Digital Calibrator Digical 28530
The DigiCal 28530 is a portable, battery operated, precision instrument capable of sourcing and measuring mV/V/mA signals. Its range options with 3½ or 4½ digit LCD indicators cover a broad spectrum of instruments and process control systems with cost-effective calibration solutions. It can retain its precision over long periods of time in wide environmental conditions and a self-check facility monitors its performance and assures its dependability.
The 28530 is designed with field-proven circuit blocks using low-power integrated circuits. It operates on 7 AA size dry-cells or rechargeable AA size Ni-Cd cells or an external Battery Eliminator. The battery voltage is monitored to provide low battery indication. A current limited DC/DC converter provides operating power to the circuitry for operational safety in hazardous locations. An exceptionally stable voltage/current source provides continuously variable precision mV/V/mA output signals with two ten-turn potentiometers. With its unique operating controls and output terminals it can be used as a constant voltage/current regulator using external unregulated power supplies. It can also be used as a transmitter simulator in two-wire loops. The measuring circuit takes into account all possible error sources to ensure error-free measurement of sourced or measured signals. A precision 3½ or 4½ digit A/D converter provides a stable display with excellent repeatability. A self-check facility establishes correct functioning of all circuit blocks.
The Model 28530 is a general purpose calibrator which can be used either in the laboratory or taken around the plant for in-situ calibration of instruments and loops. It is specially designed for field use in commissioning and maintenance.
OUTPUT SPECIFICATIONS
The 28530 sources or measures mV/V/mA signals and simulates
2-wire transmitters. It can also supply 16V DC power to a
2-wire transmitter while measuring its output.
Range Options
A choice of several ranges to meet most common requirements
| I/O Code |
Function & Range Switches |
Resolution |
| A (3½) |
mV/mA |
200/20 |
(60 mA max) |
|
|
|
OPR/CH |
1 in 2,000 |
| B (3½) |
20 mA |
20 mV |
|
2V |
X1/X10 |
4/20 mA |
OPR/CH |
1 in 2,000 |
| D (4½) |
mV/mA |
200/20 |
(60 mA max) |
|
|
|
OPR/CH |
1 in 20,000 |
| E (4½) |
20 mA |
200 mV |
|
20V |
X1/X10 |
4/20 mA |
OPR/CH |
1 in 20,000 |
| F (4½) |
20 mA |
200 mV |
|
|
|
|
OPR/CH |
1 in 20,000 |
Notes:
1. X1/X10 multiplies range by 10 in Options B & E. Sourcing
Limited to 25mA/30V
2. 4/20mA Switch allows quick setting of 4mA or 20mA
Signal
3. Bold numbers indicate interlocked switches |
Output Impedance
| Voltage |
: |
< 0.05 ohm |
| Current |
: |
> 1 Megohm |
Source Capacity (@ 90% Bat Voltage)
| Voltage |
: |
20V into 1 KΩ OR 24V into 2 KΩ |
| Current |
: |
Upto 55 mA (Options A & D ) into 110 Ω R 20mA
into 800 Ω |
INPUT SPECIFICATIONS
Input Impedance
| Voltage |
: |
> 1 Megohm |
| Current |
: |
1 or 10 ohm depending on range |
Input Protection
Input/Output Terminals Protected for 30V DC in Voltage Ranges,
and upto double the range in mA Ranges
INDICATOR SPECIFICATIONS
Indicator Type
Indicators with the following resolutions to suit the selected
Range
| 3½ digit |
: |
12 mm LCD with a resolution of 1 in 2,000 |
| 4½ digit |
: |
8 mm LCD with a resolution of 1 in 20,000 |
INSTRUMENT ACCURACY
Accuracy at operating temperature between 22-32 °C, valid
within a one year Calibration Cycle
| 3½ digit |
: |
± 0.05% of rdg ± 0.02% of f.s. ± 1 dgt |
| 4½ digit |
: |
± 0.02% of rdg ± 0.01% of f.s. ± 2 dgt |
| Self-Check |
: |
Displays 1777±1 for 3½ and 17777±2 for 4½ dgt indicator |
POWER SUPPLY SPECIFICATIONS
Power Supply Options
| Option
A |
: |
7 Nos of AA size dry cells giving 10.5V |
| Option B |
: |
7 Nos of Ni-Cd Rechargeable AA cells giving 8.4V |
Battery Life
| Dry Cells |
: |
5 to 6 Hrs in continuous use at 12 mA output |
| Ni-Cd Cells |
: |
4 to 5 Hrs in continuous use at 12 mA output |
Low Battery
Indicated by lighting all decimals or "LO BAT" indicator
Mains Operation
A Jack is provided for operation on an external Battery
Eliminator
ENVIRONMENTAL SPECIFICATIONS
| Rated
Temp |
: |
5 to 55 °C |
| Humidity |
: |
Less than 90% RH ( Non-Condensing ) |
| Zero Drift |
: |
Less than 1dgt for every 10°C beyond the specified
ambient of 22-32 °C |
| Span Drift |
: |
Less than 0.0015% of rdg / °C |
| Storage Temp |
: |
0 to 70 °C (Without Batteries & Accessories) |
MECHANICAL SPECIFICATIONS
| Enclosure Size |
: |
125(W) x 200(H) x 60(D) mm |
| Enclosure Finish |
: |
Powder coated |
| Enclosure Weight |
: |
1.0 Kg (Without Batteries) |
STANDARD ACCESSORIES
Battery Eliminator, Probe Set, Leather Case, Wooden Case,
Instruction Manual, Warranty Certificate, Calibration Certificate
Traceable to NPL.
Charger for Ni-Cd Cells if Power Supply
Option B is selected.
ORDERING INFORMATION
While ordering please specify the various options as per
the following ordering code
| Model No. |
I/O Option Code |
P.S. Option Code |
| 28530 |
X |
X |
Example
Specify 28530AA to order the Digital Calibrator with 3½ digit
12mm LCD display and a range of 20mV, 200mV, 20mA, 200
mA operating on 7 Nos of AA size dry cells. |
