- 48 -
The LVDTs are aligned one at a time. The goal is to attain 2.50 +/- 0.02 VDC across the test
points for each LVDT. First, set SW3 and SW4 to the positions shown in the chart at line three,
“Aligning LVDT “A” Only”. Next, loosen the clamp screw slightly (see the following figure) to
loosen the LVDT and slide the LVDT up or down until the voltmeter reading is 2.50 +/- 0.02
VDC. DO NOT POUND ON THE LVDT! Now do the same procedure for LVDT B (and then C
and D for a WY20 scale). After the alignment is complete, the switches should be reset back to
line one or two in the chart depending on the scale at hand.
Pos 1
Pos 2
Pos 3
Pos 4
Pos 1
Pos 2
Pos 3
Pos 4
Pos 5
Pos 6
Pos 7
Pos 8
LVDT "A" and "B", WY10, WY10HD
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
LVDT "A" "B" "C" and "D", WY20
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
Aligning LVDT "A" Only
OFF
ON
ON
ON
OFF
ON
ON
ON
OFF
ON
ON
ON
Aligning LVDT "B" Only
ON
OFF
ON
ON
ON
OFF
ON
ON
ON
OFF
ON
ON
Aligning LVDT "C" Only
ON
ON
OFF
ON
ON
ON
OFF
ON
ON
ON
OFF
ON
Aligning LVDT "D" Only
ON
ON
ON
OFF
ON
ON
ON
OFF
ON
ON
ON
OFF
SW3 and SW4, LVDT Selection and Alignment Switches
SW3
SW4
7.03
Scale Calibration
Assuming all entered Parameters are correct, the scale is installed properly, and scales with
LVDTs are in alignment, the scale can now be calibrated. Without calibration, the scale will only
approximate the RATE.
Note that an AUTO ZERO must always be done before an AUTO
SPAN.
7.03.1 Auto Zero
AUTO ZERO is the first calibration step to perform. This is defined as the WP20 displaying zero
RATE when the belt is empty. With the conveyor running, press and hold the AUTO ZERO
button for five seconds. First, the message “HOLD TO ZERO” appears in the MODE window,
then the message “AUTO ZERO WAIT”. The WP20 will now do an AUTO ZERO for as many
belt revolutions as are specified in the Zero Revs Parameter (Section 6.02.12). A proper AUTO
ZERO should take a minimum of two minutes to complete, because the WP20 must “learn” what
an empty belt and zero-RATE “feels like”. When finished, the MODE window should revert
back to Units of Measure (typically Tons/Hour), and the RATE should go to zero and remain
there. An AUTO ZERO can be cancelled at any time by pressing RESET. If the message
“AUTO ZERO ERROR” appears during an AUTO ZERO, refer to Section 9 for troubleshooting
tips. Note that the RATE might wander above and below zero to some extent. After calibration is
complete, refer to Section 6.02.10 for AZT settings to eliminate this “zero bounce”.
LVDT
Clamp
screw
Clamp
Содержание Tecweigh 20
Страница 2: ... 1 ...
Страница 10: ... 9 2 09 I O Quick Reference Guide ...
Страница 20: ... 19 ...
Страница 24: ... 23 4 03 WY15 and WY25 Scale Wiring load cells ...
Страница 25: ... 24 4 04 HY15 and HY25 Field Wiring ...
Страница 26: ... 25 4 05 WY10 WY10HD and WY20 Scale Wiring LVDTs ...
Страница 27: ... 26 4 06 Chart Recorder Data Logger using the 4 20 ma output ...
Страница 28: ... 27 4 07 Chart Recorder Data Logger using the HFR output ...
Страница 29: ... 28 4 08 Remote Rate Total Display 4 09 Remote Tons Counter ...
Страница 30: ... 29 4 10 Radio Transceivers Local Scale Remote Processor ...
Страница 31: ... 30 4 11 Radio Transceivers Local Processor Remote PLC PC or Remote Display ...
Страница 32: ... 31 4 12 Radio Transceivers Local DC Generator Remote Processor ...
Страница 33: ... 32 4 13 Radio Transceivers Local DC Generator and Processor ...
Страница 34: ... 33 4 14 Multiple Processors to Tecweigh Multi Scale Display MSD ...
Страница 35: ... 34 4 15 Interposing Relay External 120 vac Power 4 16 Interposing Relay Internal 30 vdc Power ...
Страница 61: ... 60 SC300 PCB WY15 and WY25 SC400 PCB WY10 and WY20 ...
Страница 71: ... 70 10 01 WY10 Dimensions CHAPTER 10 DIMENSIONS ...
Страница 72: ... 71 10 02 WY10 HD Heavy Duty Dimensions ...
Страница 73: ... 72 10 03 WY15 Dimensions ...
Страница 74: ... 73 10 04 WY20 Dimensions ...
Страница 75: ... 74 10 05 WY25 Dimensions ...
Страница 76: ... 75 10 06 HY15 and 25 Dimensions ...
