Product Overview
GEM80-400
Page xxx
ALSPA GEM80-400 SERIES CONTROLLERS TECHNICAL MANUAL
Issue 3 04/99
The new System Log function records and time-stamps the last 100 system
events. These events are stored in the GEM
80-400 Processor Module's battery
backed memory, the time being provided by the integral real time clock.
System events include: Power on, power off, resetting of the real time clock,
clearing of the fault log, system error messages, system information messages,
and compilation error messages.
The contents of the System Log may be displayed, saved to a file, printed and
cleared by issuing a simple command from a suitable GEM
80 programming tool,
such as Gemesys 3.
The System Log is of assistance during the program development and
modification phases, as explained above, and during the normal operation of
the system as it provides the opportunity to maximise the plant run time without
losing vital diagnostic information that can now be investigated at a more
convenient time.
See also paragraph 3.4 of this section
7.5. Key
Switch
A security key switch is mounted on the front panel of the GEM
80-400 Processor
Module. The Key Switch governs the controller's mode of operation and has
three positions labelled as HALT, PROG and NORMAL.
Note...
In order to get the controller running, in addition to setting the Key Switch
to PROG or NORMAL, a suitable GEM
80 programming tool will be required, to
issue the run command.
HALT
When the Key Switch is moved to the HALT position, the controller will enter the
halted state and reject any subsequent instructions to run. If the controller was
running when the switch was moved to HALT, a message to this effect is put in to
the System Log.
PROG
With the Key Switch in the PROG position, all functions of the controller are
available. This position is intended to be used for commissioning and
maintenance of the user program.
NORMAL
As the name implies, this is the position that is suggested for the normal use of the
system. With the Key Switch in this position, the controller will prevent any
modification, via the programming ports, of the user program and data tables
(except M-tables). The controller will still accept Halt and Run commands, and
allow the user program to be archived and monitored.
