96
Communication setup
8.3 4–20 mA option
The 4–20 mA option provides a current loop for controlling external devices such as a
chart recorder or PC. Either one or both of the 4–20 mA outputs can be factory installed
and are isolated from each other.
The interface has a 3 ft cable with a connector on one end, and a 10 ft cable with two
open wire leads on the other. Insert the connector into the sampler receptacle labeled
“Auxiliary”, located on the left side of the control housing. On the 10 ft cable, the wire with
clear insulation is positive (+) and the wire with black insulation is negative (–).
Rating:
•
Isolation Voltage:
Between sampler and either 4–20 mA output: 2500 V ac
Between the two 4–20 mA outputs: 1500 V ac
•
Maximum Resistive Load: 600 ohm
•
Output Voltage: 24 V dc - no load
Cable Required
4–20 mA Interface Cable (2924), 25 ft long, 4-pin connector on one end, tinned wire
leads on the other end.
8.3.1 4–20 mA programming
1.
From the Main Menu, select
OPTIONS, ADVANCED OPTIONS, 4–20 MA OUTPUTS,
SELECT
.
Note: When the 4–20 mA outputs are disabled and not completely turned off, they will continue to
output a steady 4 mA.
2.
Enable the 4–20 mA outputs by pressing
CHANGE CHOICE
while in the 4–20 mA
output menu.
3.
When the display shows the outputs as enabled, press
ACCEPT
.
4.
Choose either Output A or Output B. Use the
UP
and
DOWN
keys to highlight the
choice, then press
SELECT.
Table 16 4–20 mA Connections (J-18)
Pin
Signal Description
Wire Color
A
Output 1 + (pos)
Yellow
B
Output 1 – (neg)
Black
C
Output 2 + (pos)
Red
D
Output 2 – (neg)
Green
11:00 AM 21 - APR - 01
4–20 mA OUTPUTS
SELECT
OUTPUT A
OUTPUT B
RETURN
Goodnal STP ST041 Pre Treatment (Sigma 900 MAX All Weather Refrigerated Sampler) Vendor Manual
Q-Pulse Id VM373
Active 29/10/2013
Page 96 of 122
