VELTRON DPT 2500
Air Monitor Corporation
116-045-10.P65 (6/99)
VELTRON DPT 2500
- IO&M Manual
5.3 – TRANSMITTER INPUT CALIBRATION
5.3.2
For Units With Bi-Polar 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.
Place zeroing valve to the Normal position and apply input pressure (as read on manometer) to the Low port of the
VELTRON DPT 2500. Adjust pressure to the positive equivalent of the minimum (negative) 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.
6.
Verify the DMM reads 0.000 ± 0.001 VDC. If adjustment is required, adjust
XMIT ZERO
(R37 on main circuit board)
as needed.
7.
Verify the LCD display (if so equipped) reads the desired minimum process value ±001. Adjust as necessary using
ZERO
(R9 on display board). See Figure 5.
8.
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).
9.
Disconnect pressure input from Low port and connect to High port.
10. Adjust input pressure to the maximum (positive) span value as indicated on the label under “SPAN”.
11. Verify DMM reads 20.00 ± 0.01 mADC. Adjust as necessary using
XMIT SPAN
(R38 on main board).
12. Verify the LCD display (if so equipped) reads the desired full scale value ± 001. Adjust as necessary using
SPAN
(R1 on display board).
13. Repeat steps 4 through 12 as necessary until no further adjustments are required to either zero or span.
14. Disconnect all test equipment, re-install High and Low pressure signal lines and close or reattach cover.
Figure 5
10
SECTION 5 – CALIBRATION
