Instruction Manual

1
1. THEORY OF OPERATION
The Alarm Expander Module (AEX) is an optional plug-in card for the ANAFAZE 8
PID that provides 22 discrete input/output lines and EEROM [memory] storage
capability for PID loop constants and output states.
Of the 22 I/O lines, six are dedicated as inputs while the remaining 16 are user-
selectable as inputs or outputs in groups of four. A combination of hardware jumpers and
software direction commands is used to dictate data direction.
Loop constants and output levels are read from the EEROM on power up. This removes
the need to download these values each time the process is started. At any time while
running the user may command the PID to save all current operating parameters to
EEROM storage for use as default values upon the next start-up.
The user may select one of two operational modes available: Automatic Alarm Mode and
I/O Control Mode.
1.1 AUTOMATIC ALARM MODE
In the automatic alarm mode lines 0 to 15 are defined as outputs providing a high and
low alarm signal for each of the eight loops on the ANAFAZE 8 PID. The user may set
the upper and lower alarm setpoints for each channel through software. Lines 16 to 21
are still available as inputs.