Filter
Top Products
21
3-4 Special Relay (SR) Area
The SR area contains flags and control bits used for monitoring system op-
eration, accessing clock pulses, and signalling errors. SR area word ad-
dresses range from 18 through 19; bit addresses, from 1804 through 1907.
The following table lists the functions of SR area flags and control bits. Most
of these bits are described in more detail following the table.
Unless otherwise stated, flags are OFF until the specified condition arises,
when they are turned ON. Bits 1903 to 1907 are turned OFF when END is
executed at the end of each program cycle, and thus cannot be monitored on
the Programming Console. Other control bits are OFF until set by the user.
Word Bit Function
18 04 RDM(60) Reset Bit
05 RDM(60) Count Input Bit
06 RDM(60) Up/Down Selection Bit
07 HDM(61) Reset Bit
08 Battery Alarm flag
09 Cycle Time Error flag
10 High Speed Counter Reset
11 Step flag
12 Always OFF flag
13 Always ON flag
14 Always OFF flag
15 First Cycle flag
19 00 0.1-second Clock Pulse
01 0.2-second Clock Pulse
02 1-second Clock Pulse
03 Error (ER) flag
04 Carry (CY) flag
05 Greater Than (GR) flag
06 Equals (EQ) flag
07 Less Than (LE) flag
3-4-1 Battery Alarm Flag
SR bit 1808 turns ON if the voltage of the CPU backup battery drops. A volt-
age drop can be indicated by connecting the output of this bit to an external
indicating device such as a LED. This bit can be used in programming to acti-
vate an external warning for a low battery.
3-4-2 Cycle Time Error Flag
SR bit 1809 turns ON if the cycle time exceeds 100 ms. This bit is turned ON
when the cycle time is between 100 and 130 ms. The PC will still operate but
timing may become inaccurate. The PC will stop operating if the execution
time exceeds 130 ms.
3-4-3 High-speed Drum Counter Reset
SR bit 1810 turns ON for one cycle time when the hard reset signal (input
0001) is turned ON.
3-4-4 Clock Pulse Bits
Three clock pulses are available to control program timing. Each clock pulse
bit is ON for the first half of the rated pulse time, then OFF for the second
half. In other words, each clock pulse has a duty factor of 50%.
Special Relay (SR) Area Section 3-4