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201/203 Series Page 6 of 20
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 flow meter. 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 6 of the “D” connector. The current loop
may be returned to either the power supply ground or the -15 VDC connection 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 14 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. Totalizer (TR-1J)
The Hastings Flow Totalizer integrates the 0-5 VDC signal generated by the flow meter to give a
total flow reading. Count rates from 0 to 999 counts per minute are selectable by internal setting.
1.4.2. Hastings Model 40/200/400 Power Supply
Hastings power supplies are available in either two or four channel versions. They convert 115 or
230VAC to the ±15 VDC required to operate the flow meter. Interface terminals for the ±15 VDC
input and the 0-5 VDC linear output signal are located on the rear of the panel. Also, a cable can be
supplied with the power supply that provides the +15 VDC on pin 11 of a 15-pin “D” connector
and the 0 - 5VDC output measurement on pin 6. Pins 5, 7 and 12 are common, and pin 7 is chassis
ground. Throughout this manual, when reference is made to a power supply, it is assumed the
customer is using a Hastings Model 200/400/40 supply. Hastings power supplies do not meet CE
standards at this time.