3
AMPTEC
MADE IN USA
RESEARCH
CAGE CODE 1CRL2
PHONE 800-350-5105
1
4 5
OP247 Adapter
FUSE -
2 ampere
3AG FAST BLO
RS232C
Interface
revision 2.0
V
HI
V
LO
I
HI
I
LO
AMPTEC 620A-4 REAR PANEL configured with Option "232", "247"
2
(not part of NSN 6625-01-460-1499NM package)
6
620A-4 Rear Panel with options RS232C I/O
The AMPTEC 620A-4 rear panel (shown above) may
contain many optional jacks, terminals, labels, and
stickers. Only the option "247" Continuous Isolated
Operating Power DC Adapter (item #1) plugs in the rear
panel jack for isolation and to continuously operate the
unit.
Item 2
is the fuse holder - replace with a 2 ampere 3 AG
type fast blow fuse (rarely needs replacing).
RS232C Serial Interface - Item # 3 is the safety isolated
RS232C serial I/O (9 pin D type Sub-min connector).
This RS232C Interface provides the meter’s resistance
measurements to a PLC fitted with a serial port. The
RS232C protocol settings should be 9600 Baud, 8
Bits, No parity, 1 Stop Bit, 9 pin D Sub-min
connection.
RS232C Command Set (Option 232)
(NOTE: All front panel range buttons must be de-
selected (press in halfway)
with all range pushbuttons
out
to disable with local lockout and enable RS232C
control.
Note commands are case sensitive
.
C Continuous Read Mode - RS232C I/O
outputs a
data string every A to D conversion cycle, approx
.
2.5
times per second.
S
Single Read Mode - RS232C I/O
outputs a
single data string upon reception of a “R” command.
R
Read -
Commands
RS232C I/O
to output a
single data string (1 resistance reading).
r
0
De-Selects all Ranges
r1
Selects the 20 Ohm Range
r2
Selects the 200 Ohm Range
r3
Selects the 2K Ohm Range
r4
Selects the 20K Ohm Range
V
Version
c
ommands board to output the firmware
version string.
Data Format -
The
RS232C I/O
outputs a data
string with the following format:
1.2345E+3 The measurement is always in Ohms
(where E+3 = 10
+3
scientific notation style)
. The
Exponent is defined below.
1.2345E+3 = 1.2345
KOhms
(where E
+3
=10
+3
).
1.3700E+1
=
13.700
Ohms
(where E
+1
=10
+1
)
Range
Exponent
20.0
Ohm
E+1
200.0 Ohm
E+2
2.0 K Ohm
E+3
20 K Ohm
E+4
An overrange condition is indicated by
9.9999E
nn..
Where nn is the selected resistance
range exponent. A Range Error is indicated by
x.xxxxERR.
Item # 4
is the unit’s serial number sticker.
Item # 5
is the gold plated 4 terminal rear terminal
strip (they are wired in parallel with the front termi-
nals). If a “2 wire ohms” connection is made then
the
V
high and
I
high terminals should be shorted
together, and the
V
low and
I
low terminals should
be shorted. The AMPTEC 620A-4 Voltage High,
Voltage low, Current high and Current low wires
are permanently connected to the gold plated rear
terminal strip ( seel labeled gold plated terminal
strip on rear panel).
Item #6 Calibration Sticker -
If the calibration
due date has expired (1 year) AMPTEC or a Cal.
Lab can contact to re-certify the AMPTEC 620A-4
Explosive Safety Ohmmeter/Igniter Tester. contact
AMPTEC customer service 001-512-858- 4045.
A
M
P
TE
C
6
2
0
A
4
S
e
ria
l
#
620A
4
-1
2
7
8
D
A
T
E
CA
TED
D
A
T
E
D
U
E
L
IB
R
A
2
3
J
U
N
E2
0
0
4
2
3
J
U
N
E2
0
0
5
C
E
R
TI
F
IED
B
Y
D
W
H
MODEL NUMBER
620A4
SERIAL NUMBER
620A4-1278
