GHM DeltaOhm HD402 Series, Руководство по эксплуатации

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HD402…
- 7 -
V1.1
1 2 3 4 5 6
ON
+
RS485
OUTPUT
120 ohm
OPEN
RT
CAL ZERO
LED 485
ADDRESS SETTING
1 2 3 4 5 6
LCD
POWER
COM AUX
DIP SWITCH
POWER SUPPLY
& OUTPUT
NO NC COM +Vdc GND
B1
B2
1 2 3 4 5 6
ON
1 2 3 4 5 6
LCD
POWER LED ALARM LED
Models with digital RS485 output
(HD402ST…)
Models with relay switch output
(HD402TR…)
The instruments can be mounted in any position, but typically they are fixed on a ver-
tical wall with the pressure inputs facing down.
The deviation of the zero due to the mounting position can be corrected by using the
CAL ZERO button (except HD402TR…) or the B1 and B2 buttons (only HD402TR…).
In
the model HD402TR1L, an auto-zero circuit periodically automatically equalizes the
differential pressure at the input of the sensor and corrects the offset due to the
mounting position or sensor aging.
To manually calibrate the zero, disconnect both the tubes from the + and – pressure
inputs, then proceed as follows:
Zero manual calibration in the models with CAL ZERO button:
•
press CAL ZERO until the red LED starts flashing;
•
when the red LED turns off, the zeroing procedure is completed: reconnect the
tubes to the pressure inputs.
Zero manual calibration in the models HD402TR…:
•
Press B1 and B2 buttons at the same time until the ALARM red LED lights up (if it
was not already on because of an alarm condition) and the instrument displays the
model information and the UP and DOWN arrows on the left of the LCD.
•
When the instrument returns to the measurement mode displaying zero reading,
reconnect the tubes to the pressure inputs.
If necessary, the manual auto-zero procedure can be performed also in HD402TR1L
(in this case it is not necessary to disconnect the tubes from the pressure inputs).
Except for HD402TR1L (in which the auto-zero procedure is periodic and automatic), it
is recommended to follow the auto zero procedure at least once a year under normal
operating conditions.