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How to use the electromagnetic flowmeter to introduce instructions

Use of electromagnetic flowmeter:
1.1 Wiring
The general process measurement instruments are two-wire instruments, and the power supply and signal share two wires. The electromagnetic flowmeter adopts four-wire system, and the power supply is separated from the signal line. It can be powered by DC or AC. The output signal has both current signal and pulse and alarm signal. When wiring, you must not connect the power supply and signal line. So as not to damage the flowmeter.
2.2 Parameter settings
The electromagnetic flowmeter calculates a volume flow rate from a small induced voltage corresponding to the flow velocity of the fluid, and outputs a signal of 4 to 20 mA. In order to ensure the correct signal, three parameters must be set before use, namely the path, meter factor and flow range. The first two parameters are already factory-calibrated, the user does not need to set, and the flow range is the output current. The instantaneous flow rate at 20 mA must be calibrated before use. In addition, the flow meter display mode, alarm mode, etc. must also be set. There are two ways to set the parameters of the flowmeter (configuration): one is to use the buttons on the display panel, and the other is to use the handheld smart terminal.
2.2.1 Panel button settings
The ADMAG AE (SE) series of electromagnetic flowmeters are generally equipped with a display panel with a 6-digit LCD display, 3 buttons and status indicators. All the parameters, such as display mode, display unit, and range, can be set by using the combination of the three keys SET, SHIFT and INC. The specific settings should refer to the manual of the electromagnetic flowmeter.
2.2.2 BT smart terminal settings
A meter with intelligent communication capability can communicate with a smart terminal. Huaneng's intelligent terminals are BT100, BT200 and other models, referred to as BT intelligent terminals, they use the BRAIN protocol, which will be 1 ± 2mA. The 2.4 kHz modulation signal is applied to an analog signal of 4 to 20 mA for signal transmission. Since the modulated signal is an alternating current signal, the superposition does not affect the value of the analog signal.
There are two ways to connect the BT intelligent terminal to the flowmeter: one is directly connected to the BT terminal under the flowmeter end cover. This method is suitable for on-site debugging or the flowmeter does not have intelligent communication function; the second is 4~20mA DC signal line connection, BT intelligent terminal can be connected anywhere from the control cabinet to the flowmeter signal line, the maximum distance can reach 2km, as long as the load resistance of the whole circuit is between 250~750Ω, it can be reliable Communication. In this way, the operator does not have to go to the site, and the flow meter can be set and monitored online in the control room, which is the most used method.
BT intelligent terminal adopts menu operation, which can display and modify various parameters of electromagnetic flowmeter at any time. The basic operations are as follows:
(1) Flowmeter self-test: Before any flowmeter is used or when it fails, it should first perform self-test. Using the self-test function of the flowmeter, you can understand the status of the flowmeter and determine the content and scope of the fault for maintenance and repair. maintain. Only instruments with normal self-tests can work normally.
(2) Range adjustment: Before and after using the flowmeter, the zero point and range must be adjusted to ensure that the 20mA of the flowmeter output corresponds to the maximum instantaneous flow. When there is no flow, the output is 4 mA, which is a 4-20 mA signal proportional to the flow rate, reducing measurement and conversion errors.
(3) Display mode setting: The display mode of the flow meter can be set as needed, such as the number of displayed digits, the displayed unit, the displayed instantaneous flow or cumulative flow, the size of the displayed value or its percentage, etc., the user can select according to the need. .
(4) Alarm setting: You can set the alarm current according to the need, select the alarm output mode, set the alarm status, etc., in order to remind the operator to deal with the flow in case of fault, to avoid further expansion.
(5) Other settings: The operator can also set the time constant of the flow meter according to the actual situation, eliminate the pulsating flow, change the flow direction of the liquid, etc.

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