Thermcraft XST-3-0-36-3V - Manual (Page 255)

Installation and Operation Handbook Load Current Monitoring and Diagnostics
2416 Controller 8-1
8 Chapter 8 LOAD CURRENT MONITORING AND
DIAGNOSTICS
Current flowing in a system of electrical heating elements (the ‘Load’) can be displayed on
the controller by using a Eurotherm TE10 SSR fitted with intelligent current transformer,
PDCTX, or an SSR or contactor with an external PDCTX.
Load current monitoring and diagnostics may be used with any time proportioned output,
fitted in module position 1A, and uses the logic output wires which drive the SSR to return
signals back to the controller These signals represent the RMS value of the load current
during the ON period, or load related alarm conditions. It is not designed for analogue
outputs i.e. phase angle control.
It is also designed for single phase operation only.
There are two modes of operation:-
1. Mode 1
Detects if there is a break in the heater circuit. This includes heater or SSR open circuit. A
single Load Failure alarm message is displayed on the lower readout of the controller.
2. Mode 2
Provides the following:-
Display of true RMS load current On the
lower readout of the controller Displays the true RMS current in the ON
state to the load.
Low current alarm Analogous to Partial
Load Failure (PLF) supplied in some
Eurotherm SSRs Provides advanced warning of failure of
one or more heaters in parallel
High current alarm Activated when the
heater exceeds a set limit Typically used where element bunching
may occur
SSR short circuit This will apply full power to the heaters
which could result in an over temperature
condition. This alarm provides early
warning.
Heater failure Indicates open circuit load conditions