Hioki RM3545, Instruction Manual, Page: 21 / 364

Operating Precautions
13
Before Connecting EXT I/O
To avoid electric shock or damage to the equipment, always observe
the following precautions when connecting to the EXT I/O connector.
•
Always turn off the main power switch on the instrument and on any
devices to be connected before making connections.
•
Be careful to avoid exceeding the ratings of external terminals (p.
204).
•
During operation, a wire becoming dislocated and contacting another
conductive object can be serious hazard. Use screws to secure the
external connectors.
•
The ISO_5V pin of the EXT I/O connector is a 5V (NPN)/ -5V (PNP)
power output. Do not apply external power to this pin. (External power
cannot be supplied to the instrument’s EXT I/O connector.)
To avoid damage to the instrument, observe the following cautions:
•
Do not apply voltage or current to the EXT I/O terminals that exceeds their
ratings.
•
When driving relays, be sure to install diodes to absorb counter-electromo-
tive force.
•
Be careful not to short-circuit ISO_5V to ISO_COM.
•
Configure the NPN/PNP setting to accommodate externally connected
equipment.
•
Do not operate the NPN/PNP switch while the instrument is on.
See: "Connector Type and Signal Pinouts" (p. 177)