Varec 8200, Инструкция по установке и эксплуатации, Страница: 25 / 38

Current Output Transmitter
Varec, Inc. 17
3 Configuration
3.1 Initial Checkout and Power-up
1. Recheck jumper selections.
2. Recheck wiring throughout the instrumentation loop.
3. Loosen the slotted drive coupling set screw using an Allen wrench. Set the transmitter to
the actual liquid level in the tank by rotating the field adjust knob located at the end of the
shaft.
4. Replace the explosion proof cover on the transmitter.
5. Bring one transmitter at a time online. Apply power.
6. Check that tank data is received and displayed correctly. At the 2500 ATG gaugehead,
rotate the check knob and determine that the receiving end of the instrumentation indicates
the check knob movement.
3.2 Calibration
The 8200 COT(s) are calibrated at the factory for full-scale operation. The scale of the
transmitter, however, can be set to any range between 45% and 100%. See Figure 3-1 on
page 18 for the calibration wiring and setup. Note that a power supply is needed for the
calibration procedure. If the transmitter does not have a Varec internal power supply, an
external power supply must be used for calibration.
Values without parentheses are for the 4 to 20 mA range. Values in parentheses are for the
10 – 50 mA range.
1. Place the transmitter on a work bench. (If a previously installed transmitter is being recali-
brated, only the encoder/electronics subassembly need be placed on the bench.)
2. See Figure 3-1 on page 18 and connect calibration equipment to the transmitter.
3. Turn the transmitter shaft until the transmitter encoder dial is set to zero.
4. Use a jeweler's screwdriver to adjust the trimmable resistor labeled ZERO. Adjust for a meter
current indication of 4 mA (10 mA).
5. Turn the transmitter shaft to set the transmitter dial to the maximum of the desired range.
The range can be set anywhere greater than or equal to 45% of the maximum.
6. Use the jeweler's screwdriver to adjust the trimmable resistor labeled SPAN. Adjust for a
meter current indication of 20 mA (50 mA).
7. Repeat steps 4 - 6 as needed.