GW Instek GDM-SC1A User manual

Scanner Card
GDM-SC1A
INSTALLATION GUIDE
REV. 01
ISO-9001 CERTIFIED MANUFACTURER

This manual contains proprietary information, which is protected by
copyrights. All rights are reserved. No part of this manual may be
photocopied, reproduced or translated to another language without
prior written consent of Good Will company.
The information in this manual was correct at the time of printing.
However, Good Will continues to improve products and reserves
the right to change specifications, equipment, and maintenance
procedures at any time without notice.
Good Will Instrument Co., Ltd.
No. 7-1, Jhongsing Rd., Tucheng Dist., New Taipei City, 236, Taiwan.

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SCANNER CARD
The optional scanner, GDM-SC1A, lets you
effectively measure multiple channels when
connected to a GDM-8255A, GDM-8261 or
GDM-8261A multimeter. Up to two GDM-SC1A
scanner cards can be installed into the GDM-8255A
or one GDM-SC1A into the GDM-8261 or
GDM-8261A. If two scanner cards are installed,
one can be selected as the master scanner, and the
other as the slave.
Scanner
Installation
Scanner Installation ................................................ 4
Select Channel group and enable scanner ............... 6
Connect wire.......................................................... 10
Scanner Configuration Record ............................... 14
Specification
Specifications ........................................................ 16
GDM-8255A Reading rates &Specifications........... 17
GDM-8261A Reading rates &Specifications........... 17
How to
Thermocouple
measurement
Thermocouple measurement ................................. 23
DMM_SCAN_CARD Software ................................ 26

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GDM-SC1A Basic Specifications
2-wire channel
16 pairs
Maximum current
2A (ch17, ch18)
4-wire channel
8 pairs
Resistance
2/4 wire
Single wire channel
N/A
Cold junction
Temperature
Sensors (Analog)
Maximum voltage
250V
Connection
Screw terminal
Scanner Installation
Configure scanner
Open
Scanner
cover
1. Take off four screws from the bottom panel of the
scanner.
2. Remove the top panel.

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3. Note the connection terminals.
Overview
16 general purpose channels are available, 8 on the left row,
8 on the right row. Current (ACI, DCI) measurement uses
2 extra channels. All channels are fully isolated (Hi and Lo).
Scan/Step
connection
Refer to the below table for measurement and test line
connection. Note: Not all items can be used with GDM-8255A.
Item
No. of wires
No. of channels
DCV, ACV
Diode/Continuity
Period/Frequency
2 wires (H, L)
16 (CH1 ~ 16)
DCI, ACI
2 wires (H, L)
2 (CH17, 18)
Maximum current : 2A
Temperature
simulation
Cold junction
(Separate Chapter)
2 wires (H, L)
2 wires (H, L)
16 (CH1 ~ 16) for
temperature
15(CH2~ 16) for
temperature, CH1 for
Cold junction
2W Resistance
Temp. 2W RTD
2 wires (H, L)
16 (CH1 ~ 16)
4W Resistance
Temp. 4W RTD
4 wires
(Input H, L
+ Sense H, L)
8 pairs (CH1 [input]&
9[sense], 2&10,....8&16)

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Select Channel group and enable scanner
Background
When 2 scanner modules are installed in the
GDM-8255A, 2 groups of 18 channels each are
available. The scanner modules have a jumper to
configure which scanner is for which group. If only
one scanner is installed, the scanner should always
be configured to group 1(CH101~CH118).
The GDM-8255A can have up to 2 scanner modules
installed, whilst the GDM-8261/GDM-8261A can
have only 1 scanner module installed.
Group1
CH101 ~ 118
Group2
CH201 ~ 218
Select group
(Jumper J8)
(Preset
MASTER)
Set the jumper J8 in the center of the board
accordingly. Move the jumper to the right for
selecting CH1xx (101 ~ 118), and move to the left
for selecting CH2xx (201 ~ 218). If two scanners
are installed, set one scanner to Master (CH1xx) and
the other to Slave. If only one scanner is installed,
set the jumper to Master.
CH201-218
SLAVE
CH101-118
MASTER
J8
SS

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Enable scanner
(Jumper J9)
(Preset Enabled)
Set the jumper J9 on the rear side of the board
accordingly. Move the jumper up to disable the
scanner, and down to enable the scanner.
Enable cold
junction points
(Jumper J10)
(Preset Disabled)
Set the jumper J10 on the Bottom left of the
board accordingly. Move the jumper up (COLD
COMPEN) for selecting CH1 to Enable the Cold
Junction, or down(CH1) for selecting CH1 to
Disabled the Cold Junction.
J10
COLD
COMPEN
CH1
J9
Disable
Enable

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Note
Do Not set the jumpers horizontally as the figure
below shown, which will Not enable the target
functions.
Erroneous
example

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Temperature sensor Calculation
Overview
The temperature sensor provides a positive slope
output of 10 mV / °C
Equation
The temperature sensor voltage output (Vout)
calculates given temperature (Ta):
Ta = (Vout –Voffs) / Tc (Equation)
where
• Vout is the temperature sensor voltage output for a
given temperature
• Ta is the given temperature °C
• Tc is the temperature coefficient 10mV/ °C
• Voffs is the temperature sensor voltage offset =
500mV
Example
The temperature sensor voltage 0.785V
Ta = (0.785 –0.5 ) / 0.01 = 28.5°C
The calculates given temperature 28.5°C

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Connect wire
Wire selection
Make sure the wires have at least the same Voltage and
Current capacity as the maximum ratings in the
measurement.
When measuring TC, it has the possibility that CH1 is
being regarded as cold junction. In order to prevent
conflicts, it is suggested initiating from CH2 for wiring.
Connection
1. Turn the screw left (loose) using the screw driver
and insert the wire. Turn the screw right (tight) and
secure the connection.
Tighten
Loosen Insert
2. Route the wires as follows, using the two openings
(left and right) at the front cover.