Dwyer DPT User Manual

Page 3

BUTTON OPERATION

SWITCH FUNCTION

ERROR

Hysteresis function
If the system pressure fluctuates around the nominal value,
the hysteresis keeps the switch status of the outputs stable.
When the system pressure is rising, the output switches when it
reaches the respective set point (SP); if the pressure falls again,
the output switches back only if the reset point (RP) is reached.

Application example: loading an accumulator.
The shut-off valve loads up to 8o bar and then shuts off. When
70 bar is reached again, it switches on once more.

Window function
The window function allows the monitoring of a defined range.
If the system pressure is between the window high (FH) and the
window low (FL), the output is activated (NO) respective
deactivated (NC).

Delay times (0.00 to 50 s):
By this means unwanted pressure peaks of short duration or high
frequency can be filtered out.

The pressure must remain for at least this time to enable the
switch to operate. The switching output does not immediately
change its status when it reaches the switching event, but only
after the delay time has elapsed. If the switching event no longer
pertains when the delay time has elapsed, the switching output
does not change.

Display-Mode

Programming-Mode

short press:
Display units

short press:
- Menu up
- Increase parameter value

long press:
Run-through Parameter Info
1. UNIT + unit
2. SP1 / FH1 + value
3. RP1 / FL1 + value
4. SP2 / FH2 + value (optional)
5. RP2 / FL2 + value (optional)
6. LOW + value
7. HIGH + value
8. TAG + value (Only display when value set)

long press:
- Menu up
- Increase parameter value

short press:
Display units

short press:
- Menu down
- Decrease parameter value

long press:
Switch to Programming Mode
If the password is set to <> 0000, a pass
word will be requested. If authentication is
successful, then it enters the Program Mode,
otherwise it reverts to Display Mode.

long press:
- Menu down
- Decrease parameter value (Increment rate is time dependent)
long press (during Restart, keep pressed)

short press:
Display units

short press:
- Select Menu Item
- Confirmation of the entry (Parameter value)

short press (both keys at the same time):
Return to Display Mode

INFO

Error Display

Description

ATT1

On changing the Switch Point the system automatically reduces the Reset Point

ATT2

Zero Point adjustment error, current pressure is outside the limits

ATT3

Password entered for Menu access is incorrect

ERR

Internal error

Overpressure, measuring range exceeded > approx. 5% (Display blinks)

Underpressure, under measuring range < approx. 5% (Display blinks)

Acknowledgement of an Error Display by pressing the ˝Enter˝ key.

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