Omron E5ZD, Руководство по эксплуатации

Страница: 130 / 157

120
5-1 Writing Times
The time required from start of a transmission for a write operation to the point
where the data being written will affect operation is given below. Internal proces-
sing (the time required from reception of an command by the E5ZD to the start of
its response transmission) requires, for all commands but EEPROM Write, a
maximum of 130 ms + 20 ms
×
the number of data items for Fuzzy-logic Control-
lers and 50 ms for other Controllers. EEPROM Write can require up to a maxi-
mum of 3.5 seconds for internal processing for Fuzzy-logic Controllers; 2.3 se-
conds for other Controllers.
Time
+
Number of characters being sent 11 bits per character
baud rate
)
internal processing time
)
500 ms of arithmetic cycle time
For example, suppose we send the following command to write a set tempera-
ture of 100
°
C in memory bank 0 for control point 0 of unit 0 at a baud rate of 9,600
bps.
Each character consists of 11 bits (i.e., 1 start bit, 7 data bits, 1 parity bit, and 2
stop bits).
@ 0 0 W S 0 0 0 0 0 1 0 0 FCS * CR
The transmission includes a total of 17 characters (FCS would be two; CR, one).
Placing 17 into the above equation produces the following:
17 characters 11 bits per character
9.6 bits
[
20 ms
20 ms
)
(130 ms
)
20 ms )
)
500 ms
+
670 ms
20 ms
)
50 ms
)
500 ms
+
570 ms
Fuzzy-logic Controllers:
Other Controllers:
The new set temperature would thus come into use approximately 670 ms or
570 ms after the host computer began transmission of the command.
A minimum of 10 ms is required between receiving a response and sending the
next command.
5-2 Reading Times
The time required from start of a transmission for a read operation to the point
where the data being read is returned to the host computer is given below. Inter-
nal processing (the time required from reception of an command by the E5ZD to
the start of its response transmission) required, for all read commands,a maxi-
mum of 150 ms for Fuzzy-logic Controllers and 50 ms for other Controllers.
Time
+
internal processing time
)
500 ms of arithmetic cycle time
)
Number of characters being returned 11 bits per character
baud rate
For example, suppose we send the following command to read the measured
temperature for control point 0 of Unit 0 at a baud rate of 9,600 bps and the E5ZD
returns the response shown.
Each character consists of 11 bits (i.e. 1 start bit, 7 data bits, 1 parity bit, and 2
stop bits).
Reading Times
Section 5-2