Sigma Operation Manual
Revision B
/
July 2020
Page 20 of 68
Operating Safety
The workcell has several safety features that protect the operator from hazards in normal
machine operation.
Warning! The safety features should NEVER be bypassed, disabled, or tampered with.
PVA is not responsible for any damage, mechanical or human, caused by changes or
destruction of any safety features.
Safety Circuit
The main power to the workcell is monitored and controlled by the safety circuit. The
safety circuit contains two relays under-voltage protection and one or more safety
devices. The relays are wired in a redundant manner. The tripping contacts of the relays
are connected in series so the safety circuit will disconnect power even if one of the relays
fails. The relays are self-checking with positive guided contacts electrically forced to
operate together. If one redundant relays fails or a safety switch is activated, the power
contacts are opened.
Polycarbonate and Safety Glass Guarding
The work area is enclosed with either polycarbonate or safety glass guarding. The front of
the workcell is either open, for the manual processing of parts, or has doors.
Doors
The doors on the workcell are monitored during the dispense cycle. If the door is opened
while the machine is in operation, this will trigger a pause on the machine.
Exhaust Fan
The exhaust flange should be connected to a duct system that can receive the required*
CFM (cubic feet per minute) while maintaining less than 1.0” H
2
O static pressure in the
duct. If airflow through the exhaust system is not sufficient, it will generate an error.