Xylem CR500 CIRCULAR CHART RECORDERS - Manual (Page 13)

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RTD Input Wiring
RTD connections are shown in the previous, with the compensating lead connected to
terminal 4. For two-wire RTD inputs, terminals 2 and 4 should be linked. The three-wire
RTD offers the capability of lead resistance compensation provided that the three leads
are of same gauge and equal length.
Two-wire RTD should be avoided, if possible, for the purpose of accuracy. A 0.4 ohm
lead resistance of a two-wire RTD will produce 1 degree C temperature error.
Alarm Relays
If your recorder has the optional relay contacts installed, then terminal blocks J1 and J2
have been provided for connection to the relay on the microprocessor PC board of the
recorder.
Refer to Figure 2.4 (Page 11) for Single Pen Units.
Refer to Figure 2.6 (Page 12) for Dual Pen Ink and Thermal Units.
CAUTION! DO NOT TOUCH the terminals of the transformer while the recorder
is connected to the main AC power supply. To avoid the risk of possible electric shock,
unplug or disconnect the recorder from the main power supply before attempting to
access the terminals of the relay. If the recorder is installed with the battery back-up
option, disconnect the 9 Volt battery to avoid damaging the recorder and draining the
battery.
Your recorder will have a hinged chart plate held in place by two (2) screws located on
the right hand side of the chart plate. Remove these two screws and open the hinged chart
plate. If you are not sure how to access the back of the chart plate, please contact
GLOBAL WATER INSTRUMENTATION before continuing.
The relays are rated for the following maximum Values:
2.0 AMPS at 25VDC
1.0 AMP at 120VAC
Warning: Damage to the recorder may result if the ratings for the relays are exceeded.