GE 90-30/20/Micro manual Using Coils, Types of Coils, Type of Coil Display Power to Coil Result

4

Using Coils

Coils are used to control discrete references. Conditional logic must be used to control the flow of power to a coil. Coils cause action directly; they do not pass power flow to the right. If additional logic in the program should be executed as a result of the coil condition, an internal reference should be used for that coil or a continuation coil/contact combination may be used.

Coils are always located at the rightmost position of a line of logic. A rung may contain up to eight coils.

The type of coil used will depend on the type of program action desired. The states of retentive coils are saved when power is cycled or when the PLC goes from STOP to RUN mode. The states of non-retentive coils are set to zero when power is cycled or the PLC goes from STOP to RUN mode.

Table 4-2. Types of Coils

Type of Coil	Display	Power to Coil	Result
Normally	—()—	ON	Set reference ON.
Open		OFF	Set reference OFF.
Negated	—(/)—	ON	Set reference OFF.
		OFF	Set reference ON.
Retentive	—(M)—	ON	Set reference ON, retentive.
		OFF	Set reference OFF, retentive.
Negated	—(/M)—	ON	Set reference OFF, retentive.
Retentive		OFF	Set reference ON, retentive.
Positive	—(−)—	OFF→ON	If reference is OFF,set it ON for one sweep.
Transition
Negative	—(↓)—	ON←OFF	If reference is OFF, set it ON for one sweep.
Transition
SET	—(S)—	ON	Set reference ON until reset OFF by —(R)—.
		OFF	Do not change the coil state.
RESET	—(R)—	ON	Set reference OFF until set ON by —(S)—.
		OFF	Do not change the coil state.
Retentive SET	—(SM)—	ON	Set reference ON until reset OFF by —(RM)—,
			retentive.
		OFF	Do not change the coil state.
Retentive	—(RM)—	ON	Set reference OFF until set ON by —(SM)—,
			retentive.
RESET		OFF	Do not change the coil state.
Continuation	——<+>	ON	Set next continuation contact ON.
Coil		OFF	Set next continuation contact OFF.

GFK-0467K Chapter 4 Series 90-30/20/Micro Instructions Set 4-3