Liquid Controls SP720-2 - Manual (Page 2)

Sponsler, Inc. SP720-2 Transmitter pg 2 DOC# MN-720
SPECIFICATIONS
Temperature: Operating -40 to 85
°C
Storage -65 to 125
°C
Input Voltage: Minimum = 7V + (20mA X RL)
Maximum = 28V + (4mA X RL)
Protected against polarity reversal
Signal Input: Frequency 0-3500Hz with 50KHz Carrier
(Requires pickup coil 1-1.3mh)
Analog Output: 4mA @ 0Hz, 20mA @ desired full scale frequency
Full scale range = 35Hz-3500Hz selectable
Response time = 95% of change in 1 second
Linearity = .3% F/S
Tempco = <2% of reading over entire temperature range
Features: LED Signal Indicator
Mounts directly on flowmeter
Enclosure: FM Approved, CSA Certified
Class I Groups B, C, D
Class II Groups E, F, G
Weight 1.7 lbs.
The SP720-2 Loop Powered 2 Wire Modulated Carrier Amplifier 4-20mA Transmitter is a
unique meter mounted device designed to combine the advantages of the modulated carrier
principle with the convenience and accuracy of a loop powered 4-20mA transmitter. When
incorporated with a frequency-generating device such as a turbine flowmeter, data transmission
in a current format proportional to flow is obtainable.
The Modulated Carrier produces a carrier frequency in conjunction with a RF pickup coil,
detects and amplifies the shift in the carrier frequency (modulation) that occurs with the
passage of magnetic material and generates a squarewave pulse with each shift in carrier
frequency. The pulse’s frequency is proportional to the input frequency and is converted
linearly to a representative current output through a load. The full-scale frequency of 35-
3500Hz is selectable via S1. LED D1 illuminates when a signal is present.
The Modulated Carrier principle introduces no drag on the passing magnetic device. Therefore,
extension of the low end of a flowmeter’s nominal linear range is realized. This parameter is
particularly useful when measuring a low mass gas. Installation of the SP720-2 requires only 2
wires because it is a true 2-wire transmitter in that input power and analog output utilize the
same wires.