Edwards Signaling AdaptaBeacons Technical Data
Technical Bulletin No.: 970524
Date: 2/4/00
Product: Chameleon
Product Category: AdaptaBeacons
Subject: PLC Connectivity of 103 Chameleon
The Chameleon 103I Series features an on-board processor with an internal
jumper, which allows the single unit to function as either a steady or flashing visual
signal. Either a PLC or contact closure can activate any one or all three lights.
The first light activated will illuminate either steady or flashing (determined by the
internal jumper position). When a second light is activated, the Chameleon cycles
between the two colors and activation of a third light causes it to cycle between all
three colors.
The 103 model performs similar to the 103I, but all signal operation in the
103 is controlled directly through a PLC’s ladder logic, rather than through the
Chameleon’s internal processor. The PLC will control which color LED’s are on,
how long they are on and whether they are steady-on or flashing.
For PLC connectivity, there are two considerations that need to be
addressed for proper operation of the Chameleon Multi-status Indicator. The first
consideration has to do with the type of output card utilized on your PLC. Both the
103 and the 103I require the PLC to have a Sinking Output card. For the
Chameleon to operate properly you must have a Sinking Output. The illustration
below shows a Sinking Output.
NOTE: It is important to make sure the Output Card on your PLC has a
Sinking Output.
Technical Bulletin # 970524 Page 1 of 4
The second consideration has to with 120VAC units. A resistor has to be
added to the circuit to eliminate any leakage current that can false activate the
Chameleon. The following calculation will guide you in determining the proper size
resistor to use with your specific PLC.
Step 1:
I
LPLC
– I
MLChameleon
+ 2 mA = I
Dissipated
Where;
I
= Leakage Current from your PLC
LPLC
I
MLChameleon
= Maximum Allowable
Leakage Current for the
Chameleon
2 mA = Tolerance Factor
I
Dissipated
= The amount of current to be
dissipated
Step 2:
V
Output
/ I
Dissipated
= R
Where;
V
= 120VAC Output from your PLC
Output
I
Dissipated
= The amount of current to be
dissipated
Step 3:
P = I
Dissipated
* V
Output
Where;
P = Wattage rating for your dissipating
resistor
= 120VAC Output from your PLC
V
Output
I
Dissipated
= The amount of current to be
dissipated
R = Resistor value to dissipate leakage
current
Example:
Your 120 VAC PLC output card has a leakage current of 15 mA. What size resistor will you
need to use to dissipate the leakage current?
Step 1:
I
LPLC
– I
MLChameleon
+ 2 mA = I
Dissipated
15 mA – 5 mA + 2 mA = 12 mA
Step 2:
V
Output
/ I
Dissipated
= R
120VAC / 12 mA = R
R = 10,000 ohms
Technical Bulletin # 970524 Page 2 of 4
Step 3:
P = I
Dissipated
* V
Output
P = 12 mA * 120 VAC
P = 1.44 watts
Therefore, your resistor needs to be
10,000 ohms and 1.5 watts.
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