Fault Monitoring - Printronix

P9212 Maintenance Manual

results in immediate movement. Other paper commands and status signals
are also passed through this port.
The 64180 interfaces through its second UART
Ribbon and Shuttle Motion
to the ribbon / shuttle processor (RSP) on the mechanism driver board. The
64180 begins all transactions on the serial interface.

Fault Monitoring

The RTPU 64180, the PFC 8032, and the RSP monitor different functions for
faults. The 64180 looks for hammer driver faults, shuttle stalls, and an open
platen. The PFC 8032 monitors paper out and the paper motion detector. The
RSP watches for faults in the motor drive circuits. The PFC and RSP report
errors to the 64180, which collates fault status and passes it on to the DPU
68010 processor.
The 64180 and FTIC check the
Hammer Bank and Hammer Driver Faults
hammer driver and hammer bank for faults on every shuttle stroke. Faults are
detected by circuits on the mechanism driver and hammer driver boards and
relayed to the CCB. Fault circuitry can detect rising temperatures in the coils.
One coil is checked on every shuttle stroke; therefore, 88 shuttle strokes are
required to check all coils. When the RTPU is notified of a fault, it sends a
message to the 68010. The hammer driver and mechanism driver boards also
continuously monitor for shorts in hammer driver circuits and cables. If they
detect currents that can harm the hammer bank, the +48 volt power supply is
shut down by "crowbar" circuitry within 70 milliseconds.
Paper Faults The PFC 8032 monitors paper faults and reports them to the
64180 through the eight bit parallel port they share. The PFC works with a
friction wheel paper motion detector and a reflective (optical) paper out
sensor. The sensors interface directly to the CCB; there are analog circuits on
the CCB to condition the sensor inputs.
The RSP monitors ribbon and shuttle faults and
Ribbon and Shuttle Faults
reports them to the 64180 over the serial interface.
Principles of Operation 2–25