User Guide

11
10
10. Output contacts:
– Two terminals marked "°C Sensor" for the connection of a
temperature probe for automatic temperature compensa-
tion
– Two terminals marked "mA Output" for the isolated output
BOTTOM CONNECTIONS
1. BNC socket for a combination pH electrode
2. Input voltage supply socket
3. Output voltage socket for acid dosing (supplies power to a
pump or electrovalve). This socket is activated by a relay
when the pH is higher than the "SET HI" value.
4. Output voltage socket for alkaline dosing (supplies power to a
pump or electrovalve). This socket is activated by a relay
when the pH value is lower than the "SET LO" value.
Unplug the instrument from the power supply before
replacing the fuse.
Specifications WM 8911D WM 8911U
RANGE 0.00 to 14.00 pH
RESOLUTION 0.01 pH
ACCURACY ±0.02 pH
(@20°C/68°F)
TYPICAL EMC ±0.1 pH
DEVIATION
mA OUTPUT User selectable 0 to 20 mA or 4 to 20 mA
in a 0-14 pH range with isolated output
OFFSET Through "OFFSET' trimmer
CALIBRATION (Max. ±1.5 pH regulation)
SLOPE Through "SLOPE" trimmer
CALIBRATION from 80% to 110%
TEMPERATURE Manual or automatic
COMPENSATION from -10 to 80°C (14 to 176°F)
SETPOINT RANGE From 0.00 to 14.00 pH with 2 trimmers:
"COARSE" for an approximate
regulation, "FINE" for fine tuning.
ALARM CONTACT Through a relay which provides a normally open
or a normally closed contact output (isolated
output Max.2A, Max.240V, resistive load, 1,000,000
strokes). The alarm contact will be activated if the
pH varies by -2.0 pH from "SET LO" and
+2.0 pH from "SET HI" points.
POWER SUPPLY 220/240V 110/115V
50/60Hz 50/60Hz
POWER SUPPLIES One plug for acid and another for alkaline dosage
FOR DOSING (115 or 220V, depending on the model,
Max.2A, 1,000,000 strokes)
ENVIRONMENT -10 to 50°C (14 to 122°F)
max. 85% RH non-condensing
PROTECTION IP54
WEIGHT 1.6 Kg (3.5 lb.)
ENCLOSURE 181 x 221 x 142mm (7.1 x 8.7 x 5.6")
MATERIAL Housed in rugged, fiber-reinforced polypropylene case