Models 947, 948 and 960 Leak Detectors Operations and Service Manual
D-3
D.2.2 BCD Discrete Output Parallel Interface (J121)
The discrete I/O DB25 connector is used to control operations via a PLC. Table D-3
provides the J121 DB25 BCD connections.
Table D-3
Optional BCD Discrete Output Parallel Interface (J121)
Pin
Signal Name
Momentary
or Level
Description
Input/
Output
1, 2, 24, 25
Ground for J121
20,21
+24 VDC for Output Sourcing
22
Analog Leak Rate
Analog Voltage
0 to 10 V signal that is
updated when in running
mode
Output
23
Analog Leak Rate
Analog Voltage
Return for pin 22
Output
19
Leak Rate Update Pulse
Output
Leak rate is updated on
falling edge and is stable
as long as output is low
Output
Mantissa
3
LSD A
Active High
BCD Leak Rate.
Output
4
LSD B
Active High
BCD Leak Rate.
Output
5
LSD C
Active High
BCD Leak Rate.
Output
6
LSD D
Active High
BCD Leak Rate.
Output
7
MSD A
Active High
BCD Leak Rate.
Output
8
MSD B
Active High
BCD Leak Rate.
Output
9
MSD C
Active High
BCD Leak Rate.
Output
10
MSD D
Active High
BCD Leak Rate.
Output
Exponent
11
LSD A
Active High
BCD Leak Rate.
Output
12
LSD B
Active High
BCD Leak Rate.
Output
13
LSD C
Active High
BCD Leak Rate.
Output
14
LSD D
Active High
BCD Leak Rate.
Output
15
MSD A
Active High
BCD Leak Rate.
Output
16
MSD B
Active High
BCD Leak Rate.
Output
17
MSD C
Active High
BCD Leak Rate.
Output
18
MSD D
Active High
BCD Leak Rate.
Output
