Watlow CPC400 - Manual (Page 23)

CPC400 Series User’s Guide Chapter 1: System Overview
Doc. 0600-2900-2000 Watlow Anafaze 9
Safety
Watlow Anafaze has made every effort to ensure the reli-
ability and safety of this product. In addition, we have pro-
vided recommendations that will allow you to safely install
and maintain this controller.
External Safety Devices
The CPC400 controller may fail full-on (100 percent output
power) or full-off (0 percent output power), or may remain
full-on if an undetected sensor failure occurs.
Design your system to be safe even if the controller sends a
0 percent or 100 percent output power signal at any time.
Install independent, external safety devices such as the
Watlow Anafaze TLM-8 that will shut down the system if a
failure occurs.
Typically, a shutdown device consists of an agency-ap-
proved high/low process limit controller that operates a
shutdown device such as an mechanical contactor. The lim-
it controller monitors for a hazardous condition such as an
under-temperature or over-temperature fault. If a hazard-
ous condition is detected, the limit controller sends a signal
to open the contactor.
The safety shutdown device (limit controller and contactor)
must be independent from the process control equipment.
WARNING! The controller may fail in a 0 percent or 100 per-
cent output power state. To prevent death, per-
sonal injury, equipment damage or property
damage, install external safety shutdown devices
that operate independently from the process con-
trol equipment.
With proper approval and installation, thermal fuses may
be used in some processes.