Error
Load current incorrect. • Shorted solid-state or mechanical
relay
• Replace relay.
• Open solid-state or mechanical relay • Replace relay.
• Defective current transformer or con-
troller
• Replace or repair sensor or controller.
• Noisy electrical lines • Route wires appropriately, check for
loose connections, add line filters.
Menus inaccessible
Unable to access [`SEt],
[oPEr], [FCty] or [ProF]
menus or particular prompts
in Home Page
• Security set to incorrect level • Check lockout setting in Factory Page.
• Digital input set to lockout keypad • Change state of digital input.
• Custom parameters incorrect • Change custom parameters in Factory
Page.
EZ-Key doesn’t work EZ-Key does not activate re-
quired function
• EZ-Key function incorrect • Verify EZ-Key function in Setup
Menu.
• EZ-Key function instance not correct • Check that the function instance is
correct.
• Keypad malfunction • Replace or repair controller.
[``no] upper display
[`dEu] lower display
The RUI (Remote User Inter-
face) will not communicate
with the controller at the
selected zone.
• Communications wired incorrectly
• Communications wires routed with
power wires
• Zone address set out of range
• RUI or controller defective
• Check and correct wiring.
• Check and correct wiring.
• Check zone range and address.
• Replace or repair RUI or controller.
[uALU]
Value cannot be displayed • Scaling is out of range • Check scaling.
• Call technical support.