Hanna Instruments bl 7916 User Manual
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TERMINAL CONNECTIONS BL 7917
Pt100 (for BL 7916 only)
A 2-wire Pt100 can be connected to provide automatic temperature
compensation of the pH measurements. The pump is supplied with a
110 Ohm resistor connected to the 2 Pt100 terminals. This delivers a
fixed temperature compensation of 25°C (77°F). The Pt100 is recom-
mended only in special instances where very high accuracy is
absolutely necessary since the error is only 0.03 pH for a temperature
difference of 10°C in the pH 6 to 8 range. The error will consequently
be less than 0.09 pH at readings from pH 4 to 10 when the
temperature is in the 15°C (59°F) to 35°C (95°F) range.
compensation of the pH measurements. The pump is supplied with a
110 Ohm resistor connected to the 2 Pt100 terminals. This delivers a
fixed temperature compensation of 25°C (77°F). The Pt100 is recom-
mended only in special instances where very high accuracy is
absolutely necessary since the error is only 0.03 pH for a temperature
difference of 10°C in the pH 6 to 8 range. The error will consequently
be less than 0.09 pH at readings from pH 4 to 10 when the
temperature is in the 15°C (59°F) to 35°C (95°F) range.
PROPORTIONAL SETTING
The pump is supplied with a 10K resistor connected to these
terminals. With this value the pump works at 100% of the rating
when the difference between measure and setpoint is more than
150 mV (BL 7917) or 1.5 pH (BL 7916). It goes into proportional
dosing for values less than the above.
You can vary this hysteresis band by simply changing the resistor as
follows:
terminals. With this value the pump works at 100% of the rating
when the difference between measure and setpoint is more than
150 mV (BL 7917) or 1.5 pH (BL 7916). It goes into proportional
dosing for values less than the above.
You can vary this hysteresis band by simply changing the resistor as
follows:
BL 7916
BL 7917
0.50 pH
1.91 K
50 mV
1.91 K
1.00 pH
4.87 K
100 mV
4.87 K
1.50 pH
10 K
150 mV
10 K
2.00 pH
21 K
200 mV
21 K
LEVEL CONTROL
The pump is supplied with these two terminals short-circuited. A
contact coming from a level controller (e.g. HI 7871, HI 7873) can be
connected to these terminals. If this contact is closed, the pump works
normally. If it opens, the unit will not pump even if the controller
commands it.
contact coming from a level controller (e.g. HI 7871, HI 7873) can be
connected to these terminals. If this contact is closed, the pump works
normally. If it opens, the unit will not pump even if the controller
commands it.
OPERATIONAL GUIDE
• Unscrew and remove the transparent front panel cover and
gasket seal for access to the terminals.
• Remove the protective plastic plate covering the terminals by
removing the 2 screws on both sides of the plate.
TERMINAL CONNECTIONS BL 7916
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