KEPCO TMA VXI-27 - Manual (Page 18)

TMA VXI -27 101602
3-1
SECTION 3 - OPERATION
3.1 LOCAL OPERATION
There is no local operation of the TMA VXI-27 controller; however, the controller provides three
front panel LEDs (see PAR. 3.1.1) and three auxiliary functions (see PAR.3.1.2) to the user in
addition to the remote programming capability described in PAR.’s 3.2 through 3.5.
3.1.1 FRONT PANEL INDICATORS
The TMA VXI-27 is equipped with 3 front panel LEDs which have the following functions: (see
Figure 2-2)
a. ONLINE. The top LED (for vertically mounted unit), green colored, indicates that the power is
applied and the internal microsystem is ON LINE. It is turned ON by an output port instruc-
tion executed by the internal microprocessor.
b. ACCESS. The middle position LED, green colored, indicates that a VXI ACCESS cycle to
address the module has been executed.
c. FAILED. The bottom LED (for vertically mounted unit), red colored, indicates the FAILED
condition. It is on during the power-up self test which is executed by the module every time
the power is first applied or after a hardware reset. The VXI standard requires that this LED
go off within 5 seconds. If this LED is still ON after 5 seconds, the VXI module is defective
and has to be serviced.
3.1.2 AUXILIARY SIGNALS
The AUX SIGNALS connector (see Table 2-1 and Figure 2-2) at the front panel provides the fol-
lowing auxiliary functions: emergency output shutdown, discrete fault, and +5V output.
3.1.2.1 EMERGENCY OUTPUT SHUTDOWN
The emergency output shutdown function allows the user to reset all the power modules con-
nected to the Control Bus with a single discrete signal. A user-initiated emergency shutdown
activates the non-maskable interrupt of the microsystem, forcing the microsystem to send a
reset to all power modules connected to the Control Bus. The NON-ISOLATED EMERGENCY
SHUT-DOWN INPUT accepts a TTL input signal to initiate shutdown; this signal is referred to
signal common. The ISOLATED EMERGENCY SHUT-DOWN INPUT requires a 2-wire isolated
signal and return path.
3.1.2.2 DISCRETE FAULT LINE
The DISCRETE FAULT LINE function provides a discrete controller fault indication by means of
an internal relay. The DISCRETE FAULT LINE relay contacts are open (open circuit between
DISCRETE FAULT LINE PIN 1 and PIN 2) if the internal microsystem is functioning normally;
this is accomplished by monitoring a pulse generated in the timer interrupt routine. If the micro-
system is not functioning normally, or a catastrophic condition appears on one of the power
modules, the contacts will close. The contacts reopen when the catastrophic condition disap-
pears and either the error buffer has been read (if the Command Language is CIIL) or when the
Device Dependent Error from the Event Status Register has been read (if the Command Lan-
guage is SCPI).