Measurement Computing PML 1000 Operating Instructions Manual page 4

PML 1000 Operating Instructions
CONNECTING THE COMMUNICATIONS INTERFACE
The diagrams below show the connections necessary to interface your PML 1000 to a PC RS485 / 422 port or
to an RS485 to RS232 Converter. It is recommended that screened twisted pair cable be used for all
applications requiring cable lengths greater than 3m. It is also recommended that a 1200 termination resistor is
added to across each pair of wires at the furthest point from the master device. The shield of the cable should
be connected to the frame ground or ground connection of the master device. The diagram below shows the
wiring required for both 4 wire full duplex and 2 wire half duplex installations.
POWERING THE PML 1000
The PML 1000 is designed to operate from an AC supply with voltages in the range 90 - 26SV AC SO/60Hz
mains supply. The maximum power consumption is 20VA when all outputs are fully loaded and the display has
all segments illuminated.
WARNING - The PML 1000 is designed for installation in an enclosure, which provides adequate
protection against electric shock. Access to power terminals should be restricted to authorized skilled
personnel only. Application of supply voltages higher than those for which the PML 1000 is intended
may compromise safety and cause permanent damage.
The diagram below shows how the PML 1000 should be connected to the mains supply. Isolation should be
provided by a double pole switch and a Time delay 1A fuse.
APP-01025, Rev A
PML 1000 Operating Instructions www.meas-spec.com 1109
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