Frequency Detection Function; Fetching The Value In A Hardware Counter - Delta DVP-ES2 Operation Manual

Function Group

Frequency Detection Function

Number M1357-M1359, D1056-D1059, D1246-D1247
Contents:
1. The special M devices and the Special D devices which are related to the frequency detection
function are listed below.
Pulse input
frequency detection
X0
X1
X2
2. The minimum input frequency which can be detected by the function is 0.5Hz (K500), the
maximum input frequency which can be detected by the function is 1KHz (K1000000). If the
input frequency is less than 0.5Hz, or there is no pulse input for more than 2 seconds, the
value in the corresponding special D device will automatically become 0. If the input frequency
exceeds 1KHz, the PLC will continue catch the input frequency. If the input frequency exceeds
the hardware specifications for the input, the PLC will not be able to catch the input frequency.
3. If the frequency detection function is disabled (the special M device is Off), the last value which
is stored in the special D device will be retained.
4. If the input frequency is less than 100Hz, the error will be less than one ten thousandth. If the
input frequency exceeds 100Hz, the error will become bigger, but the maximum error will not
exceed one one thousandth.
5. Difference between the frequency detection function and SPD: The frequency detection
function is mainly used to detect the frequencies less than 1KHz, and is used in the application
environments which need high precision (unit: 0.001Hz). For example, the frequency detection
function can be used to monitor the output frequency of a generator.
6. After the frequency detection function is enabled, the other functions of the input will not be
enabled. (For example, the external interrupt or SPD will not be enabled after the frequency
detection function is enabled.)
7. DVP-ES2/EX2 series PLCs (exclusive of DVP-ES2-C series PLCs) whose firmware version is
3.22 (or above), and DVP-SX2 series PLCs whose firmware version is 2.66 (or above) support
this function.
8. Example: Detecting X0's input frequency
Program in the PLC:
M0 M0
M0 M0
If X0' s input frequency is 50Hz, the 32-bit value in (D1057, D1056) will be K50000.
Function Group

Fetching the Value in a Hardware Counter

Number M1598-M1599, D1150-D1153
Contents:
1. The special M devices and the Special D devices which are related to the function of fetching
the value in a hardware counter are listed below.
Hardware counter
C243/C245/C246/C247/C248/C251/C252
C244/C249/C250/C253/C254
2. The function needs to be used with an external interrupt (X6 (I600/I601) or X7 (I700/I701)). The
value in a hardware counter is moved to a special D device when there is a transition in a
fetching signal from low to high or form high to low. The setting of an external interrupt
determines when the value in a hardware counter is moved to a special D device.
Enabling the Showing the input frequency
M1357 D1056/D1057 (32 bits)
M1358 D1058/D1059 (32 bits)
M1359 D1246/D1247 (32 bits)
DMOV K0 D1056 DMOV K0 D1056
M1357 M1357
Fetchinng
2 . Pr ogr am m i ng Conc e pts
(Unit: 0.001Hz)
Enabling the fetching
of the value in the
signal
hardware counter
X6 M1598
X7 M1599
Value which
is fetched
D1150/D1151
(32 bits)
D1152/D1153
(32 bits)
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