Cooper Instruments DCM4800-1 Installation Manual

DCM 4800

LOAD CELL SUMMING TRANSMITTER

USER’S GUIDE

www.cooperinstruments.com

PH: 540-349-4746 • FAX: [phone]

CONTENTS

1.0 GENERAL DESCRIPTION.............................................................................................................. 3

1.1 Features ........................................................................................................................................................ 3

1.2 Application.................................................................................................................................................... 3

1.3 Brief Description.......................................................................................................................................... 3

1.4 Operation ...................................................................................................................................................... 3

1.5 Specifications............................................................................................................................................... 3

1.6 Instrument Layout ....................................................................................................................................... 5

2.0 INSTALLATION ............................................................................................................................... 5

2.1 Unpacking the DCM 4800 ........................................................................................................................... 5

2.2 Mounting ....................................................................................................................................................... 5

2.3 Electrical Connection.................................................................................................................................. 5

3.0 SETUP.............................................................................................................................................. 7

3.1 Setting the Excitation Voltage.................................................................................................................... 7

3.2 Single Load Cell System Adjustment....................................................................................................... 7

3.3 Multiple Load Cells Adjustment (Cornering the scale) .......................................................................... 8

3.4 Troubleshooting .......................................................................................................................................... 9

4.0 OPTIONS........................................................................................................................................ 10

4.1 Enclosures.................................................................................................................................................. 10

2. Dual Set Point Relays.................................................................................................................................. 10

5.0 WARRANTY REPAIR POLICY..................................................................................................... 10

CF 30 ii C0001 1.8.01

1.0 GENERAL DESCRIPTION

1.1 Features

• Summing of up to 4 load cells

• Complete strain gage bridge signal conditioner

• High gain, low drift, low temperature coefficient precision amplifiers, with low input current (10 pA typical)

• Wide input range from 5 mV to 50 mV full scale

• Very stable bridge balance with 80% tare offset capability

• 4-20 mA or 0-20 mA output

Capable of driving 1000 ohm loop

• 2 to 10 V or 0 to 10 V output

• Excitation supply capable of driving four load cells

o Typical 0.001% temperature coefficient
o Wide adjustment voltage range
o Long distance remote sense capability
o Very good line and load regulation

• Both AC & DC power capability
Surge voltage suppression

• Input, output and power three way isolation

• NEMA 4 enclosure for use in rugged environments

1.2 Application

• Precision weighing with load cells

• Process control add-on loops

• Can be used with all types of low output sensors

1.3 Brief Description

The DCM 4800 is an AC or DC powered Summing Transmitter for up to four load cells with output options of 0 to 20 mA,
and 0 to 10 V or 4 to 20 mA, and 2 to 10 V. All input/output options are included on one board so there is no need to
specify input/output parameters with the DCM 4800.

The DCM 4800 has a built in excitation supply capable of delivering up to 120 mA from 5 to 10 V, more than enough
current to drive four 350 ohm load cells.

The DCM 4800 offers three way isolation, input to output and power, eliminating unwanted ground loop problems. Overall
accuracy over the normal room temperature range is excellent at <±0.1% of full scale. The high gain, very low drift and
very low temperature coefficient of the DCM 4800 amplifier allows full scale live load signals as low as 5 mV to be
amplified to 20 mA or 10 V.

Designed with large and very stable tare offset requirements in mind, the 4800 can tare off up to 80 % of the output of a 3
mV/V load cell (at 10 V excitation).

If high/low setpoint alarms/controls are desired, the 4800 board is laid out to accept Opto-22 output relays. Potentiometers
are accessible to adjust the high and low trip points.

1.4 Operation

The 4800 accepts DC mV signals from up to four load cells which are summed together, then amplified, isolated and
filtered. The 4800 features a very stable on-board excitation supply and precision amplifier. They are designed for very low
drift and a small temperature coefficient, critical for high accuracy. The full scale output is either 20 mA or a 10 V signal for
industrial control. A wide AC and DC power voltage range is allowed for convenience.

1.5 Specifications

NOTE: Unless otherwise noted, specifications apply after half hour warm up at 23°C ±2 °C ambient. Temperature
Coefficients apply between 0°C and 55°C ambient.

CF 30 3 C0001 1.8.01

ACCURACY

10 TO 30oC, at 10 V Excitation Less than ±0.1%
Total Temperature Coefficient (TC) 0.0025%/oC typ

ISOLATION

AC or DC Powered – Three Way Isolated
AC to Input and Output 750 VAC

DC to Input to Output

300 VDC
500 pF

AMPLIFIER SECTION

Gain

Input Range 5 mV to 50 mV Full Scale
Linearity ±0.01% of Full Scale
TC 0.0015%/oC typ

Input Noise – 0.1 Hz to 10 Hz 2µV PP
Tare Adjustment Range

(Bridge Offset)
(Equals 80% F.S. of 3 mV/V cell at 10 V)

-3 mV to +6.5 mV
+6.5 mV to +16 mV
+16 mV to +25 mV

Temperature Coefficient 0.0015%/oC typ

Common Mode Rejection
Common Mode Input Voltage

100 dB Min
+5 Volts Max

OUTPUT

Zero Selection

Temperature Coefficient
Test Signal Output
Current Output Span

Current

Compliance Voltage

0 or 4 mA
0 or 2 V

0.001%/

o

C typ

Add 8 mA or 4 V to output

0 or 4 to +20 mA
Available 0 to -0.3 mA for zero monitor
0 to +20 Volts
Available 0 to -0.3 V for zero monitor

Loop Resistance 0 to 1000 ohms

Voltage Output Span

Voltage 0 or 2 to 10 V
Maximum Load Current 5 mA

Frequency Response

2 Poll roll off -dB at 10 Hz typ
Response Time
Rise Time 10% to 90%
To 0.1% of Final value

35 mS
100 mS

COMPARATOR OUTPUT Optional with Opto22 I/O Module

Comparative Voltage
Hysteresis Voltage
Comparator Output
Input/Output Isolation

BRIDGE EXCITATION SUPPLY

Voltage Adjustment Range
Temperature Coefficient
Load Current
Remote Sense for Excitation Supply

Current Leads Volt Drop

0 to 10 V

0.07 V typ
See the specification of OPTO22 output module
300 V

5 to 10 V

0.001% typ at 10 V
0 to 120 mA

Max 1 V drop

Sensing Leads Resistance Max 1 kohm

Line Regulation
Load Regulation
Output Noise

120 Hz Bandwidth

Less than 0.01%, typ 0.002%
Less than 0.03%, typ 0.005%

1 mV RMS, typ

CF 30 4 C0001 1.8.01