VELTRON DPT
Air Monitor Corporation
116-009-70.P65 (09/18/09)
VELTRON DPT - IO&M Manual
6.3 – TRANSMITTER CALIBRATION (con't)
The VELTRON DPT output and optional display will be calibrated for minimum and maximum full scale differential
pressure.
6.3.2
For units with Bi-Polar Spans
1. At the Terminal board connect DMM, set to read to the nearest 0.001VDC, across test points
TP0 GND
(black) and
TP1 XMIT 1
(brown). See Figure 4.5.
2. Apply input pressure (as read on manometer) to the Low port of the VELTRON DPT. Adjust pressure to the
positive equivalent of the minimum (negative) calibrated span value as indicated on the Factory Set-Up Information
Sheet.
3. Verify the DMM reads 0.000 ±0.001 VDC. If adjustment is required, adjust
XMIT ZERO
(R5 on Terminal
board) as needed.
4. Verify the LCD display (if so equipped) reads the desired minimum process value. Adjust as necessary
using
ZERO
(R9 on Display board, see Figure 6.2) until desired reading ±001 is achieved.
5. Connect DMM, set to read to the nearest 0.01mADC, to terminals
±TEST OUTPUT
on Terminal board.
DMM should read 4.00 ±0.01mADC. Adjust as necessary using
OUTPUT ZERO
(R4 on Terminal board).
6. Disconnect pressure input from Low port and connect to the High port.
7
Adjust input pressure to the maximum (positive) calibrated span value as indicated on the Factory Set-Up
Information Sheet.
8. Verify DMM at
±TEST OUTPUT
terminals reads 20.00 ±0.01mADC. Adjust as necessary using
XMIT
SPAN
(R3 on Terminal board),
9. Verify the LCD display (if so equipped) reads the desired maximum process value. Adjust as necessary
using
SPAN
(R1 on Display board) until desired reading ±001 is achieved.
10. Repeat Steps 1 through 9 as necessary until no further adjustments are required to either zero or span.
11. Remove test equipment and replace terminal side and circuit side covers, taking care to ensure proper
seal.
6.4 – RESPANNING
The calibrated span of the VELTRON DPT can be adjusted between 40% and 100% of its natural span (see Factory
Set-Up Sheet for the natural span).
6.4.1
Determine if the new desired calibrated span is within 40% to 100% of the natural span.
– If it is, continue with this procedure.
– If it is not, contact the Air Monitor Service Department regarding replacing the transducer.
6.4.2
Follow Steps 1 through 5 of Section 6.3.1, but adjust the input pressure to the new desired calibrated span.
6.4.3
When performing Step 6 of Section 6.3.1, if R3 (XMIT SPAN) will not adjust output to 20.00mADC, then R1
(socketed resistor on Terminal board) will need to be replaced.
The approximate value of R1 needed to obtain the desired calibrated span can be calculated with the following
formulas;
For a 0.05" w.c. natural span:
R1 =
For all other natural spans:
R1 =
Select a standard resistor nearest in value to the value calculated above.
After R1 has been replaced with the appropriate value, repeat all of Section 6.3.1 to ensure proper calibration.
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SECTION 6 – CALIBRATION
Calibrated Span
0.05"
w.c.
x
100
Calibrated Span
Natural Span in IN w.c.
x
200
Содержание AMC POWER VELTRON DPT
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