Xylem 3675 pH CONTROLLER - Manual (Page 4)

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II) Temperature Compensation
a) These meters are designed to be used with a PT-100 RTD temperature probe for
Automatic Temperature Compensation operations. The alpha value of PT-100
element is 0.00385.
A precision 0.1% resistor can be connected across the ATC input terminals to
simulate a fixed process temperature.
Table 1
Temperature °C Resistor value Ω
0 100.00
10 103.90
20 107.79
25 109.73
30 111.67
40 115.54
50 119.40
60 123.24
70 127.07
80 130.89
90 134.78
100 138.50
III) Rear Panel Connection
a) Connect the AC line to the rear terminals of the instrument. The instrument can be
powered by 115V AC or 230V AC, 50/60Hz. Make sure that the Earth terminal is
connected to the earth lead of the AC power line.
b) Connect the proper load to the output relays. Be sure that the load does not exceed
the relay rating, 5 Amp at 115V AC and 2.5 Amp at 230V AC for RESISTIVE
load only.
c) Set the pH/mV switch to the position for pH or mV operations.
d) Load Connections: Connect the proper load to the 4-20 mA output terminals.
Make sure that the load impedance is less then 550 Ω and the common mode
voltage does not exceed 500V DC.
e) Electrode Connections: If you are using a combination pH (mV) electrode,
connect the electrode cable to the pH/mV electrode BNC input connector. If you
are using separate pH (mV) electrode BNC input connector then connect the