United Security Products AVD-45c Manuál stáhnout pdf (Strana 222)

208 UDC 6300 Process Controller Product Manual 1/03

5.21 Input 5 - Pulse Input

Introduction

This pulse input counts pulses sent from a 2-wire, 3-wire, or externally

powered external pulse device. The circuit is on an optional printed wiring

board which mounts to the Digital I/O board. This option is mutually

exclusive with the low level input board.

The input can be used as either a frequency input or as a pulse input. The

pulse input can be a pulse train or a method of adjusting the Remote

setpoint value up or down. Minimum Span = 100Hz; Resolution:±5Hz.

Frequency Input

This selection is normally used with frequency output devices, such as

Turbine Flowmeters. For this configuration, the controller counts the

number of pulses received over 1/3 second period then multiplies this

value by three to convert to Hertz (cycles per second). This conversion is

done so that the pulse input will operate at the same Loop sample rate as

the rest of the controller. The frequency range is 0 to 25,000 Hz maximum

and

0–100 Hz Minimum Span.

Pulse Input

There are two pulse input selections from which to choose:

• REMOTE SETPOINT PULSE TRAIN - The controller counts the total

number of pulses received, scales the value of each pulse by the

calibration values and the Input 5 High and Low range values, and then

sets the remote setpoint (RSP). For example: If the pulse input was

calibrated for 0 Hz (zero value) to 10,000 Hz (span Value) and the Input

5 high and low range values were 1000 and 0 respectively, then each

individual pulse would be equal to 1000 divided by 10000 or 0.1. So if a

pulse train sent to the controller contained 1581 pulses, then the RSP

would be set to 158.1.

While the controller is receiving a pulse train, the RSP will remain

steady at the last received value until the pulse train has ended. At that

point, the RSP is calculated and set as shown above. A pulse train is

defined to have ended after a minimum of 2/3 seconds have elapsed with

no pulses received. At this point, the RSP is calculated and used in

control equations, so that any new pulses received are interpreted as

being the start of a new pulse train.

• REMOTE SETPOINT ADJUST PULSE UP/DOWN - The controller

adjusts the current RSP value up or down by counting the number of

pulses received and scaling the total as shown in the pulse train

example. Digital Input #1 must be used to select the desired direction of

change. Each pulse adjusts the RSP value up or down — depending on

the Digital input status (closed = pulse down, or open = pulse up) — in

increments calculated as in the pulse train example. The RSP is

calculated and set every 1/3 second while pulses are being received.

Wiring

Make sure the controller is wired to an external pulse device as shown in

the wiring diagrams in Section 2 - Installation.

Continued on next page

1 2 ... 217 218 219 220 221 222 223 224 225 226 227 ... 301 302

Komentáře k této Příručce

Žádné komentáře

United Security Products AVD-45c Manuál Strana 222

Komentáře k této Příručce

Související produkty a manuály pro Systémy intercom pro domy United Security Products AVD-45c