VELTRON DPT 2500
Air Monitor Corporation
116-045-10.P65 (6/99)
VELTRON DPT 2500
- IO&M Manual
SECTION 5 – CALIBRATION
9
5.3 – TRANSMITTER INPUT CALIBRATION
5.3.1
For Units With Positive or Negative Differential Pressure Spans
4.
Connect DMM, set to read to the nearest 0.001 VDC, across test points
TP0 COM
(black) and
TP1 XMIT 1
(brown)
on the main circuit board. See Figure 4.
5.
With zero input pressure to the VELTRON DPT 2500, verify the DMM reads 0.000 ± 0.001 VDC. If adjustment is
required, adjust
XMIT ZERO
(R37 on main circuit board) as needed.
6.
Verify the LCD display (if so equipped) reads 000 ± 001. Adjust as necessary using
ZERO
(R9 on display board).
See Figure 5.
7.
Connect DMM, set to read to the nearest 0.01 mADC, across
TP2 OUT+
(red) and
TP3 OUT-
(orange) on the main
board. DMM should read 4.00 ± 0.01 mADC. Adjust as necessary using
OUTPUT ZERO
(R13 on main board).
8.
Place zeroing valve to the Normal position and apply input pressure (as read on manometer) to the High port of the
VELTRON DPT 2500. Adjust pressure according to the following:
–
For positive differential pressure spans, use the span value as indicated on the label under “SPAN”.
–
For negative differential pressure spans, use the positive equivalent of the span value as indicated on the label
under “SPAN”.
Caution:
Adjust low pressure signal air to zero before connecting to the VELTRON DPT 2500. This will prevent
over-pressurizing and damaging the unit.
9.
Verify DMM reads 20.00 ± 0.01 mADC. Adjust as necessary using
XMIT SPAN
(R38 on main board).
10. Verify the LCD display (if so equipped) reads the desired full scale value ±001. Adjust as necessary using
SPAN
(R1 on display board).
11. Repeat steps 4 through 10 as necessary until no further adjustments are required to either zero or span.
12. Disconnect all test equipment, re-install High and Low pressure signal lines and close or reattach cover.
Figure 4
