Cable Selection And Wiring - AMC 210 Series Instructions Manual

AMC-210 Transmitter with external electrochemical sensor

4.2 CABLE SELECTION AND WIRING

Connection should be made using 2-conductor, shielded cable. For best signal transmission
and maximum noise rejection, run cable through steel conduit (cable must be grounded at the
monitor or power supply). Supply voltage can be measured at the transmitter (–, +) connections
at the supply source. For basic cable selection, between the source and transmitter, use a 250-
ohm load resistance, use the following chart:
WIRE GAUGE
MAXIMUM @12VDC
DISTANCE IN
FEET (METRES) @24VDC 15000 (4573) 23000 (7010)
For applications not covered by the above chart, an example is shown below for selecting the
right cable, using the graph of Figure 3 and the following formulas
Note: Some non-AMC equipment may not have the load resistance built in.
Example:
Calculations on the graph
Maximum resistance .... MR
Load resistance .......... LR
Known data
Power supply .............................. 17 VDC
Load resistance ........................... 180 Ohms
Wire gauge .................................20 AWG
Cable length / 1 Ohm resistance ..... 43.6 ft (13.3m) typical
Formula 1 : To determine remaining safe loop resistance.
Maximum resistance
Load resistance
Remaining resistance
Formula 2 : To determine maximum safe cable length allowed.
Remaining resistance
Cable length (for 1 Ohm)
Maximum safe cable length
Note:
If maximum safe cable length is insufficient, increase the power supply voltage and/or
reduce the load resistance.
AWG 22
1000 (305)
518 Ohms
- 180 Ohms
338 Ohms
x 43.6 Feet
20
1500 (457) 2500 (762)
38000 (11582) 57000 (17373)
338 Ohms
14,736 Feet
8
18 16
3800 (1158)