Kurt J. Lesker 979 Series, Operation And Maintenance Manual

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20 Series 979 ATV Transducer
979 ATV Transducer Electrical Connections Table
The digital communications connections are pins 1 and 2. RS-485 uses pin 1
for RS485(-) and pin 2 for RS485(+).
Relay Inductive Loads and Arc Suppression
If using the set point relay to switch inductive loads (e.g., solenoids, relays,
transformers, etc.), the arcing of the relay contacts might interfere with 979
operation and reduce relay contact life. Therefore, an arc suppression
network, shown schematically below, is recommended.
The values of the capacitance C and the resistance R can be calculated by
the following equations:
C = I
2
/(1 x 10
7
)
R = E/ I
a
where:
C is in farads
R is in ohms
I is DC or Ac
peak
load current in amperes
E is DC or Ac
peak
source voltage in volts
a = 1 + (50/ E)
Note that R
min
= 0.5
Ω
and C
min
= 1.0 x 10-9 F
RELAY 2 N. O.
RELAY 1 N. C.
POWER + (24V)
POWER -
ANALOG OUT +
RELAY 1 N.O.
RS485 +
ANALOG OUT -
RS485 -
RELAY 1 COMMON
RELAY 3 N. C.
RELAY 2 N. C.
RELAY 3 N. O.
RELAY 2 COMMON
RELAY 3 COMMON
MALE CONNECTOR
ON 979
PIN 1
PIN 5
PIN 6 PIN 10
PIN 11 PIN 15