Chapter 3 Electrical Installation; Cable Length Ttl Mode; Cable Length Open Collector Mode - Emerson Daniel 3410 Series Installation Manual

Installation manual
DAN-20057315
3 Electrical installation
3.1

Cable length TTL mode

The maximum cable length is 2000 feet when the Digital Output "TTL" mode is selected.
3.2

Cable length Open Collector mode

For the Digital Output "open collector" mode, the maximum cable length depends on the
cable parameters, pull-up resistance used, the maximum frequency to output, and
frequency input parameters being driven. The following table provides estimated cable
lengths for different pull-up resistor values and different Max Frequency settings in the
meter using the following cable parameters. The table also provides an estimated cable
voltage drop which indicates how much voltage will be across the cabling and effectively
indicates to what voltage level the frequency input can be pulled down to by the
frequency output.
If the voltage drop is higher than the voltage required for the frequency input to see a low
state, then the configuration will most likely not work for your system. Performance of
frequency outputs will vary from this table with setup and frequency input being driven.
Table 3-1: Configurations for open collector frequency outputs
Cable
Length
(x1000ft)
0.5
1
2
4
0.5
1
1.7
6.5
The 22 AWG wire characteristics:
• Capacitance = 20 pF/ft or 20 nF/1000 ft (between two wires)
• Resistance = 0.0168 Ohms/ft or 16.8 Ohms/1000 ft
• Pull-up voltage = 24 VDC
Model 3418 GUSM
Cable Cable Pull-up
resistance resistance
(2 Capacitan Resistance Resistance Frequency Current
Conductor ce
s)
Ω nF Ω
16.8 10.00 1000
33.6 20.00 1000
67.2 40.00 1000
134.4 80.00 1000
16.8 10.00 500
33.6 20.00 500
57.12 34.00 500
218.4 130.00 500
Electrical installation
Total Maximu Sink
m
frequency
Ω (Hz) (A)
1016.8 5000 0.024
1033.6 1000 0.023
1067.2 1000 0.022
1134.4 1000 0.021
516.8 5000 0.046
533.6 5000 0.045
557.12 5000 0.043
718.4 1000 0.033
June 2019
Cable
voltage
drop
(2
Conductor
s)
VDC
0.397
0.780
1.511
2.843
0.780
1.511
2.461
7.296
47