22BCCC

Terminal in Hz
Sampled Pulses for 1/2 Cycle of Z
(Gate/Reset) Pulse
2 1.25M
5 500K
10 250K
20 125K
50 50K
100 25K
10 Rockwell Automation Publication 1794-UM010D-EN-E - July 2013
Overview of the Very High Speed Counter Module
Operation of Scaler
In period/rate mode, the scaler lets the incoming pulse train at the Z (gate/reset)
terminal be divided by a user defined number. Acceptable values for the scaler are
1, 2, 4, 8, 16, 32, 64 and 128. There is one scaler value for each counter.
Connection to Counter Inputs
The only input to the module in the period/rate mode is made to the Z (gate/
reset) terminal. The counter inputs (channel A and B) are not used in the period/
rate mode.
Continuous/Rate Mode The continuous/rate mode is similar to the period/rate mode previously
described except the outputs in this mode are dynamic outputs. Use this mode to
determine the frequency of input pulses by counting the number of internal
5 MHz clock pulses over a user-specified number of input signal pulses. Each
output is turned on as soon as the turn-on count is reached, and turned off as
soon as the turn-off count is reached. As the internal 5 MHz clock is counted, the
outputs dynamically track the 5 MHz count. This allows you to turn an output
on a certain number of 5 MHz counts after the gate/reset pin goes active, and
turn it off a certain number of 5 MHz counts later.
1794-VHSC module counts the total number of pulses occurring at the Z (gate/
reset) terminal. This function is frequency-limited to 200 Hz X the scaler value.
This total count is returned in input file words 4 (LSW) and 5 (MSW) for
channel 0 and 6 (LSW) and 7 (MSW) for channel 1. You can reset this count by
setting the VR bit.
200 12.5K
500 5K
1 KHz 2.5K
2 KHz 1.25k
5 KHz 500
10 KHz 250
20 KHz 125
50 KHz 50
100 KHz 25
ATTENTION: Sample period times scaler must be less than 6.71 s in
order to avoid a zero frequency detect indication.
Relationship Between Sampled Pulses and Input Frequency
Input Frequency at Z
(Gate/Reset)
Terminal in Hz
Sampled Pulses for 1/2 Cycle of Z
(Gate/Reset) Pulse
Rockwell Automation Publication 1794-UM010D-EN-E - July 2013 11
Overview of the Very High Speed Counter Module
Period/Rate and Continuous/Rate Output Operation with Scaler of 1
Rate Measurement Mode Use the rate measurement mode to count incoming pulses for a user-specified
time interval. At the end of the interval, the module returns a value representing
the sampled number of pulses and a value indicating the incoming frequency.
When the count and frequency are updated, any associated outputs are checked
against their associated presets.
The value representing the total number of pulses is returned in input file words 4
(LSW) and 5 (MSW) for channel 0 and 6 (LSW) and 7 (MSW) for channel 1,
and the value indicating the incoming frequency is returned in words 0 (LSW)
and 1 (MSW) and 2 (LSW) and 3 (MSW). The total count equals the running
sum of the number of pulses received during the sample period. The operation of
rate measurement mode is shown in Figure Operation of the Rate Measurement
Mode on page 12.
Incoming pulse train at Z
(gate/reset terminal)
5 MHz internal clock
A (not used)
B (not used)
Input A
Input B
Z
Encoder/Pulse generator
1794-VHSC
Input Z
(Gate/Reset)
scaler
5 MHz clock
1
Accumulated count
Outputs updated continuously
Frequency
updated here
10 20
Assumes symmetrical pulse, 50% duty cycle, so period = sample time on X 2 (on and off)
Frequency = 1/period
If count = 25, scaler = 1, and clock period = (1/5 MHz)
Frequency = 1 / [(25/1) X (1/5 MHz) X 2] = 100 KHz
45894
12 Rockwell Automation Publication 1794-UM010D-EN-E - July 2013
Overview of the Very High Speed Counter Module
Operation of the Rate Measurement Mode
Sample Period
You can set the sample period used in the frequency calculation in the rate
measurement mode. Allowable values are 10 ms to 3 s in 10 ms increments. The
default value is 1 s.
Connection to Counter Inputs
The only user connections used in the rate measurement mode are to phase A of
the module. The Z (gate/reset) and channel B terminals are not used in
this mode.
Pulse Width Modulation The module can generate a pulse width modulation signal that may be tied to any
output. By specifying a period (configuration word 2) and gate interval
(configuration word 2 or 3) together with the PWM configuration word 2 or 3, a
counter and its first ON/OFF window comparator is assigned and the signal
generated. The actual duty cycle is specified by output words 2 and 3.
A Input
B (not used)
Input A
Input B
Z (not used)
Encoder/Pulse generator
1794-VHSC
Input Z (Gate/Reset) Time base
12 3
A Input (pulse)
Internal sampling gate
Accumulated count
Frequency calculated,
outputs updated here
If sample period is 50 ms, and count = 3, then frequency = 3/50 ms = 60 Hz 45895
EXAMPLE In , three counts have been accumulated during the user-selected time
period. If you had selected 50 ms as the sample period, the frequency
returned to the programmable controller processor would be:
Frequency = Counts/Sample period = 3 counts/50 ms = 60 Hz
Rockwell Automation Publication 1794-UM010D-EN-E - July 2013 13
Overview of the Very High Speed Counter Module
Outputs The 1794-VHSC module has 4 outputs, isolated in groups of 2. Each of the
outputs is capable of sourcing current and will operate between 5 and 24V DC.
You must connect an external power supply to each of the outputs. The outputs
can source 1 A DC alone or in combination. The outputs are hardware-driven
and will turn on in about 25 s when the appropriate count value has been reached.
Enabling and Forcing Outputs
Outputs may be forced on or off independent of count or frequency value. To
force the outputs, they must first be enabled. Enabling the outputs is done
through a data table word 1, bits 1, 5, 9 and 13 (see Figure 1794-VHSC — High
Speed Counter Module Image Table Mapping on page 35). once the outputs
have been enabled, they may be forced on by setting bits 0, 4, 8 or 12 in word 1.
The outputs can be forced off by setting the enable bit to 0.
Assigning Outputs to Counter Windows
By setting bits in the configuration block, you can assign the outputs on the
module to any of the various counter windows. You can assign any output to any
count window with no restrictions.
Operation of Outputs
When the outputs for the 1794-VHSC module are enabled and assigned to a
counter window they operate in an ON-OFF fashion. For example, assume that
the module were programmed to turn ON an output when a count value of 2000
was reached. Further, assume that the user desired to have the output remain
energized for a period of 3000 counts and then turn OFF. The end result would
be that the outputs would turn ON at count of 2000, would remain energized for
3000 additional counts, and would turn OFF at 5000 counts. The ON and OFF
values are circular around zero (see Figure On-Off Operation of Output on
page 13).
On-Off Operation of Output
Using output 0 as an example, when the value in Counter ON Value is less than
the value in Counter OFF Value, the output turns on at 2000 and off at 5000. If
the value in Counter ON Value is greater than the value in Counter OFF Value,
the output turns off at 2000 and on at 5000 (see Figure Effect of Values in On/
Off Operation on page 14).

通讯
轻松管理从车间到总部的信息，无缝地集成您的整个系
统，同时又能控制、配置和收集数据。
Allen-Bradley® PowerFlex系列变频器使用NetLinx开
放式网络架构，提供常用的功能和服务集，适用于在
EtherNet/IP™、DeviceNet™和ControlNet™中使用的通用
工业协议(CIP)。在单个网络上提供控制、配置和收集数据
的能力，简化工厂通讯，并可帮助降低总的拥有成本。
CIP是NetLinx开放式网络架构中的一个主要部件，为您提
供以下通用功能：
• 通用控制服务 – 为您提供一套标准的消息发送服务，
适用于NetLinx架构中的所有三种网络。
• 通用通讯服务 – 让您连接到任何网络，以及配置和收
集来自任何具有通用的路由功能的网络的数据。这在
系统配置过程中可节省时间和工作量，因为在网络之
间移动数据不需要路由表或添加逻辑。
• 通用基础知识 – 通过提供类似的配置工具和功能，减
少了在NetLinx架构内移动到不同网络时所需的培训工
作量。
除了NetLinx开放式网络架构以外，PowerFlex变频器能
够支持全世界现有的工业协议。参见4类和7类选项了解
详细信息。
性能强大，控制灵活。
6
源代码级集成
通过集成罗克韦尔自动化有限公司集成架构以及
PowerFlex变频器的高级功能，您可以在变频器和控制器
之间实现无人能比的集成水平。我们称之为“源代码级
集成”。
源代码级集成是指使用RSLogix™ 5000来配置变频器的能
力，可让用户将控制器编程、变频器系统配置、运行和维
护整合成单个集成的环境，帮助大大缩短编程和试车的时
间，还能将所需的软件工具数量降至低，从而降低总的
拥有成本。
7
8
线路和负载选项
典型变频器应用
性能强大，控制灵活。
产品选择工具箱
产品选择工具箱是一套产品选择和系统设计软件工具，
帮助您选择Allen-Bradley产品并使用这些产品来设计应
用解决方案。
通过这个工具，您可以为所有Allen-Bradley产品制作
一个物料单，配置电动机控制总线系统、电动机控制中
心、自动化系统和运动控制系统，并制作项目报价和提
交文档。
产品选择
• ProposalWorks中的变频器选择向导 – 选择一个低压变
频器
• Integrated Architecture Builder – 配置自动化系统
• CenterONE – 设计低压电动机控制中心
• MCS Star – 设计模块化电动机控制系统
系统设计和支持工具
• eCADWorks – 获得CAD图纸
• 运动控制分析器(MotionAnalyzer) – 适用于速度和定
位应用的设计工具
• Rail Builder – 设计DIN安装系统
PowerFlex加速器工具包
PowerFlex加速器工具包提供方便使用的工具和面板，帮
助您轻松设计、安装、运行和维护变频器系统。
• 样品面板布置 – 根据佳实践设计的预配置面板布
置，可进行修改以满足您的设备需要。CAD图纸从起点
开始提供，极大地缩短设计时间。
• 简化布线 – 布线图格式包括DWG、DFX、或PDF格式，
大大缩短在设计和面板布线上所花的时间。
• 预配置人机界面(HMI) – 利用预配置人机界面(HMI)面
板提供设备状态、控制和诊断，同时大大降低集成费
用，提高性能并加快上市时间。
• 预配置逻辑 – 预配置逻辑提供了PowerFlex变频器和人
机界面(HMI)面板之间的接口以及具体的应用逻辑，帮助
大大降低您的工程费用。

运动分析器
对于需要超过一个恒定负载和稳定速度的应用，运动控
制分析器软件可帮助您处理所需的复杂计算。运动控制
分析器采用方便使用的格式，对于包含PowerFlex变频器
或Kinetix®伺服驱动器的速度和定位应用来说可降低设
计风险。

imcmotion
9
10
PowerFlex 4交流变频器
该变频器旨在满足全球OEM和终用户在简单化和节省空间方面的要求，
提供了一些直观的功能，如带局部的电位计的集成化键盘和即装即用的控
制键。