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GRT1-CT1(-1) Counter Units Section 7-4
Note Each command is executed only once when the command bit is turned ON.
Command bits are not reset automatically and must be reset by the user.
Make sure to reset the command bit after execution of the command has
been completed (i.e., after the corresponding Completed Flag has turned ON
in word m+2). Also, make sure that all command bits are OFF when the Unit
is started, including starting a new Unit after Unit replacement.
Input Data The following table describes the data input from Counter Unit to the Input
Area allocated in the Master. This data is used to monitor counter data and
Counter Unit operating status.
“m” is the first word in the Input Area allocated to the Counter Unit in the Mas-
ter.
n+2
(contin-
ued)
11 Reset Command Bit (See note.)
Turn ON this bit to reset the Present Counter Value to 0.
12 and
13
Output Control Bits
These bits control the digital output (OUT).
Bit: 13 12
0 0 = Digital output controlled by range (LL and UL).
0 1 = Digital output turned OFF.
1 0 = Digital output turned ON.
1 1 = Digital output turned ON.
14 and
15
Reserved.
Words Bits Definition
Word Bits Definition
m and
m+1
00 to 15 Counter Data
The data from the Counter Unit specified by the Register Selection Bits (bits 00 to 02 of word n+2)
when the Counter Data Display Command Bit (bit 04 of n+2) was last turned ON is displayed here.
Check the Display Register Indication Bits (bits 00 to 02 of word m+2) to verify what data is currently
displayed here.
m+2 00 to 02 Display Register Indication Bits
These bits indicate which register is displayed in words m and m+1.
Bit: 02 01 00
0 0 0 = Present Counter Value
0 0 1 = Present Frequency (frequency of A input signal in Hz)
0 1 0 = Capture Value Register
0 1 1 = Preset Value Register
1 0 0 = Range Value Register (LL)
1 0 1 = Range Value Register (UL)
1 1 0 = Not supported
1 1 1 = Not supported
“Not supported” means that no register is assigned to that bit combination.
03 Write Command Completed Flag
This flag turns ON when the Write Command has been completed (triggered by the Write Command
Bit, bit 03 of word n+2). This flag will turn OFF when the Write Command Bit is reset.
04 Multiple Commands Warning Flag
This flag will turn ON if more than one of the following bits was turned ON at the same time:
Word n+2, bits 03, 09, 10, and 11.
The commands will be executed but the results may be unexpected.
05 Reserved.
06 Underflow Flag
This flag will turn ON if the count value underflows. Counting will stop with the count value at the
lower limit. The lower limit is −2,147,483,648. To restart counting, preset or reset the counter value.
This flag will turn OFF when counting restarts.
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