1.3.Optional 4-20 mA Current Output
An option to the standard 0-5 VDC output is the 4-20 mA current output that is proportional to flow. The 4 - 20 mA signal is produced from the 0 - 5 VDC output of the Flowmeter. The current loop output is useful for remote applications where pickup noise could substantially affect the stability of the voltage output.
The current loop signal replaces the voltage output on pin 3 of the “Edge” connector. The current loop may be returned to either the power supply ground or the -15 VDC connections on the power supply. If the current loop is returned to the power supply ground, the load must be between 0 and 600 ohm. If it is returned to the -15VDC, the load must be between 600 and 1200 ohm. Failure to meet these conditions will cause failure of the loop transmitter.
The 4-20 mA I/O option can accept a current input. The 0-5 VDC command signal on pin A can be replaced by a 4-20mA command signal. The loop presets an impedance of 75 ohms and is returned to the power supply through the valve common.
1.4.Other Accessories
1.4.1. Hastings Power supplies
Hastings Power Pod power supply/display units are available in one and four channel versions. They convert 100, 115 or 230VAC to the ±15 VDC required to operate the flow meter and provide a digital indication of the flow rate. Interface terminals for the retransmission of the flow meter analog output signal are located on the rear of the panel.
The Power Pod 100 and 400 models are built with controllers in mind but will work with meters as well. The Model 40 is for flow meters only. Throughout this manual, when reference is made to a power supply, it is assumed the customer is using a Hastings power supply. Hastings PowerPod-100 and PowerPod-400 power supplies are CE marked, but the Model 40 does not meet CE standards at this time. The Model 40 and PowerPod-100 are not compatible with 4–20 mA analog signals. With the PowerPod 400, individual channels’ input signals, as well as their commands, become 4–20 mA compatible when selected. The PowerPod-400 also sports a Totalizer feature. More information about the Power Pods can be found on the Hastings web site. http://www.teledyne-hi.com/products/powerpod-series.htm
1.4.2. Interconnecting Cables
Cables are available from Hastings, in various lengths, to connect from the 15 pin "D" connector on the back of the Power Pod directly to any of the 200 series and 300 series flow instruments (including digital versions). More information about the available cables can be found in the Power Pod 400 bulletin on the Hastings web site. http://www.teledyne-hi.com/pdfs/bulletins.htm
HFM-E-200/HFC-E-202
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