CONTREX CX-1200 - Manual (Page 181)

5 - 88
The Basic Rung - Moving Bit Data
Since the PLC is based on bit data, a bit value is moved from one location to another. The most basic rung
(a normally open contact energizing a coil) is implemented in the PLC program by moving bit data.
LOAD 55 MaxFbSpd
OUT 101 DO_1
MaxFbSpd
55
DO_1
101
The value of MaxFbSpd bit (contact) is loaded into the Result Register (R) with the “LOAD 55 MaxFbSpd”
command and copied to the Digital Output DO_1 bit location (coil) with the “OUT” command. When the
MaxFbSpd bit is set (1), the DO_1 bit will get set also. As a result, the actual DO_1 pin will be active -
pulled low to sink current and possibly energize an external-relay coil. All rungs (groups of commands) must
start with a “LOAD” or “LD NOT” command and end with an “OUT” command. “LD NOT” starts the
rung with a normally-closed contact.
Since the “OUT” command does not change the value of the Result Register (R), you can move the result of
a rung to more than one Bit location without starting a new rung.
LOAD 15 DI_15
OUT 152 RstFI1Psn
OUT 153 RstFI2Psn
OUT 154 RstPsnErr
DI_15
15
RstFI1Psn
152
RstFI2Psn
153
RstPsnErr
154