Yokogawa 202 Field Mounting Rate Totalizer - Manual (Page 5)

Introduction 1
1. INTRODUCTION
The Model 202D Rate Totaliser is a microprocessor based instrument which
accepts a frequency or pulse input from a wide range of flowmeters. The
instrument displays flow Rate, a Resettable Total and an Accumulated Total
directly in engineering units.
The instrument is compatible with a wide range of flowmeters. Links on the input
board enable the circuit to be configured for millivolt signals, reed switches, pulse
trains and most other signal types.
Three different versions of the Model 202D are available:
1. A Battery Powered Version with no output.
2. A DC Powered Version with either:
i. high and low flow alarms or
ii. a low flow alarm and pulse output.
3. A Loop Powered Version with 4-20mA output and alarms as above.
The instrument is fully programmable from the front panel; the user can program
scaling factors, decimal point positions, filter constants and timebase.
The Model 202D is an upgraded version of the Contrec Model 202. The
following improvements have been made in the Model 202D:
♦
The 202D output board can have both ALARMS and a 4-20mA OUTPUT.
♦
The voltage drop across the alarm outputs in the 202D is ONLY 0.8 VOLTS.
♦
The voltage supply for the DC and loop powered versions can go AS LOW AS
9 VOLTS.
♦
The 202D has an overall LOWER CURRENT CONSUMPTION than the
previous model with an IMPROVED BATTERY LIFE - the battery life in the
new model is typically 5 years regardless of the time the unit spends in
totalising mode.
♦
In the 4-20mA output version of the 202D, the ACCURACY HAS BEEN
IMPROVED to 0.05% of span and the linearity to 0.05% of span at 25
°
C.
♦
The millivolt input can accept signals AS LOW AS 15mV P-P.
♦
The 202D has a WIDE FREQUENCY RANGE - 0.01Hz to 10kHz.
♦
The 202D has a WIDER K-FACTOR RANGE - K-factors from 0.000001 to
999,999 can be programmed.