HK Instruments DPI+/-500-D User manual

DIFFERENTIAL PRESSURE INDICATOR
DPI
Model summary
Each device has 4 selectable measuring ranges. Each device is individually temperature compensated.
4 range model
- AZ for autozero element*
- 2R for 2 relays
- for display
range
1
range
2
range range
4
Accuracy %/FS **)
Within operation
temp.-10…+50°C
Long term stability
typical 1 year
-AZ without -AZ
PI+/-500 (-AZ-2R) - ±100Pa ±250Pa ±300Pa ±500Pa ±0,7% (±1,5% initial) ≤ ± 1 Pa ≤ ± 8 Pa
PI2500 (-AZ-2R) - 100Pa 250Pa 1000Pa 2500Pa ±0,7% (±1,5% initial) ≤ ± 1 Pa ≤ ± 8 Pa
*) -AZ model recommended when measuring pressures below 250 Pa.
**) %/FS from highest pressure range (including: general accuracy, temperature drift, linearity, hysteresis and repetition
error).
Initial value is the factory calibration accuracy, better accuracy can be achieved with span point calibration.
The device has 0…10V output and 1 or 2 relay outputs (depending on the model).
The ifferential Pressure Indicator is delivered individually packed with standard accessories (see
accessories).

Technical data
Bursting pressure 30 kPa
Suitable media Air and non-aggressive gases
Measuring element Piezoresistive
Electrical interface Supply voltage 21-35V C/24VAC ± 10%,
with AZ option 24V C/VAC ± 10%
Current consumption 35mA + relays (7mA each) + AZ (20mA) +
0…10V output (10mA)
Output signals, basic version
Relay output (250VAC / 30V C / 6A)
0…10V, L min 1kΩ
Output signals, 2R version
Relay output 1 (250VAC / 30V C / 6A)
Relay output 2 (250VAC / 30V C / 6A)
0…10V, L min 1kΩ
Materials Housing ABS
Cover PC
Pressure connections ABS
uct connectors ABS
Tubing PVC, soft
Connections Electrical connections
Power and 0…10V out 3 x screw terminals, max 1.5 mm
2
Relays 2 x SP T 6 x screw terminals, max 1.5 mm
2
Cable entries M16 and M20
Pressure connections Male ∅ 5,0 mm and 6,3 mm
Weight 150 grams, with accessories 290 grams
Dimensions 90,0 x 71,5 x 36,0 mm
General ambient condition
Temperature range
Operation -10…+50°C (-5…+50°C for –AZ model)
Storage -20…+70°C
Ambient humidity 0 to 95% RH
Safety Protection standard IP54
Conformance Meets the requirements for CE marking:
EMC directive 89/336/EEC
Rohs irective 2002/95/EY
Accessories Standard accessories: Optional accessories:
o 2 fixing screws * Metallic duct connector
o 2 plastic duct connectors
o 2 m tube ∅ 4 / 7 mm

Dimensions

Installation
Notes when using high voltage for relays (115VAC…250VAC)!
The supply cable and control cable for relays should be separate if high voltage (115…250VAC) is used in
relay contacts. Both of the cables have their own cable entry.
Electrical connection diagram
The settings are done according to the instructions below:

Zero point adjustment
Note! Supply voltage must be connected one hour before the 0-point adjustment is carried out.
1) isconnect both tubes from the pressure inlets + and –
2) Push both arrow buttons or select “Zero” from the menu  green led turns
off and “Zero” text followed by a counter from 3 to 0 seconds is displayed
3) Wait until the green led turns on again and then connect the tubes back to
the pressure inlets
It is recommended to adjust the zero point every 12 months during normal operation.
* If the transmitter is equipped with automatic zero element the manual push button adjustment is not required.
* Auto zero element
Optional auto zero element makes the PI maintenance free of periodical push button zeroing. The AZ
element automatically adjusts the zero point of the transmitter from time to time; this eliminates the zero
point long term drift of the piezo resistive sensing element.
Zero point adjustment takes about 4 seconds to perform and it is carried out every 10 minutes. Initially
after power on, zero point is adjusted more often. After some time it is carried out every 10 minutes.
uring zero point adjustment the 0...10V output and relay outputs maintain their values and the display
shows “zero” text.
If zero point is adjusted manually there is no need to disconnect the tubes when transmitter is equipped
with the auto zero element.

High point adjustment (span)
Note! Supply voltage should be connected one hour before the span point adjustment is carried out.
Note! Span point must not be adjusted without input pressure. If the span point is adjusted with 0 Pa or
close to 0 Pa input pressure the device may lose its accuracy and will not give out correct readings. In this
case go to menu and select “Span” and then “Reset”. This resets the span adjustment.
To adjust the span you need an accurate reference meter.
Follow these steps to correctly adjust the span
1. Set the zero point *
2. Connect the input pressure
3. From the menu select “Span” and then “Adjust”
4. Adjust the display or 0…10V value to match the reference meter’s value using the arrow buttons and
confirm by pressing OK
*see section “Zero point adjustment”
How span adjustment affects the measurement